Unit 9: Soil Fertility Management Chapter 10. Objectives Understand objectives of soil fertility management Understand objectives of soil fertility management

Download Unit 9: Soil Fertility Management Chapter 10. Objectives Understand objectives of soil fertility management Understand objectives of soil fertility management

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<ul><li> Slide 1 </li> <li> Unit 9: Soil Fertility Management Chapter 10 </li> <li> Slide 2 </li> <li> Objectives Understand objectives of soil fertility management Understand objectives of soil fertility management Philosophies/techniques of precision farming Philosophies/techniques of precision farming Using &amp; obtaining valid soil samples Using &amp; 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 </li> <li> Slide 3 </li> <li> 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 </li> <li> Slide 4 </li> <li> Goals &amp; 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 &amp; aesthetics </li> <li> Slide 5 </li> <li> Goals &amp; 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 </li> <li> Slide 6 </li> <li> Goals &amp; 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 </li> <li> Slide 7 </li> <li> Goals &amp; 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 </li> <li> Slide 8 </li> <li> Goals &amp; 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 </li> <li> Slide 9 </li> <li> Goals &amp; 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 </li> <li> Slide 10 </li> <li> Scale of Land Management Large- &amp; Medium-Scale Management Large- &amp; 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 &amp; low-tech Simple &amp; low-tech Some shy away from high tech for other reasons Some shy away from high tech for other reasons </li> <li> Slide 11 </li> <li> 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 &amp; pesticides Higher cost of production/unit Environmental pollution due to over application Advantages Advantages Minimal technological training &amp; instrumentation needed Field operations can be performed w/ standard, readily available, cheaper equipment </li> <li> Slide 12 </li> <li> 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 </li> <li> Slide 13 </li> <li> 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 </li> <li> Slide 14 </li> <li> 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 </li> <li> Slide 15 </li> <li> Scale of Land Management Potential to substantially decrease fertilizer/chemical application rates Potential to substantially decrease input costs Does require expensive technology, equipment &amp; extensive technical knowledge </li> <li> Slide 16 </li> <li> Soil Sampling Standard method for determining soil fertility Use w/ precision farming to minimize inputs Accuracy of sample is key!!!! </li> <li> Slide 17 </li> <li> Soil Sampling Depth &amp; Number of Samples Depth &amp; Number of Samples Sampling depth 7-12 for typical soil analysis Shallower depth for no-till/sod crops acid- layer can form at very top of soil structure Shallower depth for no-till/sod crops acid- layer can form at very top of soil structure For accurate N analysis 24-36 depth For accurate N analysis 24-36 depth For composite sampling fewer # samples decreases accuracy of analysis </li> <li> Slide 18 </li> <li> Soil Sampling Sampling Frequency, Time, &amp; Location Sampling Frequency, Time, &amp; Location New land, land new to you yearly for 1 st few yrs until you understand the soil Every 2-3 yrs, unless concern for environmental problems Analysis determines which nutrients can be made available in the soil &amp; which will need to be supplied Samples often pulled in fall to provide enough time for analysis/amendments </li> <li> Slide 19 </li> <li> Soil Sampling Spring sampling is more accurate, but conditions may not be favorable, or not sufficient time Spring sampling is more accurate, but conditions may not be favorable, or not sufficient time Sampling row crops problematic Can hit a fertilizer zone Can hit a fertilizer zone Hard to get enough representative samples Hard to get enough representative samples </li> <li> Slide 20 </li> <li> Soil Sampling Uniformity of Sampling Areas Uniformity of Sampling Areas Examine field for differences in soil characteristics, past treatments Consider: Uniformity of productivity Uniformity of productivity Topography Topography Soil texture Soil texture Soil structure Soil structure Drainage Drainage Depth/color topsoil Depth/color topsoil Past management Past management </li> <li> Slide 21 </li> <li> Soil Sampling Sampling area Each composite sample should represent </li> <li> Soil Tests Soil Test for S &amp; B Soil Test for S &amp; B S testing inaccurate acts much like N Can test but must take variability into account Can test but must take variability into account Boron level recommendations 5.0 ppm excess/toxicity risks </li> <li> Slide 32 </li> <li> Soil Tests Soil Test for Micronutrient Needs Soil Test for Micronutrient Needs Difficult to develop accurate tests due to relatively infrequent need for field supplementation Can be done, if requested for a specific need Adds expense to soil analysis </li> <li> Slide 33 </li> <li> Soil Tests How Good Is Soil Testing? How Good Is Soil Testing? Analyses recalibrated regularly based on field trial studies Validity of analysis related directly to accuracy of sample, information provided to the lab Soil analyses generally very valid for: P, K, soluble salts, pH, lime Other tests should only be used on as-needed basis Other tests should only be used on as-needed basis Extra cost Less accurate </li> <li> Slide 