This study measured soil penetration resistance (PR) and soil moisture in 10 citrus orchards in Vietnam with different ages over one year. The results showed that PR increased with the age of the raised beds and varied seasonally with changes in soil moisture. PR was more strongly correlated with volumetric water content than water potential (pF values). Bulk density of the subsoil layers increased significantly with the age of the raised beds, indicating greater compaction over time. The PR and soil moisture data provided insights into soil structure and compaction that could help minimize degradation in the orchards.
Effect of vegetation cover on sediment yield an empirical study through plots...Alexander Decker
This study examined the effect of vegetation cover on sediment yield through plot experiments in a lateritic environment in India. Five experimental plots with varying vegetation cover were monitored under natural rainfall conditions. Runoff and sediment yield were measured and compared between plots. Results showed that bare plots had higher sediment yields than vegetated plots. Statistical analysis revealed significant relationships between sediment detachment and explanatory variables like runoff volume and vegetation cover. Specifically, there was a very significant relationship between vegetation cover and sediment concentration. The plot-scale experiments provided detailed monitoring of the processes and demonstrated that increased vegetation cover reduces runoff and sediment yield in this lateritic environment.
Influence of Different Soil Management Practices On Soil Properties and Its I...IOSR Journals
This document summarizes a study on the influence of different land management practices (forest land, golf course, continuous cropping) on soil properties in southeastern Nigeria. Soil samples were collected from the different land use systems and analyzed. Results showed higher levels of exchangeable bases, organic matter, total nitrogen, and available phosphorus in the top 0-20cm soil layer compared to deeper layers, and forest land generally had higher values than the other land uses. Bulk density decreased and total porosity increased with continuous cropping compared to forest land and golf course. Overall, continuous cultivation was found to deplete soil nutrients and reduce soil productivity more than the other land management practices studied.
Classification and Assessment of Soil Compaction Level in Amassoma, Bayelsa S...Premier Publishers
Soil compaction is essential in construction. The failure to displace air from between particles when constructing buildings, roads, parking lots, dams, walls, swimming pools, or utility trench inevitably leads to unwanted soil movement and water penetration into the earth beneath construction projects.Soil compaction is one of the most important aspects of any earthwork construction. Assessing the level of compaction of soil in Amassoma is to ascertain the compatibility or rate of compaction of the underlining earth materials (soils).Nine (9) samples were collected at regular intervals of 1m, 2m, 3m, 4m, 5m, 6m, 7m, 8m and 9m which were used for the analyses. The samples collected were subjected to different laboratory test to determine the index properties and the level of compaction of the soil. Sieve analysis result of the samples shows that the percentage of fines and sands are in the range of 21.57%-63.20% and 36.80% and78.73%, respectively.Atterberg result also shows that the soil liquid limit (LL) is in the range of 48.51%-54.90% plastic limit (PL) ranges from 29/13%-36.51% and 14.78%-25.18% for plastic index (PI). Another experiment shows that the value of maximum Dry Density (MD) and Optimum Moisture Content (OMC) are 1.70g/cm3 and 18 40%. The analysis done for this work reveals that the soil in the area (Amassoma) can be classified as medium to high plastic soil (unified soil classification system) and that the soil in moderately compacted. Comparing the CBR test results with the Nigeria standard, the soils found in Amassoma can be used as sub-grade materials for construction.
Determination of Some Mechanical And Hydraulic Properties Of Biu Clayey Soils...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
This document analyzes 179 field studies from 37 countries that examined the relationship between soil erosion and agricultural productivity. It finds that soil erosion negatively impacts crop yields, but the severity of impact varies significantly depending on factors like crop type, location, soil type, and land management practices. Studies using measurements of past erosion generally found smaller yield losses per unit of soil loss than studies examining the effects of present erosion, possibly because present erosion studies also captured the effects of variable management practices. The analysis calculates absolute and relative yield losses for major crops in different regions and soil types to assess the global impact of erosion on productivity. It concludes that inappropriate land management can greatly amplify the effects of erosion on yields.
Vegetation diversity on coal mine spoil heapshow important is the texture of ...EdytaSierka
Biologia, 2019
The relationship between the size of the particle fractions of the soil substrate and the diversity of the spontaneously developing vegetation was investigated on coal mine spoil heaps in Upper Silesia (Southern Poland). The analyses were based on 2567 research plots of developed spontaneous vegetation and their associated soil substrate samples collected from 112 coal mine spoil heaps. For each research plot the prevailing particle size fraction was determined (stones, gravel, sand, silt), the species composition and abundance was recorded and the species richness (S), Shannon-Wiener diversity index (H′), Simpson (C) and Evenness (E) indices were used to determine species diversity. From a total of 119 research plots (in all particle size fraction categories), the values of 15 physicochemical properties (pH, electrical conductivity, water holding capacity, moisture, carbon content, total N, available P, Mg and exchange cations Ca, Mg, K, Na, fine particles (%), gravel (%), stone (%)) were obtained to asses their impact on the floristic composition of vegetation patches using Canonical Correspondence Analysis (CCA). Additionally, functional traits of the dominant species of each vegetation patch (life forms, life strategies and socio-ecological groups), were selected to analyse their relation to substrate texture. It was shown that the highest species richness and the highest values for Shannon-Wiener diversity index, as well as Simpson and Evenness indices, were obtained in plots formed on stones. Moreover, the greatest variation in the participation of species representing different habitats, life forms, and life strategies was found on gravelly substrates. Contrary to our expectations, the vegetation diversity (in terms of both species and their functional traits) was not highest in habitats with a high composition of fine size particles.
This document summarizes a study that evaluated the effect of non-uniform longitudinal slopes due to inappropriate tillage on water advance and recession in furrow irrigation. 12 furrows of varying slopes were tested over 5 irrigation events. Results showed advance times varied significantly between furrows, from 19-50 minutes for the first irrigation. Recession times also varied widely between furrows, from 9-29 minutes. The results indicate that non-uniform slopes due to inappropriate tillage have a significant impact on advance and recession times in furrow irrigation, affecting irrigation uniformity and efficiency. More accurate land preparation and uniform furrows are needed to improve water distribution and use.
A study was conducted at a sawah site in Ghana to examine the relationship between landscape
position and some selected soil properties with the aim of generating adequate data for modeling
landscape relationships and to aid both researchers and farmers in taking critical management
decisions. Soil properties namely total porosity, moisture content, infiltration rates, hydraulic
conductivity, sand content, silt content, clay content, gravel concentration, bulk density, soil pH, total
nitrogen, soil organic matter and cation exchange capacity were collected and analysed. Data were
collected at the foot slopes, middle slopes and at the upper slopes from four major landuses (maize, oil
palm, natural vegetation and plantain) in the study area. Simple statistical parameters such as mean
and standard deviation were used to analyse the data. Moisture content, total porosity, soil pH, organic
matter and carbon and total nitrogen increased downslope whilst sand content, clay content, bulk
density occurred at upper slopes decreased downslope. Management practices appeared to have
influenced infiltration rate, hydraulic conductivity and silt content.
Effect of vegetation cover on sediment yield an empirical study through plots...Alexander Decker
This study examined the effect of vegetation cover on sediment yield through plot experiments in a lateritic environment in India. Five experimental plots with varying vegetation cover were monitored under natural rainfall conditions. Runoff and sediment yield were measured and compared between plots. Results showed that bare plots had higher sediment yields than vegetated plots. Statistical analysis revealed significant relationships between sediment detachment and explanatory variables like runoff volume and vegetation cover. Specifically, there was a very significant relationship between vegetation cover and sediment concentration. The plot-scale experiments provided detailed monitoring of the processes and demonstrated that increased vegetation cover reduces runoff and sediment yield in this lateritic environment.
Influence of Different Soil Management Practices On Soil Properties and Its I...IOSR Journals
This document summarizes a study on the influence of different land management practices (forest land, golf course, continuous cropping) on soil properties in southeastern Nigeria. Soil samples were collected from the different land use systems and analyzed. Results showed higher levels of exchangeable bases, organic matter, total nitrogen, and available phosphorus in the top 0-20cm soil layer compared to deeper layers, and forest land generally had higher values than the other land uses. Bulk density decreased and total porosity increased with continuous cropping compared to forest land and golf course. Overall, continuous cultivation was found to deplete soil nutrients and reduce soil productivity more than the other land management practices studied.
Classification and Assessment of Soil Compaction Level in Amassoma, Bayelsa S...Premier Publishers
Soil compaction is essential in construction. The failure to displace air from between particles when constructing buildings, roads, parking lots, dams, walls, swimming pools, or utility trench inevitably leads to unwanted soil movement and water penetration into the earth beneath construction projects.Soil compaction is one of the most important aspects of any earthwork construction. Assessing the level of compaction of soil in Amassoma is to ascertain the compatibility or rate of compaction of the underlining earth materials (soils).Nine (9) samples were collected at regular intervals of 1m, 2m, 3m, 4m, 5m, 6m, 7m, 8m and 9m which were used for the analyses. The samples collected were subjected to different laboratory test to determine the index properties and the level of compaction of the soil. Sieve analysis result of the samples shows that the percentage of fines and sands are in the range of 21.57%-63.20% and 36.80% and78.73%, respectively.Atterberg result also shows that the soil liquid limit (LL) is in the range of 48.51%-54.90% plastic limit (PL) ranges from 29/13%-36.51% and 14.78%-25.18% for plastic index (PI). Another experiment shows that the value of maximum Dry Density (MD) and Optimum Moisture Content (OMC) are 1.70g/cm3 and 18 40%. The analysis done for this work reveals that the soil in the area (Amassoma) can be classified as medium to high plastic soil (unified soil classification system) and that the soil in moderately compacted. Comparing the CBR test results with the Nigeria standard, the soils found in Amassoma can be used as sub-grade materials for construction.
Determination of Some Mechanical And Hydraulic Properties Of Biu Clayey Soils...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
This document analyzes 179 field studies from 37 countries that examined the relationship between soil erosion and agricultural productivity. It finds that soil erosion negatively impacts crop yields, but the severity of impact varies significantly depending on factors like crop type, location, soil type, and land management practices. Studies using measurements of past erosion generally found smaller yield losses per unit of soil loss than studies examining the effects of present erosion, possibly because present erosion studies also captured the effects of variable management practices. The analysis calculates absolute and relative yield losses for major crops in different regions and soil types to assess the global impact of erosion on productivity. It concludes that inappropriate land management can greatly amplify the effects of erosion on yields.
Vegetation diversity on coal mine spoil heapshow important is the texture of ...EdytaSierka
Biologia, 2019
The relationship between the size of the particle fractions of the soil substrate and the diversity of the spontaneously developing vegetation was investigated on coal mine spoil heaps in Upper Silesia (Southern Poland). The analyses were based on 2567 research plots of developed spontaneous vegetation and their associated soil substrate samples collected from 112 coal mine spoil heaps. For each research plot the prevailing particle size fraction was determined (stones, gravel, sand, silt), the species composition and abundance was recorded and the species richness (S), Shannon-Wiener diversity index (H′), Simpson (C) and Evenness (E) indices were used to determine species diversity. From a total of 119 research plots (in all particle size fraction categories), the values of 15 physicochemical properties (pH, electrical conductivity, water holding capacity, moisture, carbon content, total N, available P, Mg and exchange cations Ca, Mg, K, Na, fine particles (%), gravel (%), stone (%)) were obtained to asses their impact on the floristic composition of vegetation patches using Canonical Correspondence Analysis (CCA). Additionally, functional traits of the dominant species of each vegetation patch (life forms, life strategies and socio-ecological groups), were selected to analyse their relation to substrate texture. It was shown that the highest species richness and the highest values for Shannon-Wiener diversity index, as well as Simpson and Evenness indices, were obtained in plots formed on stones. Moreover, the greatest variation in the participation of species representing different habitats, life forms, and life strategies was found on gravelly substrates. Contrary to our expectations, the vegetation diversity (in terms of both species and their functional traits) was not highest in habitats with a high composition of fine size particles.
