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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  • Slide 1
  • Unit 9: Soil Fertility Management Chapter 10
  • Slide 2
  • 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 3
  • 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 4
  • 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 5
  • 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 6
  • 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 7
  • 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 8
  • 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 9
  • 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 10
  • 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 11
  • 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 12
  • 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 13
  • 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 14
  • 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 15
  • 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 16
  • Soil Sampling Standard method for determining soil fertility Use w/ precision farming to minimize inputs Accuracy of sample is key!!!!
  • Slide 17
  • Soil Sampling Depth & Number of Samples Depth & 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
  • Slide 18
  • Soil Sampling Sampling Frequency, Time, & Location Sampling Frequency, Time, & 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 & which will need to be supplied Samples often pulled in fall to provide enough time for analysis/amendments
  • Slide 19
  • 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
  • Slide 20
  • 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
  • Slide 21
  • Soil Sampling Sampling area Each composite sample should represent
  • Soil Tests Soil Test for S & B Soil Test for S & 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
  • Slide 32
  • 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
  • Slide 33
  • 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
  • Slide 34
  • 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
  • Slide 35
  • 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
  • Slide 36
  • Analysis of Plants Chop/mix, squeeze sap & test Chop/mix, squeeze sap & 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
  • Slide 37
  • Analysis of Plants Indicate part of plant sampled & be consistent Dry to prevent spoilage (confounds results) Wrap in paper and mail w/ complete report complete history, information critical
  • Slide 38
  • 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
  • Slide 39
  • 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
  • Slide 40
  • 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
  • Slide 41
  • 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
  • Slide 42
  • 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
  • Slide 43
  • 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
  • Slide 44
  • Fertilizer Recommendations Developing a Fertilizer Recommendation Developing a Fertilizer Recommendation Must have sufficient plot data to correlate yields & 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
  • Slide 45
  • 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
  • Slide 46
  • 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
  • Slide 47
  • 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 & Basicity of Fertilizers Acidity & 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
  • Slide 48
  • Fertilizer Quality Solubility & Mobility in Soil Solubility & Mobility in Soil Function of: Elemental charge Elemental charge Tendency to form insoluble compounds Tendency to form insoluble compounds Adsorption ability Adsorption ability Soil texture Soil texture Water movement Water movement Concentration of other ions Concentration of other ions
  • Slide 49
  • Fertilizer Quality Examples P may only move a few cm P may only move a few cm Must be place in/near root zone N can move w/ extent of water movement N can move w/ extent of water movement
  • Slide 50
  • Fertilizer Calculations Calculating Fertilizer Mixtures Calculating Fertilizer Mixtures Mixing 34-0-0 ammonium nitrate & 0-46- 0 TSP to get 1 ton mixture of 15-10-0 How much of each do we need? How much of each do we need? How about if we needed a 12-14-6 fertilizer for a customer? What might we use for each ingredient? What might we use for each ingredient? How much of each would we need? How much of each would we need?
  • Slide 51
  • Fertilizer Calculations Weights of Fertilizer to Apply Weights of Fertilizer to Apply Planting corn expected to yield 125 bu/ac How much N do we need? How much N do we need? Soil analysis recommended 88#/ac phosphate Soil analysis recommended 88#/ac phosphate How much ammonium nitrate & TSP do we need? How much ammonium nitrate & TSP do we need? What is our final application rate? What is our final application rate?
  • Slide 52
  • Fertilizer Calculations Calculations Involving Liquid Fertilizers Calculations Involving Liquid Fertilizers Use dry fertilizer calculation if sold by weight If sold by volume, usually applied by volume See example pg. 336
  • Slide 53
  • Techniques of Fertilizer Application Starter (Pop-Up) Fertilizers Starter (Pop-Up) Fertilizers Addition of fertilizer w/ the seed during planting, dribbled in a strip near the see, banding w/in 2 of seed Most beneficial for P, K some for N, but not as necessary Advantages: Cold soils Cold soils Low nutrient levels in the root zone Low nutrient levels in the root zone Fast-growing plants Fast-growing plants
  • Slide 54
  • Techniques of Fertilizer Application Disadvantages: Slows planting Slows planting Can burn seedling, if placed too close Can burn seedling, if placed too close Broadcast Application Broadcast Application Uniform application across entire surface Left on surface, or incorporated Somewhat less efficiency of fertilizer Especially when not incorporated quickly Especially when not incorporated quickly Why? Why?
