Presentation Outline. Soil Sampling. Automation and Precision. Soil Test

Transcription

1 Using Fertilizer and Soil Amendments by Prescription Improves Farming Practices Management Units Use field characteristics (soil type, size, history) websoilsurvey.nrcs.usda.gov Shelby Filley Regional Livestock & Forage Specialist Presentation Outline Soil Sampling Soil Testing and Reports Fertilizer Guidelines Plant nutrients (N-P-K-S ) and Fertilizer materials and lime Least-cost application Tracking nutrients and yield Collect subsamples randomly about the management unit. Combine into one composite sample to submit to certified lab. Soil Test Automation and Precision Accurate determination of soil status Efficient Fertilizer Program Economics Environment Optimizes forage growth Assess property value Cost of Improvements 2 million lb of soil in the top 6" of an acre 1

2 Sampling Depth Plow depth Soil Test Report: Other items Root zone 6" grass-clover 12" alfalfa Nitrogen (N) and Sulfur (S) Very mobile in soil & soil test results not used for fertilizer recommendations Pastures/hay ground OSU fertilizer guide (FG 63) lb/ac N (1 3 times per year) lb/ac S in the spring Variable-depth sampling Nitrogen application refined EM Evaluating Soil Nutrients and by Depth PNW614 Soil Test Report: Main items Sample Phosphorus P-ppm Potassium K-ppm Magnesium Mg-ppm Calcium Ca-ppm Buffer* Soil Weak Bray Olsen Index Soil Test Report: Other items Cation Exchange Capacity (CEC) Indicates potential to hold plant nutrients Capacity of soil to exchange cations (Ca, Mg, K, Na, H, Al) Highest in clay soils and high organic matter soils Base saturation Percentage of exchange sites occupied by basic cations (Ca, Mg, K, Na) If 100%, there is no exchangeable acidity (acidic cations H and Al). Neither used in OSU fertilizer recommendations Not very precise Lack evidence for agronomic response 2

3 Cation exchange in action Fertilizer and Lime Materials (FG 52) Compare Soil Test with Crop Needs Use OSU Fertilizer Guides (FG) and Pacific Northwest (PNW) bulletins Alfalfa (FG 18, FG 60, PNW 611) Grass & Legume Pastures and Hayground (FG 22, FG 63) Soil Test Interpretation Guide (EC 1478) Other crop fertilizer guides available FG 52 - Fertilizer and Lime Materials FG 76 - Irrigation Water Quality EM Early Spring Forage Production for W. OR Pastures PNW Pasture and Grazing Management in the Northwest Fertilizer Materials All values are on a percentage basis (%) Nitrogen N Phosphorus P 2 O 5 Potassium K 2 O N-P-K-S Sulfur S Name Triple Urea Ammonium Sulfate (AMS) Mono-Ammonium- Phosphate (MAP) Potash Ammonium-Phosphate- Sulfate Soil Test Report: Main items Sample Phosphorus P-ppm Potassium K-ppm Magnesium Mg-ppm Calcium Ca-ppm Buffer* Soil Weak Bray Olsen Index Quantities of Nutrients from selected fertilizer applications Example percentage in fertilizer X Amount product applied = pounds nutrient applied Fertilizer lb/a applied N P K S Triple Urea AMS FG 63 is okay, Ca and Mg are good P is low, add lb P 2 O 5 /ac K is good (>200) 0.16 X 200 = MAP Potash

4 Crop-specific Raising with lime for grass and clover Sub-clover and tall fescue relatively acid tolerant White clover and orchard grass less tolerant > 6.5 for alfalfa Ag Lime CaCO 3 Dolomite CaMgCO 3 Not all Ca products are good liming agents Gypsum or CaSO 4 does not change Rock dust? Nutrient availability vs. Soil Amendments Ag composts Wood ash Analyze as composts or ash (tell lab) Some increase (lower acidity in soil) Lime Application Rates (100-score lime) Lime score (rating) If SMP Buffer test for lime is : Apply this amount of lime (t/a): Under Over Calcium Carbonate Equivalents (cce) pure CaCO3 = 100 Fineness Factor (ff) Moisture factor (mf) Lime score =cce x ff x mf Price sources and adjust tonnage applied based on lime score 4