This document summarizes a study that evaluated the effect of non-uniform longitudinal slopes due to inappropriate tillage on water advance and recession in furrow irrigation. 12 furrows of varying slopes were tested over 5 irrigation events. Results showed advance times varied significantly between furrows, from 19-50 minutes for the first irrigation. Recession times also varied widely between furrows, from 9-29 minutes. The results indicate that non-uniform slopes due to inappropriate tillage have a significant impact on advance and recession times in furrow irrigation, affecting irrigation uniformity and efficiency. More accurate land preparation and uniform furrows are needed to improve water distribution and use.
A study was conducted at a sawah site in Ghana to examine the relationship between landscape
position and some selected soil properties with the aim of generating adequate data for modeling
landscape relationships and to aid both researchers and farmers in taking critical management
decisions. Soil properties namely total porosity, moisture content, infiltration rates, hydraulic
conductivity, sand content, silt content, clay content, gravel concentration, bulk density, soil pH, total
nitrogen, soil organic matter and cation exchange capacity were collected and analysed. Data were
collected at the foot slopes, middle slopes and at the upper slopes from four major landuses (maize, oil
palm, natural vegetation and plantain) in the study area. Simple statistical parameters such as mean
and standard deviation were used to analyse the data. Moisture content, total porosity, soil pH, organic
matter and carbon and total nitrogen increased downslope whilst sand content, clay content, bulk
density occurred at upper slopes decreased downslope. Management practices appeared to have
influenced infiltration rate, hydraulic conductivity and silt content.
Week 4: Important soil physical properties Suyog Khose
1. This document summarizes important physical properties of soil for engineers and agricultural professionals, including soil texture, particle size, and methods for determining soil texture through laboratory analysis.
2. The key method described is the hydrometer method, which uses the principle that particles of different sizes settle from suspension at different rates based on their surface area and size. A hydrometer is used to measure the density of soil suspensions over time to determine the percentage of sand, silt, and clay in a soil sample.
3. Determining soil texture through the hydrometer method involves dispersing soil particles, taking hydrometer readings at specific time intervals as particles settle, correcting for temperature differences, and using the percentages of sand, s
Assessment of infiltration rate under different drylands types in unter iwes ...Alexander Decker
1. The study assessed infiltration rates under different dryland types in Unter-Iwes Subdistrict, Sumbawa Besar, Indonesia using a double ring infiltrometer.
2. Measurements found the highest infiltration rates and volumes on rainfed land (45.10 cm/h and 41.82 cm3 respectively), representing very fast infiltration. The lowest rates were on 'Tegalan' land (17.70 cm/h and 17.58 cm3), representing fast infiltration.
3. Factors influencing infiltration included soil type, organic matter, porosity, bulk density, specific gravity, and initial moisture content. Estimates using the Horton model showed good agreement with field measurements.
This document summarizes restrictions on sharing and distributing an article from a journal published by Elsevier. The copy is for the author's personal non-commercial use, including instruction and sharing with colleagues. Other uses like reproduction, distribution, selling, licensing copies or posting on websites are prohibited without permission. Authors can generally post the article in Word or Tex format on their personal or institutional websites or repositories. The document provides a link for authors to check Elsevier's full archiving and manuscript policies.
Impact of Land Use Systems and Parent Materials on Soil Quality Indicators in...BRNSS Publication Hub
A study on the impact of parent materials and land use on soil quality indicators in soils of Akwa Ibom State was conducted. The aim was to evaluate the impact of parent materials and land use systems on soil quality indicators. Three parent materials (coastal plain sand, sandstone/shale, and beach ridge sand) and three land use types (cultivated land, fallow land of 3–5 years, and oil palm plantation) were selected for the study. In each land use type per parent material, six composite soil samples were collected from the representative location within the three land use types using soil auger within 0–30 cm soil depth. Undisturbed core samples were also collected for bulk density and saturated hydraulic conductivity determinations. A total of 52 soil samples were generated for laboratory analysis. Results showed that among the parent materials, coastal plain sand soil had the highest silt + clay fraction, organic matter, total N, available P, and exchangeable K, followed by sandstone/shale while beach ridge sand soil had the least. Among the land use types, oil palm plantation had the highest silt + clay fraction, organic matter, exchangeable Ca and K, followed by fallow land while cultivated land had the least. The combination of parent material and land use indicated that cultivated, fallow and oil palm plantation of coastal plain sand soils had the highest water and nutrient holding capacity, high rooting volume, good aeration status, less erosion threat, higher exchange sites, more available nutrients for plant uptake, more biological activity, etc., followed by sandstone/shale while beach ridge sand had the least in the study area. The application of more organic and less inorganic fertilizers will improve the soil quality of the study area.
This document summarizes the application of a structure-index technique to evaluate soil structure degradation in clay soils in the Nile Delta region of Egypt. The technique involves treating soil aggregates with alcohol, water, and benzene to assess stability. Structure index values from 2-12 were observed across 14 soil profiles, with higher values indicating poorer structure. Structure degradation was found in bottom layers of half the profiles. Linear relationships were observed between structure index and electrical conductivity/sodium percentage, indicating early structure degradation with increasing salinity. The newly proposed index provides a simple way to rapidly assess soil structure changes across profiles and its relation to other soil properties.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability
Feasibility of Using Tincal Ore Waste as Barrier Material for Solid Waste Con...IOSR Journals
This document investigates using tincal ore waste (TOW) as a material to improve the properties of lateritic soil barriers for containing municipal solid waste. Tests were conducted on lateritic soil alone and mixtures replacing 5-20% of the soil with TOW. All mixtures met the required unconfined compressive strength for stability. Hydraulic conductivity was lowest for mixtures with 20% TOW compacted at high energy, ranging from 2.1x10-10 to 3.2x10-12 m/s when permeated with leachate. For economic purposes, lateritic soil could meet conductivity standards compacted at 15% moisture using standard light compaction. TOW contains silica and other compounds making
1) The study investigated the impact of altitude on soil macroinvertebrate diversity in three sites along an altitudinal gradient in Xitou Experimental Forest, Taiwan.
2) The results showed an increase in macroinvertebrate species abundance from the lowest site at 1150m to the mid-elevation site at 1450m, but a decrease at the highest site of 1800m, likely due to differences in soil composition, temperature, and human disturbance across the sites.
3) Limitations of the study included an inability to identify species taxonomically, limited equipment for chemical soil analysis, small study area, and constraints of a one-day observation period.
This study examined the effects of applying diatomite, a sedimentary rock composed of fossilized diatom remains, on the physical properties of three soils with different textures (sandy loam, loam, and clay). Diatomite was applied at rates of 10%, 20%, and 30% by volume. The results showed that diatomite reduced bulk density and increased aggregate stability, field capacity, and permeability in all soils. However, it decreased mean aggregate size and protected against large aggregate formation in clay-textured soils. Overall, diatomite appears to improve some physical properties of soils and has potential as a soil amendment, though its effectiveness depends on soil texture and properties.
Research Inventy : International Journal of Engineering and Scienceresearchinventy
This document summarizes research on the liquefaction of fine-grained soils. It establishes that fine-grained soils like silts and clays can liquefy under certain conditions. The liquefaction potential of silts changes with plasticity index. There are still anomalies in understanding the effect of fines on liquefaction that require further research, such as the impact of neglecting fines below 5% and the effect of void ratio on soils with low plasticity fines. More experimental studies are needed to clarify these issues.
Variability of some physicochemical properties on Lithosequence in Funtua, Northwestern, Nigeria were studied to determine the extent of variation in physical and chemical properties within and between soils developed on basement complexes, loess over basement complexes and loess parent materials. Variability was more pronounced in chemical than in physical properties. Particle density (CV = 0.23%) and exchangeable sodium percentage (CV = 2.23) were the least variable physicochemical properties. Physicochemical properties with highest variability are Si/C ratio (CV =88.29%) and AP (CV = 149%). Less variability (CV ≤ 15%) irrespective of soils were recorded in particle density, bulk density and pH, and therefore required similar management for all the soils. Silt, AWHC, CEC, CEC clay and base saturation were consistently moderately variable (CV: >15 ≤ 35%). Silt/clay ratio, K, OC, TN, AP and AS were consistently highly variable CV > 35%). Large proportion of properties of the soils were highly variable in all the soils with 10 (42%) of physicochemical properties of soils on BC, 9 (38%) on LBC and 13 (54%) on LS. The highly variable status was attributed to difference in land use types, management and cultural practices occurring within the study area. Properties significantly influenced by Lithosequence include available water holding capacity, magnesium, potassium, CEC and TEA. They were significantly highest in soils on loess and contributed to variation in pattern of nutrient and exchangeable bases retention.
This document discusses erosivity and erodibility. It defines erosivity as the ability of rainfall to cause erosion, which depends on factors like rainfall intensity, amount, and drop size. Two common methods to estimate erosivity from rainfall data are presented: the EI30 index method and KE>25 index method. Erodibility is defined as a soil's susceptibility to erosion, which depends on physical properties like texture, structure, and organic matter. The relationship between erosivity and erodibility is that erosivity depends on rainfall characteristics while erodibility depends on soil properties, and both factors must be considered to understand soil erosion.
Erodibility of slash and-burn soils along a toposequence in relation to four ...Alexander Decker
This document summarizes a study on the erodibility of soils after slash-and-burn agriculture in southeastern Nigeria. Soil samples were collected from plots along a hillslope before and after burning to analyze changes in properties. Results showed burning increased bulk density and decreased porosity by disrupting soil structure. Burning also increased pH and nutrients but decreased organic carbon. Erodibility increased by 14-20% after burning across landscape positions. Soil pH had the strongest correlation with erodibility. However, the specific amounts of ash added from burning were unknown.
IRJET- Effect of Marble Dust and Paddy Straw on the Strength Characteristics ...IRJET Journal
This document discusses a study on the effect of adding marble dust and paddy straw to clayey soil on its strength characteristics. The researchers found that adding optimal amounts of these waste materials significantly improved the strength, durability and reduced the swelling and plasticity of the clayey soil. Based on the results, the researchers recommend considering marble dust and paddy straw mixtures as a viable option for increasing the strength of clayey soils. The document provides background on soil classification, engineering properties of soils, and the need for and advantages of soil stabilization.
The document summarizes a study that investigated stabilizing clay soil with lime and melon husk ash. Key findings include:
1) The natural clay soil was classified as highly plastic (CH) and had low strength, making it unsuitable for construction without treatment.
2) Chemical analysis found the melon husk ash met requirements to be a pozzolanic material, with high concentrations of aluminum, iron, and silicon oxides.