34 </li> <li> Analysis of Plants Only way to be sure of soil nutrient availability Plant Analysis vs. Soil Testing Plant Analysis vs. Soil Testing Plant most accurate report on what nutrients are actually available Plant analysis leaves little to no room for amendments to the soil When deficiencies are acknowledged, yield usually already affected </li> <li> Slide 35 </li> <li> Analysis of Plants When is plant analysis most helpful? Treatment of an easily-corrected deficiency Treatment of an easily-corrected deficiency Long-growing crops: turf, tree fruits, forests, sugar cane Long-growing crops: turf, tree fruits, forests, sugar cane Quick Tests in the Field Quick Tests in the Field Can test for N, K status in plants Collect ~20 leaves for sample Collect ~20 leaves for sample Must be random from different locations Dont select only affected-looking leaves </li> <li> Slide 36 </li> <li> Analysis of Plants Chop/mix, squeeze sap &amp; test Chop/mix, squeeze sap &amp; test Most effective for greenhouse/nursery growers Most effective for greenhouse/nursery growers Amendments can easily be made High possible economic losses Total Plant Analysis Total Plant Analysis Done in a lab Should be tested by stage of development Random sampling key </li> <li> Slide 37 </li> <li> Analysis of Plants Indicate part of plant sampled &amp; be consistent Dry to prevent spoilage (confounds results) Wrap in paper and mail w/ complete report complete history, information critical </li> <li> Slide 38 </li> <li> Analysis of Plants Interpreting Plant Analyses Interpreting Plant Analyses Accurate interpretation difficult if not all critical information provided Element classified as deficient if below threshold nutrient levels Levels change through season, stage of development, etc. Levels change through season, stage of development, etc. Some general disagreement from scientists on what threshold levels are </li> <li> Slide 39 </li> <li> Analysis of Plants Critical Nutrient Range Critical Nutrient Range CNR ranges at which nutrients are: Visually deficient Visually deficient Hidden deficient Hidden deficient Slightly deficient Slightly deficient Sufficient supply Sufficient supply Toxic Toxic </li> <li> Slide 40 </li> <li> Analysis of Plants Visual Nutrient Deficiency Symptoms Visual Nutrient Deficiency Symptoms Chlorosis yellowish to whitish appearance to foliage, stem Necrosis dead tissue Causes: disease, insect damage, salt accumulation, stress, nutrient deficiencies Some visual symptoms same for many diseases/deficiencies </li> <li> Slide 41 </li> <li> Analysis of Plants Nutrients are relocated in the plant by two pathways Xylem water-carrying vessels Xylem water-carrying vessels All nutrients can pass through Phloem sugar-carrying vessels Phloem sugar-carrying vessels Not all nutrients can relocate Mobile nutrients travel freely Immobile nutrients cant be moved from their location in the plant Mobile nutrient deficiencies tend to occur on older leaves plant sacrifices old for new tissue </li> <li> Slide 42 </li> <li> Analysis of Plants Immobile nutrient deficiencies symptoms on shoot/root tips, fruits Cant be treated from the soil w/ fertilizer plant cant send Ca (ex) to the ripening fruit Cant be treated from the soil w/ fertilizer plant cant send Ca (ex) to the ripening fruit Mobile nutrients: N, P, K, Cl, Mg, S N, P, K, Cl, Mg, S Immobile nutrients: Cu, Mn, Zn, Fe, Mo, S Cu, Mn, Zn, Fe, Mo, S Very immobile nutrients: B, Ca B, Ca </li> <li> Slide 43 </li> <li> Fertilizer Recommendations Different labs make different recommendations Traditional philosophies being challenged P application rates P application rates Yield-based N recommendations Yield-based N recommendations </li> <li> Slide 44 </li> <li> Fertilizer Recommendations Developing a Fertilizer Recommendation Developing a Fertilizer Recommendation Must have sufficient plot data to correlate yields &amp; nutrient needs Once a general amount of fertilizer is known: Subtract for manure application Subtract for manure application Subtract for residual P or N Subtract for residual P or N Add/subtract for N, P, S because of soil organic matter levels can count on them supplying some Add/subtract for N, P, S because of soil organic matter levels can count on them supplying some </li> <li> Slide 45 </li> <li> Fertilizer Recommendations Test Reports Test Reports Labs usually full-service Soil, plant, manure, irrigation water testing Soil, plant, manure, irrigation water testing See soil test report </li> <li> Slide 46 </li> <li> Fertilizer Quality Fertilizer grade amounts of N, P, K in a fertilizer required by law to be listed Also required: Also required: Weight of material, manufacturer Optional: Optional: Filler composition, acidity in soil potential Calculating fertilizer N, P, K amounts 10-20-10 10-20-10 15-12-18 15-12-18 </li> <li> Slide 47 </li> <li> Fertilizer Quality Amounts listed as: elemental N, phosphate, potash (not direct indication of elemental P, K supplied) Amounts listed as: elemental N, phosphate, potash (not direct indication of elemental P, K supplied) Acidity &amp; Basicity of Fertilizers Acidity &amp; Basicity of Fertilizers Most affect soil acidity in some regard Superphosphate, Triplesuperphosphate, Potash neutral Superphosphate, Triplesuperphosphate, Potash neutral MAP, DAP, all N fertilizers acidifiers MAP, DAP, all N fertilizers acidifiers </li> <li> Slide 48 </li> <li> Fertilizer Quality Solubility &amp; Mobility in Soil Solubility &amp; Mobility in Soil Function of: Elemental charge Elemental charge Tendency to form insoluble compounds T...</li></ul>