Seed Health Management for Better Productivity - Govind Ballabh ...

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(Seed Health Management for Better Productivity)5) Cropping system6) IrrigationComponents of soil health/ quality managementThe seven components of soil quality management are discussed briefly below: Choosingspecific practices within each component depends on the situation since different types of soilrespond differently to the same practice. Each combination of soil type and land use calls for adifferent set of practices to enhance soil quality.1. Enhance organic matter content: Whether the soil is naturally high or low in organic matter,adding new organic matter in the form of compost, crop residues etc every year is perhaps themost important way to improve and maintain soil quality. Regular additions of organic matterimprove soil structure, enhance water and nutrient holding capacity, protect soil from erosionand compaction, and support a healthy community of soil organisms. Practices that increaseorganic matter include: leaving crop residues in the field, choosing crop rotations that includehigh residue plants, using optimal nutrient and water management practices to grow healthyplants with large amounts of roots and residue, growing cover crops, applying manure orcompost, using low or no tillage systems, and mulching.2. Avoid excessive tillage: Tillage is used to loosen surface soil, prepare the seedbed, andcontrol weeds and pests. But tillage can also break up soil structure, speed up thedecomposition and loss of organic matter, increase the threat of erosion, destroy the habitat ofhelpful organisms, and cause compaction. New equipment allows crop production with minimaldisturbance of the soil.3. Manage pests and nutrients efficiently: An important function of soil is to buffer and detoxifychemicals, but soil's capacity for detoxification is limited. Pesticides and chemical fertilizershave valuable benefits, but they also can harm non-target organisms and pollute water and airif they are mismanaged. Nutrients from organic sources also can pollute when misapplied orover-applied. Efficient pest and nutrient management means testing and monitoring soil andpests; applying only the necessary chemicals, at the right time and place to get the job done;and taking advantage of non-chemical approaches to pest and nutrient management such ascrop rotations, cover crops, and manure management.4. Prevent soil compaction: Compaction reduces the amount of air, water, and space availableto roots and soil organisms. Compaction is caused by repeated traffic, heavy traffic, ortraveling on wet soil (such as puddling for rice transplanting). Deep compaction by heavyequipment is difficult or impossible to remedy, so prevention is essential.5. Keep the ground covered: Bare soil is susceptible to wind and water erosion, and to dryingand crusting. Ground cover protects soil, provides habitats for larger soil organisms, such asinsects and earthworms, and can improve water availability. Ground can be covered by leavingcrop residue on the surface or by planting cover crops. In addition to ground cover, living covercrops provide additional organic matter, and continuous cover and food for soil organisms.Ground cover must be managed to prevent problems with delayed soil warming in spring,diseases, and excessive build-up of phosphorus at the surface.- 64 -
(Seed Health Management for Better Productivity)6. Diversify cropping systems: Diversity is beneficial for several reasons. Each plant contributesa unique root structure and type of residue to the soil. A diversity of soil organisms can helpcontrol pest populations, and a diversity of cultural practices can reduce weed and diseasepressures. Diversity across the landscape can be increased by using buffer strips, small fields,or contour strip cropping. Diversity over time can be increased by using long crop rotations.7. Manage irrigation: Use of excessive amounts of water for irrigation is not only wasteful butalso harmful. Excess water may cause water logging if proper drainage system is not in place.Excessive withdrawal of ground water for irrigation lowers the ground water level. If theirrigation water quality is brackish, soil salinity builds up which lowers the soil productivity.Soil factors that influence seed qualityS.No.Soil factorsSeed quality parameters that are affected1 Acidity, alkalinity, Grain size, bldness, uniformity, viability, disease incidence2 Salinity Grain size, boldness, uniformity, viability3 Nutrient supply Grain size, boldness, uniformity, viability, disease incidence4 Organic matter Grain size, boldness, uniformity, viability, disease incidence5 Soil aggregation Grain size, uniformity6 Moisture availability Grain size, boldness, uniformity, viability7 Aeration (water logging) Grain size, boldness, uniformity, viability8 Compaction Grain size, boldness, uniformity, viability9 Soil microbes Disease incidence, viability, uniformity10 Bioinoculation (N 2 fixers, Grain size, viability, uniformity, disease incidenceBiocontrolmicroorganisms)Disease Suppressive SoilsPlant diseases are caused mainly by fungi, bacteria, viruses and nematodes. Soil biotacontain a number of these pathogens, beside a large number of beneficial organisms. Thephenomenon of disease suppressive soils has fascinated plant pathologists for decades.Suppressive soils are those in which a specific pathogen does not persist despite favorableenvironmental conditions or the pathogen establishes but doesn't cause disease, or diseaseoccurs but diminishes with continuous monoculture of the same crop species. The phenomenon isbelieved to be biological in nature because fumigation or heat-sterilization of the soil eliminates thesuppressive effect, and disease is severe if the pathogen is re-introduced.Potato scab, a soil-borne disease, is much more severe in alkaline soils. It can beprevented by the use of fertilizers and soil treatments that bring pH so low that the scab organismcannot grow. The reverse is true of wilt and club root diseases of cabbage, which is made worseby acid soil; the use of alkaline materials helps control these diseases.REFERENCES1. Doran, J.W., Sarrantonio, M and Liebig, M.A. (1996) Soil Health and Sustainability. Advances inAgronomy 56, 1-54.2. Sharma, K.L., Mandal, U.K., Srinivas, K., Vittal, K.P.R., Mandal, B., Grace, J.K. and Ramesh, V.(2005) Long-term soil managmenet effects on crop yields and soil quality in a drylandAlfisol. Soil & Tillage Research 83, 246-259.- 65 -
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potential. An improvement in qualit
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9. Session Arrangement CommitteeDr.
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9. Dr. Pradip Kumar BorahSr. Scient
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TRAININGONANNEXURE-IIISEED HEALTH M
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ANNEXURE-IVCENTRE OF ADVANCED STUDI
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SundayApril 6MondayApril 7TuesdayAp
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TuesdayApril 15WednesdayApril 16Thu
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