3) Testing showed that adding both lime and melon husk ash to the clay soil increased its unconfined compressive strength and decreased its permeability compared to the untreated soil. The highest strength was achieved with 6% melon husk ash and 8% lime
IRJET- Stabilization of Black Cotton Soil by using Waste GypsumIRJET Journal
The document summarizes a study on stabilizing black cotton soil using waste gypsum. Black cotton soil is problematic due to high swelling and shrinkage. The study aims to improve the engineering properties of black cotton soil like bearing capacity and permeability by adding waste gypsum as a stabilizer. A series of tests were conducted on the black cotton soil to determine its basic properties. These included specific gravity, plastic limit, liquid limit, free swell index, and standard Proctor tests. The soil was then mixed with different percentages of waste gypsum and re-tested, including California Bearing Ratio tests, to analyze the improvement in strength parameters. The results showed increased unconfined compressive strength and California Bearing Ratio values, indicating waste
Variability in the physicochemical properties of soils of different land uses form from the same lithology was studied. Soil samples were collected from surface (0 – 20 cm) and subsurface (20 – 40 cm) depths from three land use namely fallow land, continuous cultivated land and mechanic village land. The soils were air dried, sieved with 2 mm sieve and subjected to routine laboratory analysis. Results obtained were subjected to analysis of variance (ANOVA) and significant treatment means were separated using Least Significant Difference (LSD) at 0.05 probability level. Relationship between selected soil properties were determined using correlation analysis. Results showed that the textures of the studied soils were not affected by land use practices. Bulk density increased with increase in depth with fallow land recoding the lowest values of 0.86 g/cm3 (0.-20 cm depth) and 1.06 g/cm3 (20 – 40 cm depth). Land use types significantly (P = 0.05) affected soil chemical properties such as soil pH, soil organic carbon, total N, available P and exchangeable cations with the highest values recorded in fallow land, followed by palm plantation and the least was continuous cultivated land. There were slight variations among soil properties in the three land use types studied. Significant positive and negative correlations existed and some soil properties. Good soil management practices such as organic fertilization, zero tillage and mulching is recommended especially in continuous cultivated lands.
Week 4: Important soil physical properties Suyog Khose
1. This document summarizes important physical properties of soil for engineers and agricultural professionals, including soil texture, particle size, and methods for determining soil texture through laboratory analysis.
2. The key method described is the hydrometer method, which uses the principle that particles of different sizes settle from suspension at different rates based on their surface area and size. A hydrometer is used to measure the density of soil suspensions over time to determine the percentage of sand, silt, and clay in a soil sample.
3. Determining soil texture through the hydrometer method involves dispersing soil particles, taking hydrometer readings at specific time intervals as particles settle, correcting for temperature differences, and using the percentages of sand, s
Assessment of infiltration rate under different drylands types in unter iwes ...Alexander Decker
1. The study assessed infiltration rates under different dryland types in Unter-Iwes Subdistrict, Sumbawa Besar, Indonesia using a double ring infiltrometer.
2. Measurements found the highest infiltration rates and volumes on rainfed land (45.10 cm/h and 41.82 cm3 respectively), representing very fast infiltration. The lowest rates were on 'Tegalan' land (17.70 cm/h and 17.58 cm3), representing fast infiltration.
3. Factors influencing infiltration included soil type, organic matter, porosity, bulk density, specific gravity, and initial moisture content. Estimates using the Horton model showed good agreement with field measurements.
This document summarizes restrictions on sharing and distributing an article from a journal published by Elsevier. The copy is for the author's personal non-commercial use, including instruction and sharing with colleagues. Other uses like reproduction, distribution, selling, licensing copies or posting on websites are prohibited without permission. Authors can generally post the article in Word or Tex format on their personal or institutional websites or repositories. The document provides a link for authors to check Elsevier's full archiving and manuscript policies.
Impact of Land Use Systems and Parent Materials on Soil Quality Indicators in...BRNSS Publication Hub
A study on the impact of parent materials and land use on soil quality indicators in soils of Akwa Ibom State was conducted. The aim was to evaluate the impact of parent materials and land use systems on soil quality indicators. Three parent materials (coastal plain sand, sandstone/shale, and beach ridge sand) and three land use types (cultivated land, fallow land of 3–5 years, and oil palm plantation) were selected for the study. In each land use type per parent material, six composite soil samples were collected from the representative location within the three land use types using soil auger within 0–30 cm soil depth. Undisturbed core samples were also collected for bulk density and saturated hydraulic conductivity determinations. A total of 52 soil samples were generated for laboratory analysis. Results showed that among the parent materials, coastal plain sand soil had the highest silt + clay fraction, organic matter, total N, available P, and exchangeable K, followed by sandstone/shale while beach ridge sand soil had the least. Among the land use types, oil palm plantation had the highest silt + clay fraction, organic matter, exchangeable Ca and K, followed by fallow land while cultivated land had the least. The combination of parent material and land use indicated that cultivated, fallow and oil palm plantation of coastal plain sand soils had the highest water and nutrient holding capacity, high rooting volume, good aeration status, less erosion threat, higher exchange sites, more available nutrients for plant uptake, more biological activity, etc., followed by sandstone/shale while beach ridge sand had the least in the study area. The application of more organic and less inorganic fertilizers will improve the soil quality of the study area.
This document summarizes the application of a structure-index technique to evaluate soil structure degradation in clay soils in the Nile Delta region of Egypt. The technique involves treating soil aggregates with alcohol, water, and benzene to assess stability. Structure index values from 2-12 were observed across 14 soil profiles, with higher values indicating poorer structure. Structure degradation was found in bottom layers of half the profiles. Linear relationships were observed between structure index and electrical conductivity/sodium percentage, indicating early structure degradation with increasing salinity. The newly proposed index provides a simple way to rapidly assess soil structure changes across profiles and its relation to other soil properties.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability
Feasibility of Using Tincal Ore Waste as Barrier Material for Solid Waste Con...IOSR Journals
This document investigates using tincal ore waste (TOW) as a material to improve the properties of lateritic soil barriers for containing municipal solid waste. Tests were conducted on lateritic soil alone and mixtures replacing 5-20% of the soil with TOW. All mixtures met the required unconfined compressive strength for stability. Hydraulic conductivity was lowest for mixtures with 20% TOW compacted at high energy, ranging from 2.1x10-10 to 3.2x10-12 m/s when permeated with leachate. For economic purposes, lateritic soil could meet conductivity standards compacted at 15% moisture using standard light compaction. TOW contains silica and other compounds making
1) The study investigated the impact of altitude on soil macroinvertebrate diversity in three sites along an altitudinal gradient in Xitou Experimental Forest, Taiwan.
2) The results showed an increase in macroinvertebrate species abundance from the lowest site at 1150m to the mid-elevation site at 1450m, but a decrease at the highest site of 1800m, likely due to differences in soil composition, temperature, and human disturbance across the sites.
3) Limitations of the study included an inability to identify species taxonomically, limited equipment for chemical soil analysis, small study area, and constraints of a one-day observation period.
This study examined the effects of applying diatomite, a sedimentary rock composed of fossilized diatom remains, on the physical properties of three soils with different textures (sandy loam, loam, and clay). Diatomite was applied at rates of 10%, 20%, and 30% by volume. The results showed that diatomite reduced bulk density and increased aggregate stability, field capacity, and permeability in all soils. However, it decreased mean aggregate size and protected against large aggregate formation in clay-textured soils. Overall, diatomite appears to improve some physical properties of soils and has potential as a soil amendment, though its effectiveness depends on soil texture and properties.
Research Inventy : International Journal of Engineering and Scienceresearchinventy
This document summarizes research on the liquefaction of fine-grained soils. It establishes that fine-grained soils like silts and clays can liquefy under certain conditions. The liquefaction potential of silts changes with plasticity index. There are still anomalies in understanding the effect of fines on liquefaction that require further research, such as the impact of neglecting fines below 5% and the effect of void ratio on soils with low plasticity fines. More experimental studies are needed to clarify these issues.
Variability of some physicochemical properties on Lithosequence in Funtua, Northwestern, Nigeria were studied to determine the extent of variation in physical and chemical properties within and between soils developed on basement complexes, loess over basement complexes and loess parent materials. Variability was more pronounced in chemical than in physical properties. Particle density (CV = 0.23%) and exchangeable sodium percentage (CV = 2.23) were the least variable physicochemical properties. Physicochemical properties with highest variability are Si/C ratio (CV =88.29%) and AP (CV = 149%). Less variability (CV ≤ 15%) irrespective of soils were recorded in particle density, bulk density and pH, and therefore required similar management for all the soils. Silt, AWHC, CEC, CEC clay and base saturation were consistently moderately variable (CV: >15 ≤ 35%). Silt/clay ratio, K, OC, TN, AP and AS were consistently highly variable CV > 35%). Large proportion of properties of the soils were highly variable in all the soils with 10 (42%) of physicochemical properties of soils on BC, 9 (38%) on LBC and 13 (54%) on LS. The highly variable status was attributed to difference in land use types, management and cultural practices occurring within the study area. Properties significantly influenced by Lithosequence include available water holding capacity, magnesium, potassium, CEC and TEA. They were significantly highest in soils on loess and contributed to variation in pattern of nutrient and exchangeable bases retention.
This document discusses erosivity and erodibility. It defines erosivity as the ability of rainfall to cause erosion, which depends on factors like rainfall intensity, amount, and drop size. Two common methods to estimate erosivity from rainfall data are presented: the EI30 index method and KE>25 index method. Erodibility is defined as a soil's susceptibility to erosion, which depends on physical properties like texture, structure, and organic matter. The relationship between erosivity and erodibility is that erosivity depends on rainfall characteristics while erodibility depends on soil properties, and both factors must be considered to understand soil erosion.
Erodibility of slash and-burn soils along a toposequence in relation to four ...Alexander Decker
This document summarizes a study on the erodibility of soils after slash-and-burn agriculture in southeastern Nigeria. Soil samples were collected from plots along a hillslope before and after burning to analyze changes in properties. Results showed burning increased bulk density and decreased porosity by disrupting soil structure. Burning also increased pH and nutrients but decreased organic carbon. Erodibility increased by 14-20% after burning across landscape positions. Soil pH had the strongest correlation with erodibility. However, the specific amounts of ash added from burning were unknown.
IRJET- Effect of Marble Dust and Paddy Straw on the Strength Characteristics ...IRJET Journal
This document discusses a study on the effect of adding marble dust and paddy straw to clayey soil on its strength characteristics. The researchers found that adding optimal amounts of these waste materials significantly improved the strength, durability and reduced the swelling and plasticity of the clayey soil. Based on the results, the researchers recommend considering marble dust and paddy straw mixtures as a viable option for increasing the strength of clayey soils. The document provides background on soil classification, engineering properties of soils, and the need for and advantages of soil stabilization.
The document summarizes a study that investigated stabilizing clay soil with lime and melon husk ash. Key findings include:
1) The natural clay soil was classified as highly plastic (CH) and had low strength, making it unsuitable for construction without treatment.
2) Chemical analysis found the melon husk ash met requirements to be a pozzolanic material, with high concentrations of aluminum, iron, and silicon oxides.
3) Testing showed that adding both lime and melon husk ash to the clay soil increased its unconfined compressive strength and decreased its permeability compared to the untreated soil. The highest strength was achieved with 6% melon husk ash and 8% lime
IRJET- Stabilization of Black Cotton Soil by using Waste GypsumIRJET Journal
The document summarizes a study on stabilizing black cotton soil using waste gypsum. Black cotton soil is problematic due to high swelling and shrinkage. The study aims to improve the engineering properties of black cotton soil like bearing capacity and permeability by adding waste gypsum as a stabilizer. A series of tests were conducted on the black cotton soil to determine its basic properties. These included specific gravity, plastic limit, liquid limit, free swell index, and standard Proctor tests. The soil was then mixed with different percentages of waste gypsum and re-tested, including California Bearing Ratio tests, to analyze the improvement in strength parameters. The results showed increased unconfined compressive strength and California Bearing Ratio values, indicating waste
Variability in the physicochemical properties of soils of different land uses form from the same lithology was studied. Soil samples were collected from surface (0 – 20 cm) and subsurface (20 – 40 cm) depths from three land use namely fallow land, continuous cultivated land and mechanic village land. The soils were air dried, sieved with 2 mm sieve and subjected to routine laboratory analysis. Results obtained were subjected to analysis of variance (ANOVA) and significant treatment means were separated using Least Significant Difference (LSD) at 0.05 probability level. Relationship between selected soil properties were determined using correlation analysis. Results showed that the textures of the studied soils were not affected by land use practices. Bulk density increased with increase in depth with fallow land recoding the lowest values of 0.86 g/cm3 (0.-20 cm depth) and 1.06 g/cm3 (20 – 40 cm depth). Land use types significantly (P = 0.05) affected soil chemical properties such as soil pH, soil organic carbon, total N, available P and exchangeable cations with the highest values recorded in fallow land, followed by palm plantation and the least was continuous cultivated land. There were slight variations among soil properties in the three land use types studied. Significant positive and negative correlations existed and some soil properties. Good soil management practices such as organic fertilization, zero tillage and mulching is recommended especially in continuous cultivated lands.
