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Download Soil Fertility Management By Allah dad Khan Objectives Understand objectives of soil fertility management Understand objectives of soil fertility management

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  • Slide 1
  • Slide 2
  • Soil Fertility Management By Allah dad Khan
  • Slide 3
  • Objectives Understand objectives of soil fertility management Understand objectives of soil fertility management Philosophies/techniques of precision farming Philosophies/techniques of precision farming Using & obtaining valid soil samples Using & obtaining valid soil samples Considerations in making/following fertilizer recommendations Considerations in making/following fertilizer recommendations Knowledge of fertilizer quality Knowledge of fertilizer quality How to calculate fertilizer blends How to calculate fertilizer blends Fertilizer application methods Fertilizer application methods Benefits/limitations of manure use Benefits/limitations of manure use
  • Slide 4
  • Introduction Fertilizer is one management option used almost universally Fertilizer is one management option used almost universally Must replace soil nutrients lost by harvest Must replace soil nutrients lost by harvest Over-fertilization can result in dangerous pollution Over-fertilization can result in dangerous pollution Technology has increased fertilizer efficiency Technology has increased fertilizer efficiency
  • Slide 5
  • Goals & Concerns in Fertility Management Goals regarding fertility Goals regarding fertility Increase yield Reduce costs/unit production Improve product quality Avoid environmental pollution Improve environmental health & aesthetics
  • Slide 6
  • Goals & Concerns in Fertility Management Efficient land managers: spend 50% increase in yields Efficient land managers: spend 50% increase in yields Fertilizers may not be profitable if: Fertilizers may not be profitable if: Water is the most limiting factor Other growth hindrances insects, diseases, acidity, extreme cold Increased yield has less market value than the cost of buying/app of fertilizer
  • Slide 7
  • Goals & Concerns in Fertility Management Fertilizers generally most profitable farm input Fertilizers generally most profitable farm input Soil fertility problems usually the easiest to solve Soil fertility problems usually the easiest to solve Soil nutrients typically present in finite amounts, dont replenish themselves Soil nutrients typically present in finite amounts, dont replenish themselves Crops typically contain: (in rank of amount found in the plant) N, K, Ca, P, Mg, S Crops typically contain: (in rank of amount found in the plant) N, K, Ca, P, Mg, S
  • Slide 8
  • Goals & Concerns in Fertility Management Utilizing fertilizers may help cut unit cost of production by maximizing yield Utilizing fertilizers may help cut unit cost of production by maximizing yield Improved fertility = improved yields, improved aesthetic appeal Environmental concerns abound Environmental concerns abound Fertilizer laws viewed as lax by some Farmers may be the primary cause of non-point-source pollution
  • Slide 9
  • Goals & Concerns in Fertility Management Three common pollutants: Nitrates Nitrates Percolate through to groundwater Not safe to drink Cause Blue-baby syndrome inhibits oxygenation of blood Becoming common near heavily fertilized fields, feedlots, dairies Phosphates Phosphates Pollute surface waters by runoff Promotes algae growth in rivers/ponds Depletes available oxygen in the water for fish
  • Slide 10
  • Goals & Concerns in Fertility Management Wise use of fertilizers must be encouraged, actually improve the environment Crops, trees, etc. - remove more CO2, decrease sediment, dust, erosion Crops, trees, etc. - remove more CO2, decrease sediment, dust, erosion Plays important role for future of the planet Plays important role for future of the planet
  • Slide 11
  • Scale of Land Management Large- & Medium-Scale Management Large- & Medium-Scale Management Large-Scale Low levels of operational precision, little reliance on sophisticated technology Low levels of operational precision, little reliance on sophisticated technology May be most feasible/profitable for some May be most feasible/profitable for some Simple & low-tech Simple & low-tech Some shy away from high tech for other reasons Some shy away from high tech for other reasons
  • Slide 12
  • Scale of Land Management Disadvantages Disadvantages Some parts of field may receive too much/little fertilizer or pesticide Less than optimal yields Inefficient use of fertilizers & pesticides Higher cost of production/unit Environmental pollution due to over application Advantages Advantages Minimal technological training & instrumentation needed Field operations can be performed w/ standard, readily available, cheaper equipment
