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UNIT-4 Managing soil and land Ch-13 Conserving soilErosion controlErosion control is the practice of preventing or controlling wind or water erosion in agriculture, landdevelopment and construction. Effective erosion controls are important techniques in preventing waterpollution and soil loss.Erosion control techniques-Terraces are used in farming to cultivate sloped land. Graduated terrace steps are commonlyused to farm on hilly or mountainous terrain. Terraced fields decrease erosion and surface runoff,and are effective for growing crops requiring much water, such as rice.Terraced paddy fields are used widely in rice farming in east, south, and southeast Asia, as wellas other places. Drier-climate terrace farming is common throughout the Mediterranean Basin,e.g., in Cadaqués, Catalonia, where they were used for vineyards, olive trees, cork oak, etc., onMallorca, or in Cinque Terre, Italy.Contour plowing (or contour ploughing) or contour farming is the farming practice ofplowing across a slope following its elevation contour lines. The rows form slow water run-offduring rainstorms to prevent soil erosion and allow the water time to settle into the soil. Incontour plowing, the ruts made by the plow run perpendicular rather than parallel to slopes,generally resulting in furrows that curve around the land and are level. A similar practice iscontour bunding where stones are placed around the contours of slopes. Contour plowing terracing
Contour bunding wind-breaks A windbreak or shelterbelt is a plantation usually made up of one or more rows of trees orshrubs planted in such a manner as to provide shelter from the wind and to protect soil from erosion.They are commonly planted around the edges of fields on farms. If designed properly, windbreaksaround a home can reduce the cost of heating and cooling and save energy. Windbreaks are alsoplanted to help keep snow from drifting onto roadways and even yards. Other benefits include providinghabitat for wildlife and in some regions the trees are harvested for wood products. Dryland farming is an agricultural technique for non-irrigated cultivation of drylands. It is a practice of growing profitable crops without irrigation in areas which receive an annualrainfall of 500mm or even less. Dry land being water deficient are characterized by high evaporation rates, high temperatureduring summer, low humidity and high run-off and soil erosion. Soil is saline and low in fertility.Uncertainity of rainfall causes partial or complete failure of cropswhich leads to famines. Dry farming Tree plantingTree planting is the process of transplanting tree seedlings, generally for forestry, landreclamation, or landscaping purposes. It differs from the transplantation of larger trees inarboriculture, and from the lower cost but slower and less reliable distribution of tree seeds.Planting trees is an easy and effective way to beautify your property, provide shade in summer and wind protection in winter and enhance privacy all while increasing real
estate values at the same time. Since a tree is such a visible part of the landscape care must be taken to ensure proper growth conditions are maintained. A tree is far more difficult - and expensive - to replace, once mature in the landscape, than most shrubs. However, with some advance planning, trees too can be easily maintained.A gully is a landform created by running water, eroding sharply into soil, typically on a hillside.Gullies resemble large ditches or small valleys, but are metres to tens of metres in depth andwidth. When the gully formation is in process, the water flow rate can be substantial, whichcauses the significant deep cutting action into soil.Gullying or gully erosion is the process by which gullies are formed. Hillsides are more prone togullying when they are cleared of vegetation, through deforestation, over-grazing or other means.The eroded soil is easily carried by the flowing water after being dislodged from the ground,normally when rainfall falls during short, intense storms such as during thunderstorms. Gulliesreduce the productivity of farmland where they incise into the land, and produce sediment thatmay clog downstream waterbodies. Because of this, much effort is invested into the study ofgullies within the scope of geomorphology, in the prevention of gully erosion, and in restorationof gullied landscapes. The total soil loss from gully formation and subsequent downstream riversedimentation can be sizable. GullyOrganic fertilizers are naturally occurring fertilizers (e.g. compost, manure).Naturally occurring organic fertilizers include manure, slurry, worm castings, peat, seaweed,humic acid, and guano. Sewage sludge use in organic agricultural operations in the U.S. has beenextremely limited and rare due to USDA prohibition of the practice (due to toxic metalaccumulation, among other factors).Processed organic fertilizers include compost, bloodmeal, bone meal, humic acid, amino acids,and seaweed extracts. Other examples are natural enzyme-digested proteins, fish meal, andfeather meal. Decomposing crop residue (green manure) from prior years is another source offertility.