Progetto ELI4U - Convegno Conclusivo - WP2 - Attività 3 - Comune di CesenaProgettoELI4U
Presentazione, nell'ambito del Convegno Conclusivo del Progetto ELI4U intitolato "Innovare nella PA in tempi di crisi" tenutosi a Cesena il 6 Dicembre 2012, delle attività effettuate e dei prodotti realizzati nell'ambito del Work Package 2 - Attività 3, da parte del Comune di Cesena.
The document discusses the vision of being a highly effective and results-oriented global energy company that is admired for its people, partnerships, and performance. The vision includes safely providing vital energy products, having superior capabilities and commitment, being the partner of choice, and earning admiration through world-class performance and how goals are achieved.
The document summarizes quotes from speakers at the 2012 CEA Forum about business, opportunities, and digital health. Leaders in the consumer electronics industry gathered to learn and connect. Speakers provided insight on having the margin come from customer relationships rather than products; on skills becoming a new currency as influence replaces affluence; and on the need to create disruptive technology before competitors to stay ahead of changes that seem slow but then happen rapidly. Other quotes addressed investing in innovations that will improve lives in 10 years; building companies focused on social good; and the potential of digital health for prevention through tools that measure, monitor, and motivate behavior changes.
This document provides tips for earning a profit using Craigslist. It discusses how independent contractors and small business owners can use Craigslist to find work or advertise their services. Specific tips include creating an account for easier posting, including pictures in listings to attract more interest, and searching by location and keywords when looking for jobs or services. The document promotes Craigslist as an affordable advertising platform with a large audience.
1.THE INFLUENCE OF THE PERLITE AS A SUBSTRATE FOR IMPROVING ON SOME WATER.pdfMaqsoodKhalid3
THE INFLUENCE OF THE PERLITE AS A SUBSTRATE FOR IMPROVING ON SOME WATER.
The adsorption on molecular sieves is therefore dependent on the following physical molecular properties:
- Size and Shape; molecules or ions larger than the pore opening of the zeolite can not be adsorbed, smaller molecules or ions can.
-Molecular Polarity; due the charge on outer and inner zeolitic surface particle, molecules with large polarity or polarisability can be adsorbed preferentially under identical conditions
This document discusses the high sensitivity of Chinese red clay soils to drought. It analyzes the water retention properties of red clay soils from Hunan province, China and compares them to clay soils from other parts of the world. The results show that the amount of water available between water potentials of -330 and -15,000 hPa in the Chinese red clay soils is consistent with other clay soils worldwide. However, the proportion of poorly available water between -3,300 and -15,000 hPa is much higher in the Chinese red clay soils. This poor water availability is thought to be related to the history of the parent materials, which were continental sediments that may have experienced great hydric stress, leading to strongly consolidated soils
This document summarizes a study that used remote sensing techniques to monitor and map soil salinity in the Tuz Lake region of Turkey from 1990 to 2015. The study analyzed 25 Landsat satellite images from 1990, 2002, 2006, 2011 and 2015 to calculate soil salinity indices and generate salinity maps for each time period. Field measurements of soil electrical conductivity from 2002 were used to relate the satellite-derived indices to actual soil salinity. Land cover data from 2000-2006 and 2006-2012 was also analyzed to detect changes that could impact salinity levels. The results showed the salinity index that combined the blue and red bands had the best correlation to field measurements. The maps produced can help track changes in salt-affected areas
The Effects Of Different Water Stress And Perlite Media On Growing Of Pepper ...MaqsoodKhalid3
The Effects Of Different Water Stress And Perlite Media On Growing Of Pepper Plant.
A zeolite mineral is a crystalline substance with a structure characterized by a framework of linked tetrahedra, each consisting of four O atoms surrounding a cation. This framework contains open cavities in the form of channels and cages. These are usually occupied by H2O molecules and extra-framework cations that are commonly exchangeable. The channels are large enough to allow the passage of guest species. In the hydrated phases, dehydration occurs at temperatures mostly below about 400 °C and is largely reversible. The framework may be interrupted by (OH, F) groups; these occupy a tetrahedron apex that is not shared with adjacent tetrahedra.
The document compares soil moisture measurements from the ESTAR satellite sensor to outputs from the GEOtop hydrological model during the Southern Great Plains Hydrology Experiments of 1997 and 1999. The model is first calibrated using 1997 data and validated using 1999 data. Soil moisture, soil temperature, heat and water fluxes, and discharge are found to agree well between the model and ground measurements. The model is then used to evaluate ESTAR soil moisture products, finding they overestimate soil moisture during and immediately after rainfall events likely due to contamination from surface runoff and intercepted rain. Topography, vegetation, and surface runoff effects are investigated in the ESTAR-model comparison.
Hydrological and physical changes of soils under cocoa plantations of differe...Alexander Decker
This document summarizes a study that assessed hydrological and physical changes in soils under cocoa plantations of different ages during the dry season in Ghana. The study measured parameters like bulk density, porosity, organic matter, soil moisture, potential evaporation, and leaf litter accumulation in plots representing grassland (control) and cocoa plantations aged 3, 4, and 5 years. The 5-year old plantation had the highest soil moisture, porosity, organic matter, and litter fall, and lowest bulk density and evaporation. Soil moisture correlated positively with porosity and litter accumulation but negatively with bulk density and evaporation. The results suggest that soil properties influenced by the age of cocoa plantations can impact soil moisture retention under dry
This document summarizes the findings of a 16-year field experiment comparing the effects of no-tillage with straw cover (NTSC) and traditional tillage with straw removal (TTSR) on soil properties in a winter wheat cropping system on the Loess Plateau in China. The study found that NTSC increased soil organic matter by 21.7% and total nitrogen by 51% in the top 10 cm of soil, and available phosphorus by 97.3% in the top 5 cm, compared to TTSR. Microbial biomass carbon and nitrogen were also 135.3% and 104.4% higher under NTSC. Winter wheat yields were approximately 15.5% greater with NTSC. The results
Properties of Soil Agricultural and Water Availability Impa.docxwoodruffeloisa
Properties of Soil: Agricultural
and Water Availability Impacts
Investigation
Manual
ENVIRONMENTAL SCIENCE
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PROPERTIES OF SOIL: AGRICULTURAL AND WATER
AVAILABILITY IMPACTS
Overview
Earth’s soil plays a major role in the world’s agriculture and has a
substantial effect on water availability in a given area. In this inves-
tigation, students will analyze the natural porosity and particle size
of soil samples along with the chemical composition and profile of
different soil types.
Outcomes
• Examine the properties of soil and their effects on agriculture
and water availability.
• Describe and identify soil horizons based on their chemical and
physical composition.
• Distinguish between the particle sizes of three different types of
soil: sand, silt, and clay.
• Determine the porosity of different soil types.
• Analyze soil samples for a variety of nutrients to determine soil
fertility.
Time Requirements
Preparation ....................................................................... 5 minutes
Activity 1: Particle Size Distribution and Determination of Soil
Texture
Day 1 ...................... 20 minutes, then let sit for 24 hours
Day 2 ............................................................. 30 minutes
Activity 2: Porosity of Different Soil Types ...................... 60 minutes
Activity 3: pH Test Comparison of Soil Samples ............ 30 minutes
Activity 4: Nitrogen, Phosphorus, and Potash Test Comparisons of
Soil Samples
Day 1 ...................... 20 minutes, then let sit for 24 hours
Day 2 ............................................................. 60 minutes
2 Carolina Distance Learning
Table of Contents
2 Overview
2 Outcomes
2 Time Requirements
3 Background
10 Materials
11 Safety
11 Preparation
12 Activity 1
13 Activity 2
14 Activity 3
16 Submission
16 Disposal and Cleanup
17 Lab Worksheet
Background
Soil Horizons and Chemical Composition
The type of dirt that makes up the dry
surfaces of the earth has numerous effects on
humans and the environment, and vice versa.
Humans can modify the suitability of some
areas for agriculture based on prior land use.
The properties of soil also determine water
availability in a given area. Areas that contain the
most suitable soil for farming are often limited.
Certain properties of soil determine whether
an area is suitable for human activity. When
considering the properties of soil, its texture,
shape, particle aggregation, and suitability for
growth come to mind. These properties all play
a major role in determining the capability of an
area to retain water and air, which are necessary
f ...
The document describes a study that investigated the influence of swelling on the stress-strain behavior, shear strength, and elasticity modulus of expansive soils under various confining pressures. Laboratory tests were conducted using triaxial apparatus on specimens of expansive clay from Indonesia that were compacted at optimum moisture content and maximum dry density. The tests measured stress-strain behavior, shear strength, and elasticity modulus both before and after allowing specimens to swell under confining pressures of 50, 70, and 90 kPa. The results showed that shear strength and elasticity modulus decreased significantly, by 73-88%, after swelling compared to before swelling.
The document summarizes research on modeling and analyzing soil moisture patterns at the basin scale using ground-based field data and remote sensing results. Key findings include:
1) For wet conditions, soil moisture variance increases with spatial scale following a power law, while for dry conditions variance is spatially uniform and independent of scale.
2) Soil moisture variance and correlation length depend on basin wetness. Spatial correlation follows a power law decay up to 1 km and exhibits multiscaling at larger scales.
3) Modeling results using GEOtop agree with remote sensing results from ESTAR in characterizing soil moisture variability and correlation.
This document discusses a study on the effect of land use change from paddy fields to vegetable fields on residues of organochlorine pesticides (OCPs) in soils. Soil samples were taken from vegetable fields that had been converted from paddy fields for 0 to 50 years. The mean concentrations of various OCPs were measured, with DDTs being the highest. Residues of OCPs, especially DDTs, increased over the first 15 years after conversion and then decreased from 20 to 30 years before increasing slightly after 30 years. The changes in OCP residues over time are suggested to be controlled by the alternating aerobic and anaerobic conditions in the soils.
INTERNSHIP REPORT
Work completed at
Soil Physics Research Program
LAND RESOURCES RESEARCH INSTITUTE
NATIONAL AGRICULTURAL REASERCH CENTRE ISLAMABAD
Relationship of Soil Physical & Chemical Properties with Aggregate Stability in Rice-Wheat Soil
Paul Okon ICTP-SSSN workshop on Soil Physics ABU Zaria.pptxPaulBOkon
This document proposes the development of an early warning system to monitor changes in soil quality under tropical conditions. It discusses the need for a standardized model to quantify soil quality in the tropics using key physical, chemical, biological and climatic indicators. The author aims to develop a comprehensive tropical soil quality index and model that incorporates soil forming factors like parent material, organisms, climate, relief, time and land use/management. It outlines the goals, justification and methodology for selecting soil properties and land uses to evaluate. Critical limits for indicators are presented and the summation of property scores into an overall soil quality grade is described. The proposed system seeks to predict degradation risks and support more sustainable land management in tropical regions.