5 Cost Benefit Analysis $35 cost to test soil (mailing & Lab fee) of a 10 acre field Cost $120/T lime Guess 2 T/acre Soil test calls for 1 T/acre Difference is 1 T/acre X 10 acre X $120/T = $1200 savings in materials Calculating Lime Savings Example need of 60 lb N and 20 lb S per acre AMS = lb N/.21 = 286 lb AMS 286 lb AMS x.24 = 69 lb S 286 lb AMS/100 X 110 acidity index = 315 lb lime to neutralize acidity Cost 286 lb AMS x $482/T = 286 lb x $482/2000 lb = $ lb lime x $120/T = 315 lb x $120/2000 lb = $18.90 Total cost of $87.83 per acre in materials Application cost for 601 lb material Environmental cost of leached sulfur Cost Benefit Analysis (continued) Or add too little and suffer production loss If forage loss is 1 Ton/acre 1 T/ac x 10 acre = 10 T loss Hay $200/T x 10 T = $2,000 loss Lime not applied $120/T x 10 T = $1200 not spent Difference $2000 loss + $1200 not spent = $800 net loss Calculating Lime Savings Example need of 60 lb N and 20 lb S per acre Ureasul (½ AMS + ½ Urea; ) 60 lb N/.33 N = 182 lb Ureasul 182 lb Ureasul x.12 S = 22 lb S 182 lb Ureasul/100 x 91 acidity index = 166 lb lime to neutralize acidity Cost 182 lb Ureasul x $600/T = 182 lb x $600/2000 lb = $ lb lime x $120/T = 166 lb x $120/2000 lb = $9.96 Total cost of $64.56 per acre in materials Application costs of 342 lb of materials Acidifying Potential for Fertilizers Fertilizer Grade *Acidity Ammonium Sulfate Urea Ammonium Phosphate-sulfate /15 88 *Pounds of 100 score lime needed to neutralize the acidity produced by fertilizer application of 100 lb/ac Cost Comparison AMS vs. Ureasul Item AMS Ureasul Difference Materials cost ($/ac) $87.83 $64.56 $23.27 Materials applied (lb) 601 lb 348 lb 253 lb Environmental cost (lb S) 49 lb 0 lb 49 lb Time (hrs.) X hr. Y hr. $Z 5

6 Fertilizer Application to Pastures & Hay Ground FG 63 Forage Dry Matter, lb/a Seasonal Dry Matter Production RESULTS Early N application provides early-season forage /2 N /5 N Jan 15-Mar 4-May 23-Jun 12-Aug Date Traditional Control (0) Early N EM 8852, Early Spring Forage Production for Western Oregon Pastures EC 1478-E Soil Test Interpretation Guide Hay Removal Costs Nutrients Each ton of typical forage hay removes about 12 to 15 pounds of phosphate (P2O5) 50 to 60 pounds of potash (K2O) Also, need to provide about 30 to 50 pounds of nitrogen per acre on grassy stands (i.e. low legume component) Kopecky, et. al (2008) Fertilizer Application Fall Lime - sampling year Ag lime (CaCO 3 ) Dolomitic lime (+Mg) Other nutrients (yearly) Phosphorus (P) Potassium (K) Some Nitrogen (N) Spring Nitrogen Split applications (early & late) Sulfur Boron sampling year Between hay cuttings Nitrogen (urea) Other Sources of Nitrogen N2 fixation by legumes Amounts ( lb N/ac) Available to grasses as legumes die N from urine and feces Amounts vary w/ source Distribution varies w/ stock 6

7 Fertilizer and Money Agronomic response to inputs Improved production Spread over the cost of other inputs Time Equipment Fuel Use enterprise budget sheets to track forage production costs Animal Unit Month (AUM) = Forage Animal Unit (AU) 1000-pound cow +/- calf Animal Unit Month (AUM) = lb of forage required for one animal unit for one month 1000 lb cow eats ~ 2.5% body wt in feed/day 1000 lb x = 25 lb daily feed intake 25 lb/day x 30 days/month = 750 lb/mo Forage Yield Summary Measure yield (tons of hay and animal unit months carried) Compare your yield (t/ac) with comparable production situations soils interpretation sheets for potential websoilsurvey.nrcs.usda.gov Track yield over time with fertilizing according to soil test. Soil test and fertilize according to test Use fertilizer knowledge for least cost Know your potential yield Grow lots of high-quality plants! Hay Yield = No. bales x bale wt. / ac = 800 bales x 60 lb/bale / 10 acres = 4,800 lb/ac = 2.4 t/a 7