Organic fertilizers also re-emphasize the role of humus and other organic components of soil,which are believed to play several important roles: Mobilizing existing soil nutrients, so that good growth is achieved with lower nutrient densities while wasting less Releasing nutrients at a slower, more consistent rate, helping to avoid a boom-and-bust pattern Helping to retain soil moisture, reducing the stress due to temporary moisture stress Improving the soil structure Helping to prevent topsoil erosion (responsible for desertfication and the Dust bowlOrganic fertilizers also have the advantage of avoiding certain problems associated with theregular heavy use of artificial fertilizers: The necessity of reapplying artificial fertilizers regularly (and perhaps in increasing quantities) to maintain fertility Extensive runoff of soluble nitrogen and phosphorus, leading to eutrophication of bodies of water (which causes fish kills) Costs are lower for if fertilizer is locally available[ Land management is the process of managing the use and development (in both urban andrural settings) of land resources. Land resources are used for a variety of purposes which mayinclude organic agriculture, reforestation, water resource management and eco-tourism projects.Changes in land use such as deforestation and soil degradation—two devastating effects ofunsustainable farming practices—emit large amounts of carbon into the atmosphere; land-usechange alone is responsible for approximately 20 per cent of global emissions of carbon dioxideeach year. These unsustainable practices also have profound implications for the health and well-being of local communities and the ecosystems in which they reside.Yet the land-use sector also has the potential to play a large, positive role in the global effort toaddress climate change—both by reabsorbing or preventing the release of carbon dioxide and bybuilding robust ecosystems that support adaptation to the impacts of climate change. Sustainableland-management practices such as conservation agriculture, intercropping and sustainableforestry can provide multiple benefits such as reducing erosion, building soil fertility andstructure, improving water quality and buffering against drought.These improved land-management practices are also cost-effective options that could take effectvery quickly. Given that it will take time to transform our energy systems and infrastructure toachieve deep reductions in greenhouse gas emissions, actions in the land-use sector could have asignificant role in meeting short- to medium-term greenhouse gas mitigation commitments. Andbecause the largest and most cost-effective mitigation opportunities in the agriculture andforestry sectors are in developing countries, these countries are likely to play a prominent role inefforts to reduce greenhouse gas emissions through land management.The work of the International Institute for Sustainable Developent (IISD) at the intersection ofland use and climate change explores ways to best achieve the mitigation and vulnerability-
reduction potential of this sector through the development of an effective international climateregime. Our work focuses on strengthening the capacity of developing-country negotiators andpractitioners to effectively engage in the decisions that are shaping the emergence of reducingemissions from deforestation and degradation in developing countries (REDD). IISD is alsoundertaking analysis of how agriculture can be most effectively included in the global climateregime.Our work on these issues complements and supports the research we are undertaking related tothe emergence of a North American approach to energy and climate policy, reflecting the factthat land management is also an important issue in Canada, the United States and Mexico. Forexample, Albertas emission trading system includes offsets in the agriculture and forestrysectors, and Canadas emerging federal system is expected to include offsets in the land-management sector. As well, our work in the Canadian prairies continues to explore how tocreate a sustainable system of prairie agriculture resilient to environmental and economic shocksand stresses. 1) Vegetative PracticesSoil-conserving and soil-improvement crops prevent or retard erosion. They maintain rather thandeplete soil organic matter, improve soil structure and tilth, and increase water intake andproductivity of the soil. Grasses and legumes are two such crops. Recommended vegetativepractices are : 1. Continuous cropping - use only on Class I land. 2. Crop rotation: one year of hay every third year - use on Class II land. 3. Crop rotation: two years of hay in every four years - use on Class III land. 4. Long term grass rotation with three or more years of hay between crops - use on Class IV land. 5. Permanent pasture - Class V & VI land. 6. Permanent woodland - Class VII. 7. Wildlife or recreation area - Class VIII. 8. Do not burn crop residue - Class I through IV. 9. Crop production management and may include: residue management, cover crops, grassed water ways. Classes I through IV. 10. Pasture management - may include reseeding, fertilizer and lime applications, clipping or mowing, pasture renovation. Class V and VI land. 11. Protect from burning - grass, brush or timber. Class V, VI, VII and VIII. 12. Controlled grazing and may include deferred grazing, rotational grazing, and proper stocking - Class V & VI land. 13. Plant recommended trees including windbreaks or woodland planting. Class VII and VIII. When used on Class VII, check number 14. 14. Harvest trees selectively - Class VII only. 15. Protect from grazing - Classes VII and VIII. 16. Conservation plantings - shrubs and vines for erosion control, wildlife cover - Classes VII and VIII.