The document summarizes a study that assessed the vulnerability of aquifers in the Imo River Basin in southeastern Nigeria to pollution. Eight locations were investigated to determine parameters like depth to water table, recharge rate, aquifer and soil properties, topography, and hydraulic conductivity. These parameters were used in the DRASTIC model to develop a vulnerability map. The map showed that areas within the Benin Formation generally have moderate vulnerability due to fine to coarse grained sandy overburden. Higher vulnerabilities were found near Aba, while lower vulnerabilities occurred around Obibiezena and Naze. The study demonstrated the usefulness of the DRASTIC model for assessing vulnerability of aquifer systems.
Effect of different Grass Species on Soil Loss, and Runoff at Assosa, Benisha...BRNSSPublicationHubI
Land degradation is a severe environmental problem across sub-Saharan Africa, and Ethiopia is among the most affected countries. This study aimed to know the potential of different grasses for soil and water conservation. Three different grasses were used to evaluate their potential for conserving the soil and water on the farmland, with three replications each for 2 consecutive years. Vetiver, Desho, and elephant grass had deposited 10 and 7 ton/he of soil relative to a plot without any grass control. Furthermore, they had increased the soil water by 22.6% as compared to a plot without any grass. Thus, the study revealed the best potential of Vetiver, and Desho grass to conserve both the soil and water. Therefore, the study revealed the best and most promising potential for treating degraded land with biological measures.
Physicochemical analysis of a soil near microbiology laboratory at the univer...Alexander Decker
This study analyzed the physicochemical properties of soil near a microbiology laboratory at the University of Ilorin in Nigeria over six sampling periods. The pH ranged from 7.10 to 7.82, moisture content was between 2.10-5.23%, organic matter was 3.42-4.70%, and water holding capacity was 0.28-0.53 ml/g. The soil texture was determined to be loamy sand with 89% sand, 7% silt, and 4% clay on average. The results indicate the soil properties were suitable for microbial growth and plant development.
impacts of biodegradable organics on soil and gwMarwan Haddad
This study investigated the impact of biological oxygen demand (BOD) on soil and groundwater in two areas of the West Bank - Jericho and Talkarem. Soil samples were collected from each area and subjected to simulated rainfall in columns, with some columns receiving water containing BOD and others receiving only water. The concentration of BOD, total dissolved solids (TDS), and dissolved oxygen (DO) were measured in the leachate from the columns over time, simulating the effects of 1, 10, and 25 years of rainfall. The results showed that BOD concentration increased with time and depth in the soil columns, and was generally higher in Talkarem soil than Jericho soil. TDS levels also
Ground Improvement of Dune Sand Fields For The Purpose of Moisture RetentionIJERA Editor
Plant growth depends on the use of two important natural resources, soil and water. Soil provides the mechanical and nutrient support necessary for plant growth. Water is the major input for the growth and development of all types of plants. The availability of water, its movement and its retention are governed by the properties of soil. The properties like bulk density, mechanical composition, hydraulic conductivity etc depends on the nature and formation of soil and land use characteristics in addition to the weathering processes and the geological formations. Effective management of the resources for crop production requires the need to understand relationship between soil, water and plants. Study of soil and its water holding capacity is essential for the efficient utilization of irrigation water. Hence identification of geotechnical parameters which influences the water retention capacity and the method of adding admixtures to improve the retention capacity play an important role in Irrigation Engineering. This Paper aims to focuses on improving moisture retention of soil by addition of bentonite clay and experimental analysis for monitoring the variation of moisture retention.
This document discusses how integrated geophysical methods can improve agricultural practices in tropical environments. It reviews three commonly used geophysical methods: ground penetrating radar (GPR), electrical resistivity, and electromagnetic induction. GPR measures dielectric properties related to soil water content. Electrical resistivity measures electrical conductivity, which correlates with soil properties like texture, drainage, salinity, and depth to clay layers. Electromagnetic induction provides large-scale, rapid surveys of apparent electrical conductivity before more detailed GPR or resistivity surveys. Together these non-invasive geophysical methods can map soil spatial variability, monitor soil moisture, identify saline areas, and delineate subsurface features to enhance soil management and agricultural productivity.
Similar to Welcome to International Journal of Engineering Research and Development (IJERD) (20)
A Novel Method for Prevention of Bandwidth Distributed Denial of Service AttacksIJERD Editor
Distributed Denial of Service (DDoS) Attacks became a massive threat to the Internet. Traditional
Architecture of internet is vulnerable to the attacks like DDoS. Attacker primarily acquire his army of Zombies,
then that army will be instructed by the Attacker that when to start an attack and on whom the attack should be
done. In this paper, different techniques which are used to perform DDoS Attacks, Tools that were used to
perform Attacks and Countermeasures in order to detect the attackers and eliminate the Bandwidth Distributed
Denial of Service attacks (B-DDoS) are reviewed. DDoS Attacks were done by using various Flooding
techniques which are used in DDoS attack.
The main purpose of this paper is to design an architecture which can reduce the Bandwidth
Distributed Denial of service Attack and make the victim site or server available for the normal users by
eliminating the zombie machines. Our Primary focus of this paper is to dispute how normal machines are
turning into zombies (Bots), how attack is been initiated, DDoS attack procedure and how an organization can
save their server from being a DDoS victim. In order to present this we implemented a simulated environment
with Cisco switches, Routers, Firewall, some virtual machines and some Attack tools to display a real DDoS
attack. By using Time scheduling, Resource Limiting, System log, Access Control List and some Modular
policy Framework we stopped the attack and identified the Attacker (Bot) machines
Hearing loss is one of the most common human impairments. It is estimated that by year 2015 more
than 700 million people will suffer mild deafness. Most can be helped by hearing aid devices depending on the
severity of their hearing loss. This paper describes the implementation and characterization details of a dual
channel transmitter front end (TFE) for digital hearing aid (DHA) applications that use novel micro
electromechanical- systems (MEMS) audio transducers and ultra-low power-scalable analog-to-digital
converters (ADCs), which enable a very-low form factor, energy-efficient implementation for next-generation
DHA. The contribution of the design is the implementation of the dual channel MEMS microphones and powerscalable
ADC system.
Influence of tensile behaviour of slab on the structural Behaviour of shear c...IJERD Editor
-A composite beam is composed of a steel beam and a slab connected by means of shear connectors
like studs installed on the top flange of the steel beam to form a structure behaving monolithically. This study
analyzes the effects of the tensile behavior of the slab on the structural behavior of the shear connection like slip
stiffness and maximum shear force in composite beams subjected to hogging moment. The results show that the
shear studs located in the crack-concentration zones due to large hogging moments sustain significantly smaller
shear force and slip stiffness than the other zones. Moreover, the reduction of the slip stiffness in the shear
connection appears also to be closely related to the change in the tensile strain of rebar according to the increase
of the load. Further experimental and analytical studies shall be conducted considering variables such as the
reinforcement ratio and the arrangement of shear connectors to achieve efficient design of the shear connection
in composite beams subjected to hogging moment.
Gold prospecting using Remote Sensing ‘A case study of Sudan’IJERD Editor
Gold has been extracted from northeast Africa for more than 5000 years, and this may be the first
place where the metal was extracted. The Arabian-Nubian Shield (ANS) is an exposure of Precambrian
crystalline rocks on the flanks of the Red Sea. The crystalline rocks are mostly Neoproterozoic in age. ANS
includes the nations of Israel, Jordan. Egypt, Saudi Arabia, Sudan, Eritrea, Ethiopia, Yemen, and Somalia.
Arabian Nubian Shield Consists of juvenile continental crest that formed between 900 550 Ma, when intra
oceanic arc welded together along ophiolite decorated arc. Primary Au mineralization probably developed in
association with the growth of intra oceanic arc and evolution of back arc. Multiple episodes of deformation
have obscured the primary metallogenic setting, but at least some of the deposits preserve evidence that they
originate as sea floor massive sulphide deposits.
The Red Sea Hills Region is a vast span of rugged, harsh and inhospitable sector of the Earth with
inimical moon-like terrain, nevertheless since ancient times it is famed to be an abode of gold and was a major
source of wealth for the Pharaohs of ancient Egypt. The Pharaohs old workings have been periodically
rediscovered through time. Recent endeavours by the Geological Research Authority of Sudan led to the
discovery of a score of occurrences with gold and massive sulphide mineralizations. In the nineties of the
previous century the Geological Research Authority of Sudan (GRAS) in cooperation with BRGM utilized
satellite data of Landsat TM using spectral ratio technique to map possible mineralized zones in the Red Sea
Hills of Sudan. The outcome of the study mapped a gossan type gold mineralization. Band ratio technique was
applied to Arbaat area and a signature of alteration zone was detected. The alteration zones are commonly
associated with mineralization. The alteration zones are commonly associated with mineralization. A filed check
confirmed the existence of stock work of gold bearing quartz in the alteration zone. Another type of gold
mineralization that was discovered using remote sensing is the gold associated with metachert in the Atmur
Desert.
Reducing Corrosion Rate by Welding DesignIJERD Editor
This document summarizes a study on reducing corrosion rates in steel through welding design. The researchers tested different welding groove designs (X, V, 1/2X, 1/2V) and preheating temperatures (400°C, 500°C, 600°C) on ferritic malleable iron samples. Testing found that X and V groove designs with 500°C and 600°C preheating had corrosion rates of 0.5-0.69% weight loss after 14 days, compared to 0.57-0.76% for 400°C preheating. Higher preheating reduced residual stresses which decreased corrosion. Residual stresses were 1.7 MPa for optimal X groove and 600°C
Router 1X3 – RTL Design and VerificationIJERD Editor
Routing is the process of moving a packet of data from source to destination and enables messages
to pass from one computer to another and eventually reach the target machine. A router is a networking device
that forwards data packets between computer networks. It is connected to two or more data lines from different
networks (as opposed to a network switch, which connects data lines from one single network). This paper,
mainly emphasizes upon the study of router device, it‟s top level architecture, and how various sub-modules of
router i.e. Register, FIFO, FSM and Synchronizer are synthesized, and simulated and finally connected to its top
module.
Active Power Exchange in Distributed Power-Flow Controller (DPFC) At Third Ha...IJERD Editor
This paper presents a component within the flexible ac-transmission system (FACTS) family, called
distributed power-flow controller (DPFC). The DPFC is derived from the unified power-flow controller (UPFC)
with an eliminated common dc link. The DPFC has the same control capabilities as the UPFC, which comprise
the adjustment of the line impedance, the transmission angle, and the bus voltage. The active power exchange
between the shunt and series converters, which is through the common dc link in the UPFC, is now through the
transmission lines at the third-harmonic frequency. DPFC multiple small-size single-phase converters which
reduces the cost of equipment, no voltage isolation between phases, increases redundancy and there by
reliability increases. The principle and analysis of the DPFC are presented in this paper and the corresponding
simulation results that are carried out on a scaled prototype are also shown.
Mitigation of Voltage Sag/Swell with Fuzzy Control Reduced Rating DVRIJERD Editor
Power quality has been an issue that is becoming increasingly pivotal in industrial electricity
consumers point of view in recent times. Modern industries employ Sensitive power electronic equipments,
control devices and non-linear loads as part of automated processes to increase energy efficiency and
productivity. Voltage disturbances are the most common power quality problem due to this the use of a large
numbers of sophisticated and sensitive electronic equipment in industrial systems is increased. This paper
discusses the design and simulation of dynamic voltage restorer for improvement of power quality and
reduce the harmonics distortion of sensitive loads. Power quality problem is occurring at non-standard
voltage, current and frequency. Electronic devices are very sensitive loads. In power system voltage sag,
swell, flicker and harmonics are some of the problem to the sensitive load. The compensation capability
of a DVR depends primarily on the maximum voltage injection ability and the amount of stored
energy available within the restorer. This device is connected in series with the distribution feeder at
medium voltage. A fuzzy logic control is used to produce the gate pulses for control circuit of DVR and the
circuit is simulated by using MATLAB/SIMULINK software.
