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soil fertility and management.pdf
- 2. What is soil ‘Soil’ is the upper layer of earth that may be dug or flowed and in which plants grow. Soil compost of four major components Air Water Minerals Organic matter Soil is providing mechanical supports to plants, its serves as a reservoir (a place where something is kept in store) of nutrients – both the naturally occurring and those supplied by fertilizer.
- 3. Procedures and practices for maintaining and sustaining the fertility of soil •Conventional farming system. • utilizes synthetic fertilizers as a major source of nutrients •Organic crop production. • Depends on OM sources and microbial inoculants/organism for sustaining soil health and supplying nutrients to the plants
- 4. 16 ESSENTIAL PLANT ELEMENTS MACRO-ELEMENTS • Nitrogen • Phosphorus • Potassium • Calcium • Sulfur • Carbon • Hydrogen • Oxygen MICRO-NUTRIENTS • Iron • Manganese • Copper • Boron • Molybdenum • Chloride • Zinc
- 5. Nitrogen •most limiting and is required by most crops in great amounts •necessary in chlorophyll production • Chlorophyll is needed to produce food for growth and nutrient uptake •also a component of amino acids, a building block of proteins.
- 6. Nitrogen •Nitrogen supplied by synthetic fertilizer is highly prone to leaching or volatilization, particularly in soils with low or negligible organic matter or low nutrient holding capacity. •Synthetic nitrogen sources are not allowed in organic farming
- 7. Nitrogen For efficient soil nitrogen management the following are suggested: • incorporate farm residues 2-4 weeks before land preparation to avoid subjecting the plant to "nitrogen hunger" • practice intermittent flooding and draining in rice to reduce leaching and other losses • maintain a soil organic matter content of 2% or more to increase nutrient holding capacity of the soil • avoid a very dry soil condition to enhance microbial growth and activity
- 8. PHOSPHORUS • Essential in root growth and development in energy transport in plants. • Encourages flowering and ripening of seeds. • Deficiency of phosphorus in plants is easily diagnosed by the purplish coloration of the leaves, which in extreme level leads to death. • Among the essential nutrients, phosphorus is the most affected by soil pH.
- 9. PHOSPHORUS Ways to improve soil P availability and sequestration: • Grow deep-rooted crops on perimeter of the farm • Combine crops of different families in a cropping mix • Maintain soil pH of 6-6.5 • Augment soil P availability by using rock phosphate in combination with organic fertilizers or compost • Employ mulching to conserve moisture and as source of organic matter. • Improve the growing conditions for mycorzzhia by planting trees around farm.
- 10. POTASSIUM • Unlike other elements, K apparently does not form an integral part of protoplasm, fats, and cellulose. • Its role is more of catalytic in nature such as in carbohydrate metabolism and starch synthesis and breakdown; nitrogen metabolism and protein synthesis and in stomata movement and water relations. • It is also known for its ability to develop resistance to diseases in plants. • High in clayey soils. • Its deficiency results in a premature death of older plant parts first.
- 11. POTASSIUM Ways to improve K level in soils: • Incorporate crop residues (especially straw) and animal manures in the soil after harvest. • Provide permanent plant cover during rainy period (wet season) to avoid leaching losses. • Increase the humus content of the soil through application of compost or organic fertilizers • Employ mulching • Incorporate carbonized rice hull.
- 13. Fertilizer •A fertilizer is any subtance that is added to soil or to the plant (foliar) to supply elements required in plants. •Ex. 14-14-14, Urea (46-0-0), 16-20-0
- 14. Organic Fertilizer •This is define as any product of plant or animal origin that has undergone substantial decomposition through biological, chemical or any other process where the original materials are no longer recognizable. •Ex. Compost, vermicompost, FFJ
- 15. Good quality organic fertilizer •Free from chemical fertilizers, any pathogens •Soil like texture •Contains not less than 20% organic matter •Can supply nutrients to plant.
- 17. Synthetic or Chemical Fertilizers • Substance that supplies one or more nutrients, which are produced through chemical process. They usually contain high amount of nutrients and dissolve in water. • Synthetic fertilizers are undeniably responsible for large increases in the yields of crops during the advent of the “Green Revolution”. • It was contributed to the boosting of crop production that eventually saved human from hunger.
- 19. Soil Organic Matter •In healthy Agricultural soils, the solid material (approximately 95-98%) is mineral nature. •OM consists primarily of decayed or decaying plant and animal residues and is a very important Soil component. •SOM is a living component of the soil because it is the seat of microorganisms responsible for many biological transformations in soils.
- 20. •SOM serves as the main pool of nutrients for crops aside from symbiotic and non symbiotic N fixation. •SOM contains about 5% N however, this is not readily Available to plants because it is tied up in organic compounds.
- 21. Most common sources of OM in the farm: •Crop residues after harvest •Animal manures •Green manure planted in rotation either as legume forage (Centrosema) or edible legumes (mungbean) •Compost •Household wastes
- 22. •Even in ancient agriculture, continuous Cropping without addition of manures (animal or green manures) fail to produce satisfactorily.