  • Slide 55
  • Techniques of Fertilizer Application Reasons to broadcast: Only practical method of application pastures, turf, etc. Only practical method of application pastures, turf, etc. Low-fertility soils needing high fertilizer rates Low-fertility soils needing high fertilizer rates Easy, cheap, personal preference Easy, cheap, personal preference Flexible split applications, ability to add after crop is growing Flexible split applications, ability to add after crop is growing
  • Slide 56
  • Techniques of Fertilizer Application Deep Banding Deep Banding Application of strips into the soil Either between/side of row, where the seed may be planted Typically 4-12 depth Knifing in anhydrous most common Gas able to dissolve in soil water before it escapes Gas able to dissolve in soil water before it escapes Losses can be high if dry, sandy Losses can be high if dry, sandy
  • Slide 57
  • Techniques of Fertilizer Application Disadvantages: Strong equipment needed Strong equipment needed High fuel costs High fuel costs Danger of dealing w/ anhydrous Danger of dealing w/ anhydrous Advantages: High yield response potential High yield response potential Puts fertilizer where most roots are, very efficient use Puts fertilizer where most roots are, very efficient use
  • Slide 58
  • Techniques of Fertilizer Application Split Application Split Application Divided total fertilizer rates delivered in 2+ applications Reasons to split applications If large applications are needed increase efficiency of nutrient use If large applications are needed increase efficiency of nutrient use Soil conditions dictate risk for high nutrient losses Soil conditions dictate risk for high nutrient losses Control vegetative growth in early stages Control vegetative growth in early stages
  • Slide 59
  • Techniques of Fertilizer Application Advantages: Increased efficiency of N utilization Increased efficiency of N utilization Provide a boost to the plant during growth Provide a boost to the plant during growth Disadvantages: Extra pass through field Extra pass through field Not effective for P, K because of immobility Not effective for P, K because of immobility
  • Slide 60
  • Techniques of Fertilizer Application Side-Dressing or Topdressing Side-Dressing or Topdressing Side-dressing surface or shallow band application put on after crop is growing Broadcast, surface stripped, sprayed, knifed Broadcast, surface stripped, sprayed, knifed Principles to consider: Decreases potential N losses Decreases potential N losses Added in the furrow to allow water to help w/ infiltration Added in the furrow to allow water to help w/ infiltration Not effective for P, K Not effective for P, K
  • Slide 61
  • Techniques of Fertilizer Application Point Injector Application place P, K into soil in the root zone w/out significant root damage Point Injector Application place P, K into soil in the root zone w/out significant root damage Used more in small plots, gardens Push stick, rod into soil, fill w/ fertilizer, cover Effective for: fruit trees, grapes, shrubs, etc. Not common in field use
  • Slide 62
  • Techniques of Fertilizer Application Fertigation application of fertilizer w/ irrigation water Fertigation application of fertilizer w/ irrigation water Can apply large quantities of nutrients Very effective for N Some see 30-50% more efficient use of N Some see 30-50% more efficient use of N Cut of 50% in N rates w/ same/better yield Cut of 50% in N rates w/ same/better yield Must be careful of potential problem w/ salts
  • Slide 63
  • Techniques of Fertilizer Application Able to apply when need is highest Immediate/convenient application Most effective on soils w/ poor nutrient retention & for mobile nutrients Chemigation also possible not discussed in depth here
  • Slide 64
  • Techniques of Fertilizer Application Foliar Application foliage wetted to maximize nutrient absorption through leaf stomata & epidermis Foliar Application foliage wetted to maximize nutrient absorption through leaf stomata & epidermis Feasible for: N supplementation, pesticides, micronutrients, etc. Guidelines: Only suited for applications of small amount (can burn plant) Only suited for applications of small amount (can burn plant) Decreased rates can be used Decreased rates can be used
  • Slide 65