Study on the Fused Deposition Modelling In Additive ManufacturingIJERD Editor
Additive manufacturing process, also popularly known as 3-D printing, is a process where a product
is created in a succession of layers. It is based on a novel materials incremental manufacturing philosophy.
Unlike conventional manufacturing processes where material is removed from a given work price to derive the
final shape of a product, 3-D printing develops the product from scratch thus obviating the necessity to cut away
materials. This prevents wastage of raw materials. Commonly used raw materials for the process are ABS
plastic, PLA and nylon. Recently the use of gold, bronze and wood has also been implemented. The complexity
factor of this process is 0% as in any object of any shape and size can be manufactured.
Spyware triggering system by particular string valueIJERD Editor
This computer programme can be used for good and bad purpose in hacking or in any general
purpose. We can say it is next step for hacking techniques such as keylogger and spyware. Once in this system if
user or hacker store particular string as a input after that software continually compare typing activity of user
with that stored string and if it is match then launch spyware programme.
A Blind Steganalysis on JPEG Gray Level Image Based on Statistical Features a...IJERD Editor
This paper presents a blind steganalysis technique to effectively attack the JPEG steganographic
schemes i.e. Jsteg, F5, Outguess and DWT Based. The proposed method exploits the correlations between
block-DCTcoefficients from intra-block and inter-block relation and the statistical moments of characteristic
functions of the test image is selected as features. The features are extracted from the BDCT JPEG 2-array.
Support Vector Machine with cross-validation is implemented for the classification.The proposed scheme gives
improved outcome in attacking.
Secure Image Transmission for Cloud Storage System Using Hybrid SchemeIJERD Editor
- Data over the cloud is transferred or transmitted between servers and users. Privacy of that
data is very important as it belongs to personal information. If data get hacked by the hacker, can be
used to defame a person’s social data. Sometimes delay are held during data transmission. i.e. Mobile
communication, bandwidth is low. Hence compression algorithms are proposed for fast and efficient
transmission, encryption is used for security purposes and blurring is used by providing additional
layers of security. These algorithms are hybridized for having a robust and efficient security and
transmission over cloud storage system.
Application of Buckley-Leverett Equation in Modeling the Radius of Invasion i...IJERD Editor
A thorough review of existing literature indicates that the Buckley-Leverett equation only analyzes
waterflood practices directly without any adjustments on real reservoir scenarios. By doing so, quite a number
of errors are introduced into these analyses. Also, for most waterflood scenarios, a radial investigation is more
appropriate than a simplified linear system. This study investigates the adoption of the Buckley-Leverett
equation to estimate the radius invasion of the displacing fluid during waterflooding. The model is also adopted
for a Microbial flood and a comparative analysis is conducted for both waterflooding and microbial flooding.
Results shown from the analysis doesn’t only records a success in determining the radial distance of the leading
edge of water during the flooding process, but also gives a clearer understanding of the applicability of
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gases, bio acids etc.
Gesture Gaming on the World Wide Web Using an Ordinary Web CameraIJERD Editor
- Gesture gaming is a method by which users having a laptop/pc/x-box play games using natural or
bodily gestures. This paper presents a way of playing free flash games on the internet using an ordinary webcam
with the help of open source technologies. Emphasis in human activity recognition is given on the pose
estimation and the consistency in the pose of the player. These are estimated with the help of an ordinary web
camera having different resolutions from VGA to 20mps. Our work involved giving a 10 second documentary to
the user on how to play a particular game using gestures and what are the various kinds of gestures that can be
performed in front of the system. The initial inputs of the RGB values for the gesture component is obtained by
instructing the user to place his component in a red box in about 10 seconds after the short documentary before
the game is finished. Later the system opens the concerned game on the internet on popular flash game sites like
miniclip, games arcade, GameStop etc and loads the game clicking at various places and brings the state to a
place where the user is to perform only gestures to start playing the game. At any point of time the user can call
off the game by hitting the esc key and the program will release all of the controls and return to the desktop. It
was noted that the results obtained using an ordinary webcam matched that of the Kinect and the users could
relive the gaming experience of the free flash games on the net. Therefore effective in game advertising could
also be achieved thus resulting in a disruptive growth to the advertising firms.
Hardware Analysis of Resonant Frequency Converter Using Isolated Circuits And...IJERD Editor
-LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
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exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits.
Simulated Analysis of Resonant Frequency Converter Using Different Tank Circu...IJERD Editor
LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region [5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
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Amateurs Radio operator, also known as HAM communicates with other HAMs through Radio
waves. Wireless communication in which Moon is used as natural satellite is called Moon-bounce or EME
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operated amateur HAM radio was difficult. Even with the modest setup having good transceiver, power
amplifier and high gain antenna with high directivity, VHF DXing is possible. Generally 2X11 YAGI antenna
along with rotor to set horizontal and vertical angle is used. Moon tracking software gives exact location,
visibility of Moon at both the stations and other vital data to acquire real time position of moon.
“MS-Extractor: An Innovative Approach to Extract Microsatellites on „Y‟ Chrom...IJERD Editor
Simple Sequence Repeats (SSR), also known as Microsatellites, have been extensively used as
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crucial. However, Microsatellites repeat count is compared, if they differ largely, he has some disorder. The Y
chromosome likely contains 50 to 60 genes that provide instructions for making proteins. Because only males
have the Y chromosome, the genes on this chromosome tend to be involved in male sex determination and
development. Several Microsatellite Extractors exist and they fail to extract microsatellites on large data sets of
giga bytes and tera bytes in size. The proposed tool “MS-Extractor: An Innovative Approach to extract
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data sets of human genome „Y‟. The proposed system uses string matching with sliding window approach to
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Importance of Measurements in Smart GridIJERD Editor
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grid will increase the complexity, optimization problems and instability of the system. This will lead to a
paradigm shift in the instrumentation and control requirements for Smart Grids for high quality, stable and
reliable electricity supply of power. The monitoring of the grid system state and stability relies on the
availability of reliable measurement of data. In this paper the measurement areas that highlight new
measurement challenges, development of the Smart Meters and the critical parameters of electric energy to be
monitored for improving the reliability of power systems has been discussed.
Study of Macro level Properties of SCC using GGBS and Lime stone powderIJERD Editor
The document summarizes a study on the use of ground granulated blast furnace slag (GGBS) and limestone powder to replace cement in self-compacting concrete (SCC). Tests were conducted on SCC mixes with 0-50% replacement of cement with GGBS and 0-20% replacement with limestone powder. The results showed that replacing 30% of cement with GGBS and 15% with limestone powder produced SCC with the highest compressive strength of 46MPa, meeting fresh property requirements. The study concluded that this ternary blend of cement, GGBS and limestone powder can improve SCC properties while reducing costs.
Study of Macro level Properties of SCC using GGBS and Lime stone powder
Welcome to International Journal of Engineering Research and Development (IJERD)
1. International Journal of Engineering Research and Development
eISSN : 2278-067X, pISSN : 2278-800X, www.ijerd.com
Volume 4, Issue 8 (November 2012), PP. 84-93
Soil Penetration Resistance and Its Dependence on Soil Moisture
and Age of the Raised-Beds in the Mekong Delta, Vietnam
Pham Van Quang1,2, Per-Erik Jansson1 and Le Van Khoa3
1
Department of Land and Water Resources Engineering, KTH, SE 100 44 Stockholm, Sweden
2
Department of Soil Science & Natural Resources, Faculty of Agriculture & Natural Resources,
An Giang University, Vietnam
3
Director of the Department of Research Affairs in Can Tho University, Vietnam
Abstract:––The research was conducted on 10 citrus plantations at Hau Giang province in the Mekong delta, Vietnam during
one year with a portable electronic penetrometer to understand the impact of moisture on the soil compaction. Soil
penetration resistance (PR) was measured in the depth of 0-80 cm depth and soil samples also taken at each 10 cm depth
from the soil surface to the water level for soil moisture measurement. The results showed that PR increased as a function of
raised-bed’s age and it could be reached to a high degree by soil moisture variability during the season. The sensitivity of PR
to soil moisture decreases with the age of raised-beds while the soil moisture represented an increasing tendency with the age
of raised-beds. Relationship between PR and soil moisture are explained better by the volumetric water content than the
corresponding soil water potential expressed as pF values. The measurements of soil PR determined by the previous results,
which are obtained from soil, core samples with the dry bulk density and water retention curves were calculated and
analyzed. Using the PR data will be very useful; it is a complementary and important information for identification the soil
structure and soil moisture content. Without such processing of PR measurements, the values of the PR measurements will
be limited and not indicated for soil compaction. To minify soil compaction on the raised-beds, all the pressure and
mechanical activities should not be done in the soil surface, specially in the wet condition. Organic fertilizers and Biochar
can be considered as soil conditioners and recommended to applied in orchard for improving soil properties.
Keywords:––Citrus orchard, soil strength, soil compaction, Mekong delta
I. INTRODUCTION
Soil-water-plant relationship is a dynamic system that it interacts mutually. Soil plays a vital important role as a
crucial foundation, on which the plant can coexist harmoniously with surrounding environments. Under natural conditions,
soil has a resilient capacity. However, soils are prone to the deteriorative processes, which have subjected to the soil
formation and cultural practices.
There are many soil physical properties affecting to the plant growth such as texture, structure, water retention,
hydraulic conductivity, heat capacity, thermal conductivity and soil strength. For good plant growth, it is essential that the
soil must provide a favorable physical environment for root development. Since plant root system is mostly growing in
porous media, it must therefore overcome mechanical soil resistance. Penetration resistance (PR) of soils is an important
parameter that influences to the root growth and water movement. The most common method to evaluate soil strength is by
using a penetrometer, which is characterized by the force required to advance a cone of specific base size into the soil
(Bradford, 1986). Cone penetrometers have been extensively used in agriculture and horticulture to study tillage system
(Unger and Jones, 1998), soil compaction and soil crust formation (Baumhardt et al., 2004; Jung et al., 2010; Mosaddeghi et
al., 2000; Smith et al., 1997). Studies done by Laboski et al. (1998), Lampurlanes and Cantero-Martinez (2003), Pabin et al.
(1998) and Stelluti et al. (1998) revealed strong correlations between PR and root elongation, between PR and crop yield. A
few studies related to soil science were carried out by using cone penetrometers in the Mekong delta, Vietnam (MD). Such
studies were also researched on rice-field cultivation to identify the natural and compacted layers (Khoa, 2002), and on citrus
plantations to recognize soil physical and chemical degradation with the different ages of the raised beds (Guong et al.,
2005).
Soil penetration resistance mainly depends on soil type, bulk density and soil water content (Ayers and Perumpral,
1982; Gliński and Lipiec , 1990; Henderson et al., 1988). Compaction leads to the changes in soil porosity (Alaoui and
Helbling, 2006), and consequence in variability of the pore-size distribution (Hayashi et al., 2009). Wet and dry cycles
naturally influence to the soil moisture content that affects cohesion, angle of internal fiction, compressibility and adhesion.
In the saturated soi1 condition, cohesion is at its minimum because of the presence of free water in soil pores. When soil
moisture decreases, negative water potentials develop and water held by soil particles takes action as a bonding agent,
therefore increasing cohesion. PR increases as the soil dries and decreases as the soil becomes wetter or any soil at a given
bulk density (Bar-Yosef and Lambert, 1981). In addition, bulk density may not have large changes over relatively short
periods; therefore, PR is mostly associated with soil moisture changes. To allow comparison of PR taken at the different soil
moisture contents, it is necessary to normalize PR readings to common soil moisture. A penetrometer measurement of 2 MPa
generally concerned as sufficient to impede the growth and development of plants (Taylor and Gardner, 1963). At PR larger
than 2.5 MPa, root elongation is significantly restricted (Whalley et al., 2007). However, some studies showed significantly
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2. Soil Penetration Resistance and Its Dependence on…
the higher PR values due to the influence of the soil moisture content at the time of the penetrometer readings with visually
healthy plants (Smith et al., 1997; Sojka et al., 2001; Whalley et al., 2007).