  • Slide 13
  • Scale of Land Management Medium-Scale Subdivide field into two+ management units Subdivide field into two+ management units Delineation may be based on: Soil types Soil types Past management differences Past management differences Farmers observations Farmers observations Ex. High, medium, low N application areas in the field Ex. High, medium, low N application areas in the field Same equipment/technology needs as for large-scale management farmers Same equipment/technology needs as for large-scale management farmers
  • Slide 14
  • Scale of Land Management Does improve efficiency of farm inputs Does improve efficiency of farm inputs Can reduce excessive applications of chemicals/fertilizers Can reduce excessive applications of chemicals/fertilizers May do spot treatments/applications w/in a field due to field observations Small-Scale Management (Precision Farming) Small-Scale Management (Precision Farming) Global Positioning System (GPS) network of U.S. satellites w/ a signal detection system used to locate positions on the ground
  • Slide 15
  • Scale of Land Management Soil sample fields on a grid Data collection points no more than a few feet apart Each sample site mapped using GPS Custom applicators can custom apply fertilizers at variable rates that change constantly as the applicator travels the field variable rate application, site- specific management, precision farming
  • Slide 16
  • Scale of Land Management Potential to substantially decrease fertilizer/chemical application rates Potential to substantially decrease input costs Does require expensive technology, equipment & extensive technical knowledge
  • Slide 17
  • Soil Tests Law of the Minimum: growth of the plant is limited most by the essential plant nutrient present in the least relative amount (first-limiting) Soil Acidity Evaluation Soil Acidity Evaluation pH measured w/ electrode & solution Lime requirement amount of lime required to achieve desired pH Reported as buffer pH Reported as buffer pH
  • Slide 18
  • Soil Tests Soil Test for N Soil Test for N No good tests for soil available N Most states provide N recommendations based on yrs of field plots trials on various crops, soils, management, fertilizers N recommendations consider: Previous crops Previous crops Estimates N carryover Estimates N carryover N needed to decompose residues N needed to decompose residues Projected yields Projected yields Climate Climate
  • Slide 19
  • Soil Tests Lab N tests accurate, but nearly impossible to interpret Some will discourage N testing Some will discourage N testing Behavior of carryover N unpredictable can make analyses invalid Leaching Leaching Denitrification Denitrification Mineralization Mineralization Climate Climate
  • Slide 20
  • Soil Tests N recommendations based on yield goals rather than soil reserves Corn Rule 1.2-1.4#N/bu of yield goal How much N should be recommended for corn following corn, expected yield 120 bu/ac? How much N should be recommended for corn following corn, expected yield 120 bu/ac? How much N should be recommended for corn following soybeans, expected yield 195 bu/ac? How much N should be recommended for corn following soybeans, expected yield 195 bu/ac?
  • Slide 21
  • Soil Tests Soil Tests for P & K Soil Tests for P & K Widely used to predict probability of crop response to fertilization Survey: 47% soil tested medium to low for P 47% soil tested medium to low for P 43% soil tested medium to low for K 43% soil tested medium to low for K P & K soil levels declining in many states P & K soil levels declining in many states P testing Quite reliable soil P is very stable from yr to yr Quite reliable soil P is very stable from yr to yr
  • Slide 22
  • Soil Tests Most soil P unavailable to crops Most soil P unavailable to crops Soil test extracts & measures what may actually be available Soil test extracts & measures what may actually be available K testing Tests both exchangeable & soluble reserves Tests both exchangeable & soluble reserves Conflicting testing procedures over which is most accurate Conflicting testing procedures over which is most accurate Some estimate upper threshold needs ~159- 246#/ac (above which no response to K fertilizer) Others - 335#/ac on clay soils (calculated based on soil CEC higher CEC = decreased available K) Some experimentation w/ soil probes checking K, NO 3, PO 4, SO 4
  • Slide 23
  • Soil Tests Soil Test for Ca & Mg Soil Test for Ca & Mg Related to need for lime Well-limed soils rarely Ca & Mg deficient Mg deficiency more common than Ca Coarse-textured or acidic soils Coarse-textured or acidic soils Many yrs

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