  • Techniques of Fertilizer Application Need wetting agent to help the spray to distribute evenly across surface Need wetting agent to help the spray to distribute evenly across surface Helpful when root conditions restrict nutrient uptake Helpful when root conditions restrict nutrient uptake Quick response/remedy to deficiency (also short residual) Quick response/remedy to deficiency (also short residual) Wind must be calm, humidity >70%, temp 70%, temp
  • Fertilizer Efficiency Plant Root Systems Plant Root Systems Some plants better scavengers than others Absorption greatly affected by fertilizer distribution Smaller root system = shorter growing season = >dependence on fertilizer Growth rates & size also effect amount of nutrients demanded
  • Slide 70
  • Fertilizer Efficiency Weeds Weeds Response to fertilizer much like crops N fertilization may increase weed growth > crop growth Application method can also affect weed growth Ex broadcast fertilizer can tend to help weeds get good start Ex broadcast fertilizer can tend to help weeds get good start
  • Slide 71
  • Fertilizer Efficiency Fertilizer-Water Interactions Fertilizer-Water Interactions Availability of nutrients directed impacted by soil water content Drip fertigation may be most efficient use of water & fertilizer Common in greenhouses Common in greenhouses Can be effective in field use Can be effective in field use Israeli farming uses drip irrigation
  • Slide 72
  • Fertilizer Efficiency Fertilizing for High Efficiency Fertilizing for High Efficiency Guides to optimal fertilization: Avoid large additions of N or K (50#/ac +) on sandy soils use split application Avoid large additions of N or K (50#/ac +) on sandy soils use split application Avoid broadcast applications of urea & ammonia on warm/moist soils volatilizes easily incorporate Avoid broadcast applications of urea & ammonia on warm/moist soils volatilizes easily incorporate Avoid N losses on poorly drained soils by using ammonium Avoid N losses on poorly drained soils by using ammonium Band P Band P Use starter fertilizer Use starter fertilizer
  • Slide 73
  • Fertilizer Efficiency Keep N & K fertilizers out of seedling zone to avoid burn Keep N & K fertilizers out of seedling zone to avoid burn Reduce leaching by avoiding application before rain or irrigation Reduce leaching by avoiding application before rain or irrigation Foliar apply, if feasible/appropriate Foliar apply, if feasible/appropriate Know nutrient demands of crop Know nutrient demands of crop Improve management Improve management Remember law of minimum Remember law of minimum Soil test Soil test
  • Slide 74
  • Livestock Manure as Fertilizer Many benefits of using manure: Recycles nutrients Recycles nutrients Potential to reduce pollution Potential to reduce pollution Adds C to soil Adds C to soil Improve aggregation, infiltration, microbial vigor Improve aggregation, infiltration, microbial vigorRisks: Increased weed pressure Increased weed pressure High cost of obtaining/applying if you dont own it High cost of obtaining/applying if you dont own it
  • Slide 75
  • Livestock Manure as Fertilizer Not as convenient as commercial fertilizer Not as convenient as commercial fertilizer Pollution anxiety Pollution anxiety Nutrient Production & Recovery Nutrient Production & Recovery Production rates predictable & measurable Ration has heavy influence on nutrients in manure
  • Slide 76
  • Livestock Manure as Fertilizer Manure & Nutrient Budgets Manure & Nutrient Budgets Generous applications of manure no longer norm Some states require & enforce strict manure management guidelines Some states require & enforce strict manure management guidelines Restricted application due to soil P levels instead of N Manure still cant meet plant needs alone Crops remove much higher levels of nutrients/ac Crops remove much higher levels of nutrients/ac
  • Slide 77
  • Livestock Manure as Fertilizer Using Manure Using Manure Most recognize advantages of using manure Manure production unevenly distributed in farmland Expensive to transport very far Too abundant in areas, not enough land for application
  • Slide 78
  • Livestock Manure as Fertilizer Must balance three factors Supply crop nutrients Supply crop nutrients Dispose of waste Dispose of waste Protect environment Protect environment More focus on manure later
  • Slide 79
  • Assignment

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