In this study, penetration resistance was used to obtain a general description of soil strength under 10 raised beds
with the different ages in the MD. Major objective was to investigate if measurements of penetration resistance can be used
to understand how soil degradation will develop during cultivations in the raised beds in the MD. The specific objectives
were (i) to describe how the relationship between PR and soil moisture that may be affected by soil compaction, (ii) to
describe the seasonality of simultaneous dynamics of PR and soil moisture, (iii) to discuss the additional value of soil PR
compared with conventional information on soil physical properties, and (iv) to provide some general guidelines for how to
counteract with soil degradation in the MD.
II. MATERIALS AND METHODS
Site description
The study was initiated in 2010 on 10 selected citrus plantations in Hau Giang province, Mekong delta, Vietnam
with the different ages as shown in Table 1 and Fig. 1. The climate is characterized by two distinct seasons, a dry season
from December to April and a rainy season from May to November. The annual rainfall ranges from less than 1000 mm to
over 1300 mm, however most of 90% rainfall concentrates in the rainy season. The mean temperature is from 23-25 oC
during the coldest months and from 32-33 oC during the warmest months. The humidity is high in the rainy season, the
highest in September (91%), and the lowest in the dry season (79 – 82%). The soil is classified as the alluvial soils (Soil
Science Department, CTU 1985-1996; Soil Survey Staff, 1996). Texture is classified as silty clay. The raised beds were
constructed by excavating and heaping up soil materials from adjacent lateral ditches to form the long raised strips that are
higher than the original ground surface. Soil layers on the raised beds were commonly arranged in the reverse order
compared to the sequence of soil master horizon in natural soils.
Figure 1. (a) Administrative map of the Mekong Delta, Vietnam (b) Map of Hau Giang Province, (c) Map showing the study
location, extracted from Google Earth.
The data collections started at the beginning of the dry season, January 2010. Soil samples were taken from each of
the raised bed for soil physical analyses at the layers of 0-20 cm and 20-50 cm depth with four replications at each study site.
Laboratory tests were also done to determine the soil physical properties; it consisted of bulk density and water retention.
Bulk density, ρb (g cm-3) was determined from oven-dry weight of 5 cm in diameter and 5 cm long undisturbed core samples
(Blake and Hartge, 1986). Soil water retention (pF curve) was experimentally determined using soil sample procedures
(Cassel and Nielsen, 1986; Klute, 1986). Undisturbed and disturbed samples were saturated with water in 48h, subsequently
using the sand box apparatus and pressure membrane apparatus (Eijkelkamp Agrisearch Equipment, the Netherlands) for a
range of suction pressures from 0 to 0.1 bar (pF: 0 - 2) and from 0.3 to 15 bar (pF: 2.5 - 4.2) respectively. Soil water
retention was determined in the laboratory with 8 pF values. Soil water retention curves were established by fitting the
pressure-soil moisture content data to the model of van Genuchten (1980).
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3. Soil Penetration Resistance and Its Dependence on…
Table 1. Ten study locations selected in Hau Giang province, Mekong delta, Vietnam
Locations Latitude Longitude Age range (years)
1 9 o 53' 44.38'' 105 o 43' 41.09'' 15
2 9 o 53' 28'' 105 o 43' 57.14'' 17
3 9 o 53' 35.74'' 105 o 43' 47.75'' 19
4 9 o 53' 31.7'' 105 o 43' 42.78'' 28
5 9 o 53' 28'' 105 o 43' 29.46'' 30
6 9 o 53' 35.7'' 105 o 43' 41.27'' 31
7 9 o 53' 29.18'' 105 o 43' 50.7'' 32
8 9o 53' 38.47'' 105 o 43' 45.34'' 33
9 9 o 54' 2.7'' 105 o 43' 49.4'' 35
10 9 o 53' 29.22'' 105 o 43' 41.16'' 37
This study used a portable electronic penetrometer, with a built-in data logger for storage and processing of a great
number of measuring data (500 measurements), developed by the Eijkelkamp Agrisearch Equipment, the Netherlands. The
penetrologger method had a measuring range of 1000 N (10 MPa). PR was measured by a load cell connected to a cone
screwed onto the bottom end of a bipartite probing rod. The cone used in this study has 60° angle and the base area of 1 cm 2.
An internal ultrasonic sensor accurately registers the vertical distance above the soil surface and load cell was used to
calculate the PR at each centimeter and the device stored data up to the depth of 80 cm in the profile. Speed penetration was
set at 1 cm s-1.
Data were periodically taken on 10 raised beds with once a week, started from 22-01-2010 to 02-06-2010 (a data
series of ten points). On each raised bed, penetrometer measurements were designed into three plots and three ‘penetrations’
were carried out to obtain a representative average result per plot automatically. At the same time as PR measurements, soil
samples were also taken from a distance within 0.1 m from the PR measurement points. Sampling depths were selected in
the following intervals, 0 to 10 cm; 10 to 20 cm; and so on down to water level. Soil samples were then taken to determine
the soil moisture by dried method at 105°C in the laboratory. The measured soil water retention characteristic curves were
used to convert the volumetric moisture content data to water potential (pF). The volumetric moisture content was calculated
from the mass moisture content and bulk density.
A subset of PR data series was extracted from the PR measurements. At the depth of 5, 15, and 25 cm from the soil
surface were considered as a representative for layer of 0-10, 10-20, and 20-30 cm respectively. Based on the PR data series
and according to the soil moisture data set, the relationship between PR and soil moisture was analyzed by using linear
regression method. The same procedure was also applied to determine the relationship between PR and pF values. On the
bases of these regression equations, PR was recalculated from the soil moisture and/or pF values for further analyses.
Comparisons of the differences between the raised beds were determined by using the t-test with 0.05 significant levels.
III. RESULTS
Bulk density varied in the range of 0.76 - 1.18 g cm-3 and 0.85 - 1.24 g cm-3 for topsoil and subsoil respectively
(Table 2). Bulk density value of the subsoil was slightly higher than that of topsoil. There are the differences significantly at
0.05 level between the raised beds and the increasing trend with the age of raised beds was found for the subsoil. The similar
trend was also seen for the topsoil. However, there are no the differences significantly at 0.05 level exception for the 15-
year-old raised bed.
Table 2: Bulk density and fitted van Genuchten parameters of soil moisture characteristic for topsoil and subsoil – values in
the parenthesis
Age of raised Bulk density Fitted
bed parametersa
-3
(year) (g cm ) θs θr α n
15 0.76 a (0.85 d) 62.3 (61.0) 0.017 (0.004) 0.010 (0.009) 1.18 (1.17)
17 1.02 b (1.09 bc) 52.1 (49.2) 0.040 (0.052) 0.011 (0.004) 1.13 (1.13)
19 1.02 b (1.13 abc) 51.7 (48.1) 0.037 (0.040) 0.011 (0.004) 1.13 (1.14)
28 1.16 b (1.20 ab) 48.3 (45.9) 0.040 (0.045) 0.005 (0.004) 1.13 (1.14)
30 1.09 b (1.15 abc) 47.2 (48.0) 0.046 (0.040) 0.006 (0.004) 1.13 (1.15)
31 1.17 b (1.12 abc) 49.9 (46.9) 0.049 (0.043) 0.008 (0.004) 1.13 (1.14)
32 1.11 b (1.17 abc) 51.1 (48.2) 0.040 (0.042) 0.009 (0.005) 1.14 (1.15)
33 1.18 b (1.16 abc) 48.9 (46.7) 0.071 (0.073) 0.009 (0.004) 1.14 (1.15)
35 1.02 b (1.24 a) 46.1 (45.5) 0.099 (0.095) 0.006 (0.005) 1.12 (1.14)
37 1.14 b (1.03 c) 48.4 (54.8) 0.063 (0.074) 0.005 (0.005) 1.14 (1.16)
Within a data column, numbers are followed with the same letter show no significant difference at 5%; a Units of
parameters: θr, residual water content (cm3 cm-3); θs, saturated water content (cm3 cm-3); α, inverse of the air entry potential
(cm-1); n, empirical constant affecting the shape of the retention curve.
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4. Soil Penetration Resistance and Its Dependence on…
Soil water retention curves (SWRC) of the topsoil and subsoil in the raised beds are shown in Fig. 2. The curves
had rather gentle shape as the volumetric water content gradually changed with soil pressure heads but the different shape of
curve among the sites as well as at the different soil depths within each site are found. The shape of the SWRC is
intrinsically related to the pore-size distribution. Compaction energy and soil structure influenced the shape of the SWRC for
fine-textured soils (Vanapalli et al., 1999). Water retention is higher in the wet range but slightly lower in the dry range for
topsoil compared to subsoil (Table 2, Fig 2).
The residual water content, θr, remains at a very high pressure. It is directly related to micro-pores and is
considered as unavailable to the plants. The θr generally tended to increase with age of the raised beds (Table 2). This
implied that the greater soil water retention, the greater proportion of micro-pores are. The increasing of micro-pore
proportion can be used as an indicator of soil compaction. The air-entry pressure (1/α) corresponded to the matric suction
required to remove water from the largest pores, which is also related to soil pores forming the continuous network of the
flow paths within the soil (Assouline et al., 1998).
Figure 2. Soil water retention curves of soil profile at the different ages of raised beds at topsoil (solid blue line) and subsoil
(dash red line) corresponding to the triangle and square symbols for measured pF points
Soil penetration resistance (PR), which plotted against soil depth under the different raised beds, is shown in Fig.
3. The results showed the average values which are taken overall the observed period of 22-01 to 2-06-2010. In general, the
variability of the PR regularly increased from the soil surface and reached maximum value at 10 cm within the depth of 25
cm then it decreased in the depth of 25 – 40 cm and again PR increased below 40 cm. The PR values changed in the range of
0.13 - 3.05 MPa with the confident intervals from 0.03 to 0.52 MPa in 60 cm the soil depth of profile (Fig. 3).
Figure 3: Penetration resistance plotted against soil depth at all the observed period of 22-01-2010 to 02-06-2010. Solid-
line: average value and dot-line: confident intervals at 95%.
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5. Soil Penetration Resistance and Its Dependence on…
Figure 4 showed the general variation of soil water content and PR over the observed period of 22-01 to 02-06-
2010. These values are the average ones, they are obtained from the data set of 10 raised beds, on soil water content and PR
at three soil depths. The lowest water content of 30.7% found in the top 10 cm depth and the highest of 41.7% determined in
the layer of 20-30 cm depth corresponding to PR of 2.5 MPa and 1.7 MPa respectively. The variation for both soil water
content and PR value is higher in the top layers compared to that of the deeper layers.
Figure 4: Average soil water content (θ, vol-%) and penetration resistance (PR, MPa) at 10 raised beds over the observed
period of 22-01 to 02-06-2010 for three soil layers.
Average PR calculated from the PR measurements at the soil layers of 0-10 cm (layer 1), 10-20 cm (layer 2) and
20-30 cm (layer 3) for the period of 22-01 to 02-06-2010 is shown in Figure 5. The highest PR obtained at all three layers is
measured on the 35 year old raised bed and the lowest PR is found on 15 year old raised bed, exception for 28 year old
raised bed.