(2) Mechanical PracticesThese practices are needed to correct problems with the land so that it may be used according toits most intensive use. Controlling undesirable plant species is often necessary to improve growthof desirable plants. Certain mechanical and conservation practices reduce the potential forerosion, while others correct erosion or drainage problems. 17. Control brush and trees - the use of herbicides or cutting to remove undesirable brush or trees. Should not be marked if brush can be removed by normal plowing or clipping with a cutter bar (stem diameter 1 inch or less). Class I through VI. 18. Farm on contour - plowing the whole field on the contour or at right angles to the slope. Use only on fields 2 acres or smaller having a slope of 3% or greater. 19. Contour strip cropping - alternating sod strips with row crops grown on the contour reduces wind and water erosion. Use only on fields greater than 2 acres having a slope of 3% or greater. 20. Build diversion ditch - a shallow channel built on a gently grade, across a slope, to intercept water from the slope above and carry it to a safe outlet. Mark only when "overhead water problem" is indicated on field sign. Build a diversion ditch should be marked only on Class II to VI land. 21. Install drainage system - to remove excess surface or subsurface water. Use only on imperfectly or poorly-drained soils. Classes III and IV. 22. Control gullies - one or more conservation practices that will adequately control runoff and erosion. Gullies are defined as 8 inches across and 6 inches deep, and actively eroding. 23. No mechanical treatment needed. This box must be marked when no mechanical practices are necessary.Conserving soil and water togetherStrip cropping is a method of farming used when a slope is too steep or too long, or when othertypes of farming may not prevent soil erosion. Striely sown crops such as hay, wheat, or othersmall grains with strips of row crops, such as corn, soybeans, cotton, or sugar beets.Strip cropping helps to stop soil erosion by creating natural dams for water, helping to preservethe strength of the soil. Certain layers of plants will absorb minerals and water from the soil moreeffectively than others. When water reaches the weaker soil that lacks the minerals needed tomake it stronger, it normally washes it away. When strips of soil are strong enough to slow downwater from moving through them, the weaker soil cant wash away like it normally would.Because of this, farmland stays fertile much longer.Strip - cropping to control soil erosion caused by runoff derives its effectiveness mainly fromfollowing two factors:a) Reducing the runoff flowing through the close - growing sod strips.b) Increasing the infiltration rate of the soil under cover condition.
Strip croppingtree crops are any edible fruit, nut or legume that can serve as food for humans, livestock, orwildlife. In the context of northern temperate climates, this means the crops of hardy cultivars ofcommercial orchard tree species from further south and west in this country and from similarclimates in other parts of the world. It also means the crops of improved varieties of native treespecies that have not yet been developed for commercial use.Non-traditional examples of the first category would be Chinese chestnut, Persian walnut,European filbert/hazel, Japanese walnut (heartnut), pecan and almond. Examples of the secondcategory would be black walnut, butternut, hickory, persimmon and pawpaw. There are alsohybrid trees such as Chinese/ European chestnut, European/American hazels andbutter/heartnuts.Figure 1. Some northern nuts that can be grown in zones 5-7 in North America. Can you namethese nuts? Answers at the end of this paper. Photo by Dr Lawrence MacDaniels.