- 23. Practices that will Reduce Losses of SOM •Rotate diverse crops with high biomass •Use cover crops or close-ground growing crop •Reduce tillage •Practice rotational grazing •Use manure and crop residues •Do not burn crop residues
- 24. Organic approach of managing soil fertility • Provide a more balanced and continuous supply of nutrients. • Improve soil aeration. • Increase water infiltration and water storage capacity. • Improve soil tilth by enhancing soil aggregate stability. • Decrease soil erosion losses due to better soil aggregation. • Increase the soil nutrient holding and exchange capacity. • Promote growth of microorganism.
- 25. Disadvantage • Acidification of the soil particularly due to heavy application of N- containing fertilizers. • Heavy application of N- containing fertilizers pose problems of high nitrate accumulation in plants. • Sole use of fertilizers containing only NPK results on deficiency of other nutrients particularly micronutrients due to continuous crop removal without replacement. • Inhibit proliferation of N- fixing microorganism in the soil due to excess N supply. • Deprive the soil of organic matter build – up, resulting in the destruction and degradation of soil.
- 26. Multicropping •as opposed to monocropping is the growing of several crops/species in the same piece of land at the same time or in sequence within a year. There are several types of multicropping: intercropping, multistorey planting, relay cropping, and crop rotation.
- 27. Intercropping •This is the growing of two or more crops in alternate rows in the same piece of land in the same season per year. •The crops are of different family and are supposed to receive benefits from their association. Examples are corn + mungbean intercropping, corn+ peanut intercropping.
- 29. Multistorey Planting •In this system, three or more crops of varying depths of root proliferation are grown in storey fashion. Crops consist of perennials and annuals. •Smaller crops are supposed to have some degree of tolerance to shading.
- 31. Multistorey Planting •Examples are mixtures of papaya+corn+legumes+ crucifers (lowland cropping system) with botanical plants around the perimeter of the farm; ‘lanzones’+coffee+pineapple+ginger (upland/highland cropping system) with botanicals in the perimeter of the farm.
- 32. Relay Cropping •This is the planting of crop even before the harvest of the main crop. The most common of this type is the rice-mungbean relay cropping. •The mungbean is usually planted 3-5 days before the rice crop is harvested and when the soil is still moist.
- 33. Relay Cropping •The objective is to take advantage of the residual moisture and nutrients from the soil particularly in rainfed areas. Mungbeans are inoculated with Rhizobium for purposes of N fixation.
- 35. Green Manures • Although there is no record when man started using synthetic fertilizers, the value of green manure in enriching the soil was mentioned in Old testament. • The best legumes for enriching the soil are field beans and the most common is mungbean. • Green manure are grown and turned under before seed maturity • At that stage, the plants have accumulated maximum biomass and nutrients that mineralize and become available to the plant at a faster rate
- 37. Benefits from Green Manuring •Enhance soil aggregation and granulation brought about by root penetration. The roots serve as channel for water infiltration •Green manure are stablished at higher population, three times more than the population intended for economic product. Hence, these crops are effective as weed control.
- 38. •Green manure legumes enrich the soil not only with organic matter but with nitrogen through symbiotic nitrogen fixation. •Green manure can be used as fodder plants or even to provide food for human consumption.
- 40. Nitrogen Fixation • The conversion of free nitrogen into nitrogenous salts to make it available for absorption of plants. • Nitrogen Fixation in soils is also brought about by certain free-living organisms to include blue green algae and bacteria. • * Clostridium, Azotobacter, and Azospirilium.
- 42. Types of Nitrogen Fixation • 1. Non-Biological fixation - The micro-organisms do not take place. - Found in rainy seasons during lightning. • 2. Biological fixation - Fixation of atmospheric Nitrogen into Nitrogenous Salts with the help of Micro-organisms.
- 43. Two types of Biological Fixation • 1. Symbiotic - Fixation of free nitrogen by micro-organisms in soil living symbiotically inside the plant. • 2. Non – symbiotic - Fixation carried out by free living micro-organisms. - Aerobic, Anaerobic and blue green algae. (Bacteria)
- 44. • The Exploitation of legumes as host of Rhizobium for symbiotic nitrogen fixation has been dwindling due to the availability of synthetic fertilizers. In Addition to symbiotic nitrogen fixation, mycorhizzal fungi are also sources of microbrial fertilizers due to their ability to colonize the root system and supply it with phosphorous
- 45. • Many local and foreign companies recommend some microbial inoculants such as Bio-N, Xemas, Solex, and Bokashi. Among these microbial fertilizers, Bio- N is widely recommended and being promoted by the government for Rice, Corn, and Vegetables under the Tipid Abono Program and Organic Agriculture Program.
- 46. Crop Rotation •This is the growing of crops alternately in different parts of the farm in planned fashion to protect the soil from erosion and to build the fertility.