The increasing trend with age of the raised beds is revealed, and the changing rate of the PR against age of the
raised beds (slope coefficient of the regression equation) increased about 42% for layer 1 compared with layer 2 and 44% for
layer 1 compared with layer 3. However, the increase is not significant for layer 2 compared with layer 3 (Fig. 5). PR values
decreased with the soil depth; however, there are no statistical significant differences of the mean value. The PR, that is
greater than 2.5 MPa, is found at the 30, 31, 32, 33, 35 and 37-year-old raised beds for layer 1, at the 31, 32, 33, 35 and 37-
year-old raised beds for layer 2, and at the 33, 35 and 37-year-old raised beds for layer 3 (Fig. 5).
Figure 5: Average penetration resistance at the different age of the raised beds and soil depths on all the observed period of
22-01-2010 to 02-06-2010. Red-dash-line: critical PR of 2.5 MPa.
88
6. Soil Penetration Resistance and Its Dependence on…
Volumetric water content (%) and pF values of soil layers of 1, 2, and 3 at the different raised beds are presented
in Fig. 6 and Fig. 7. Average soil moisture varied from 29.5 to 48.0%, correspondingly to the pF value of 3.7 and 1.9. Soil
moisture in layer 1 is significantly (p < 0.05) lower than that of the layer 3; but there are not significant differences between
layer 1 and layer 2 as well as layer 2 and 3. For soil water retention (pF values), there are not significant differences between
layer 1 and layer 2 but there are significant differences between layer 1 and layer 3 as well as layer 2 and layer 3.
Figure 6: Volumetric soil water content (%) at the different raised beds for three soil layers.
Figure 7: pF values at the different raised beds for three soil layers.
The slope coefficients increased with the soil depth as well as with age of the raised beds (Fig.8). The relationship
between a1 (from PR = a1θ + a0) and age of the raised beds is significantly consistent with linearity (R2> 0.7). The plot of a1
versus age becomes more scattered for deeper layers, this is reflected by the decrease in R 2 (Fig. 8). In contrast to soil
moisture, the slope coefficients (from PR = a1pF + a0) decreased with soil depth as well as with age of the raised beds (Fig.
8); however, the plot of a1 versus age of the raised beds is more dispersed.
89
7. Soil Penetration Resistance and Its Dependence on…
Figure 8: Slope coefficient plotted versus age of the raised beds on different soil layers.
The recalculations of PR based on regression equations (PR = a1θ + a0) correspondingly using soil moisture values
at pF of 2, 2.5, 3 and 4.2 are presented in Fig. 9 for layer 1, 2, and 3. The results showed the increasing trend of PR with age
of the raised beds on whole soil profile. PR values are higher corresponding to the lower in soil moisture. Similarly, the
results of PR by using PR = a1pF + a0 with pF value of 2, 2.5, 3 and 4.2 are not significant differences compared to PR = a 1θ
+ a0.
Figure 9: Soil penetration resistance recalculated by PR = a1θ + a0 (θ estimated from water retention curves at pF value of
2, 2.5, 3 and 4.2)
90
8. Soil Penetration Resistance and Its Dependence on…
IV. DISCUSSIONS
The role of soil moisture
The PR-intercept (a0) can be interpreted as the value predicted for PR if θ = 0 (or pF = 0). It is expected to have the
average PR for a very dry soil (θ = 0) or fully saturated condition (soil pressure head is 1 cm water). However, this is an
extrapolation from the current stage of soil moisture to a complete dry or wet soil condition. If the ultimate dry nor wet soil
is never reached, these extrapolations are mostly of theoretical interest. It just anchors the regression line in the right place.
In this study case, it is easy to see that ultimate dry condition may never occur in the real field soil conditions and then the
intercept has no real interpretation itself. Moreover, the definition of pF value is the base 10-logarithm function of the soil
pressure head expressed in cm of water. Therefore, pF value will be infinitive when soil pressure head approaches to 0.
The slope coefficient (a1) gives the average change in PR with respect to θ (or pF values). The magnitude of a 1 (large or
small) indicates the change rate of PR and the sign of a1 suggest the increase of PR (positive) or the decrease of PR
(negative). The greater the a1 (absolute value), the more influence the θ (or pF value) has on the PR, and the more change of
PR associated with a unit change in θ (or pF value). In this study, the negative a1 for PR versus soil moisture is obtained,
while the opposite situation is found for PR versus pF values - representing soil water retention. This suggested the PR
decreased with increasing soil moisture and the PR increased with decreasing pF value. The results demonstrated that the
less change in PR associated with a change in θ (or pF values) when the raised beds became older. This indicated that the
young raised beds have been easier to disturb, while the old ones are in a mode of more inert system with smaller sensitivity.
In other words, the soil is more compacted with age of the raised beds. We can see that both of predictors (θ and pF value)
showed the same phenomena but in the different ways. Based on the obtained results, PR is predicted by θ and pF value is
not significantly different. So, the pF value and either θ can be used to predict PR. However, it will be easier to obtain the θ
than pF value. Moreover, it was interesting that slope coefficient plotted against age of the raised beds on the different soil
layers, drawn from regression equations PR = a1θ + a0 and PR = a1pF + a0 (Fig. 8). The results showed that the explanations
based on θ are better than pF value. This suggested the PR (a1θ + a0) could predict the PR more credible than using PR (a1pF
+ a0).
Soil water content was found to be an important factor affecting to the PR. Compressibility is also closely related
to soil water content (Larson et al., 1980). The slower drying is maybe a phenomenon of a poor plant development because it
may restrict plant root growing to deeper layer and soil is poor aeration. Nevertheless, it may also be the sign of a very
efficient soil that stores high amount of water. Soil water content, which plant growth is at a maximum, is near field capacity
condition - soil pressure head at pF of 2.5 or -30 kPa, where the integrated supply of both oxygen and water are the most
favorable (Foth, 1990; Lal and Shukla, 2004). Moreover, plant root will be dramatically affected if soil is compacted that
means the soil strength exceeds the root penetration capacity (Jarmillo-C et al., 1992). Field measurement of the PR is the
indicator to characterize soil compaction. Lutz et al. (1986) studied the relationship between citrus root growth and soil
physical conditions documented that 1.5 MPa is the maximum soil strength restricting root growth. As the results showed in
Fig. 9, it can be seen that the PR reached to 2 MPa over the top 30 cm depth for starting from 30 year old raised beds at the
field capacity condition and PR is able to be higher when soil becomes drier. Since soil water dynamics is seasonally
dependent in the MD with 2 major periods – dry and wet. Water acts as a lubricant, so soil particles are easily rearranged and
squeezed together more tightly at wet than under dry conditions. These directly have the effect on soil water regime, which is
combined with the phenomena of swelling and shrinking limit, may contribute to the process of erosion and compaction. In
addition, cracks are normally formed during the dry periods. The desiccation cracks are developed that may cause the
increase in the hydraulic conductivity of several orders of the magnitude (Albrecht and Benson, 2001; Boynton and Daniel,
1985; Rayhani et al., 2007). These cracks also create the weak zones in a soil body leading to reduce overall the mechanical
strength and bearing capacity and to increase the compressibility and therefore it considerably affects stability of the soils
(Bagge, 1985). Soil particles may be detached from a soil mass along the surface of soil cracks and carried off by flowing
water because of rainy or irrigation. It depends on the velocity of water flow that the amount of the soil loss manifests itself
in various mechanisms such as suffusion, erosion, and clogging. These processes have occurred over long time; whereas
suffusion or erosion takes place at an interface between two different materials, clogging is a process that works in the
direction of stability. Finer particles position themselves in the soil pores between larger particles and/or in the soil cracks
resulting in the increase in soil strength. The clogging process could be considered as one mechanism that could have
promoted to the stability of soils, since their deposition and hence increase in soil strength. This could be a possible reason to
explain the PR of the old raised beds is higher than the young raised beds as revealed by regressing. The arrangement of the
soil particles through erosion over a long time caused the changes in soil aggregates and soil structures with the less of finer
particles as an adhesion agent. These actions have made the declination of soil quality.
As discussed above, it represented that the old raised beds having a tendency of soil degradation, which is
attributed by the higher values of the PR at the same soil moisture. These results also strengthened the previous studies
related to soil compaction which are evidenced by some soil properties such as the increasing of bulk density, the decreasing
of hydraulic conductivity and the lowering of soil organic matter. Using the electric penetrometer as a handy tool to keep
away from many drawbacks of sampling and laboratory tests, ant it has become a widely accepted means for the in-situ
properties. Penetrometer is easy to use and can collect soil information without disturbing the ground like bulk density does
(Chacalo and Grabosky, 2000). The PR equipment applied is suitable in the MD under monsoon climate of the tropics.
Based on the data recorded by PR measurements and the reasons caused to soil compaction, the solutions for soil restoration
can be precisely recommended for soil management. With this study, mechanical impacts during cultivation and the elluvial
and illuvial soil process are the main factors creating the compaction in situ. Under the condition, PR equipment can not be
purchased, soil porosity is usually used as the principal indicator for soil compaction.
Many factors directly or indirectly affect to the plant growth in which soil compaction is specially interested. As
mentioned above, soil compaction is characterized by the PR that has limited to effective rooting depth. If the soil status is
too weak, anchor capacity of plant roots will not be adequate to withstand the forces of wind and water. On the other hand, if
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9. Soil Penetration Resistance and Its Dependence on…
it is too strong, the plant roots will not have the required strength to penetrate to the soil matrix. The soil of raised bed has
annually tolerated to the wet and dry periods. In the flooding period, the roots are not able to penetrate to deeper layers due
to the restriction of water level, while soil strength may reach over the critical limit for developing of the roots during the dry
season.
With respect to the management practices, soil strength can be moderated by inputting the organic materials such
as mulches, composts or covering by crop pattern to improve the stability of soil aggregates and to develop the soil macro-
structures. Gypsum can be applied to stabilize the soil aggregates and micro-structure for preventing the clay dispersion.
Excessive tillage or soil preparation done under the wet condition can break down or compact both the macro and micro-size
of the aggregates leading to hardsetting and crusting at the surface soils. Biochar can be considered as another soil
conditioner for improving soil properties.
V. CONCLUSIONS
The increasing of soil penetration resistance with age of the raised beds could not be limited by the higher soil
moisture content. The sensitivity of PR equipment to soil moisture decreases with age and simultaneously the soil moisture
tended to increase with the age of raised beds. Irrigation will not be the appropriate mitigation method in this case; due to it
will also decrease the air space in soil porosity.
The measurements of soil penetration resistance illustrated the picture, which are previously given by
determination of dry bulk density and water retention curve. The penetration measurements are however, much easier since
it is non-destructive and it can be repeated at many positions within a short period of time.
Soil penetration resistance measurement combined with soil water content can be used to identify the soil quality
in term of the constraints for root growth. Based on the results and linear relationship, the highest proportion of the total
variation of the PR can be explained by soil water content, it is around 70%, indicating that there are at least 30% of the
uncertainties involved. The uncertainties may come from two main sources comprising both of PR and soil water content
measurements.
The best results can be obtained if soil water content measurements are simultaneously taken place on the same PR
measurement points with the same resolution readings.
ACKNOWLEDGEMENTS
We greatly appreciate to Mr. Ngo Xuan Hien, Section of agriculture and rural development, Chau Thanh district,
Hau Giang province in Vietnam for helping and encouragement during the fieldwork activities. We thank all the local
farmers for their kindly support at the study locations. We also thank Mr. Huynh Ngoc Duc and Mr. Pham Xuan Phu for
their assistance during data collection. College of Agriculture and Applied Biology at Can tho University in Vietnam are
gratefully acknowledged with the facility support. Last but not least, deeply thanks to Prof. Per-Erik Jansson and Dr. Le Van
Khoa for their kind advices and comments during the study.
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