Sensor-based Nitrogen Application – Converting Research to Practicality Brent Rendel Rendel Farms Miami, Oklahoma

Response to Fertilizer N / Long-term Wheat Experiment, Lahoma, OK

“After the FACT” N Rate required for “MAX Yields” Ranged from 0 to 140 lbs N/ac Response to Fertilizer N / Long-term Wheat Experiment, Lahoma, OK

2004/2005 Wheat OSU placed 3-level nitrogen strips in 1 field (113.5 acres) Planting N: 30 lb/ac ZERO additional nitrogen called for by GreenSeeker in February All other fields on farm received 12 gal/ac of 28% UAN as topdress $185/ton) Farm avg yield: 33.0 bu/ac Test field yield: 33.9 bu/ac Total Savings: over $1700 on one field!

2005 Corn OSU placed Corn nitrogen test in one field using various nitrogen levels (Check - 0, FP - 110, GS – 75+sidedress, N-Rich - 300) as part of statewide research GS called for ZERO sidedress Nitrogen Farmer Practice and GreenSeeker tied for highest yield/acre (102 bu/ac) Highest profit/acre obtained was on check, closely followed by GreenSeeker Extra $13/ac profit from GreenSeeker!

2005/2006 Wheat Placed 3-level nitrogen strips in 38 fields Planting N: 25 lbs/ac Topdressed at GreenSeeker rate plus 10 lb/ac of N GreenSeeker prescriptions varied from 0 to 80 lbs/ac of additional N Farm avg yield: 24.4 bu/ac Reduced fertilizer expenses an average of $15/ac while obtaining yields similar to other farms in county = over $25,000 saved!

2006 Corn OSU placed nitrogen test in one field using various nitrogen levels (Check – 0, FP – 70, GS – 75+sidedress, GS – 0+sidedress, N-rich – 300) as part of continuing statewide research Both GS sidedress prescriptions were ~37 lbs N/ac N-rich returned the highest yield Check returned highest profit/acre followed by GS (0+36) and FP Lower Nitrogen use without lowering profits!

2006/2007 Wheat OSU placed nitrogen ramps in 7 fields 175 lb N/ac nitrogen strips in remaining 30+ fields Planting N: 25 lbs/ac Topdressed with 28% UAN at rate consistent with GreenSeeker prescription (0, 5, 7.5, 10 gal/ac) Farm avg yield: Don’t ask! Applied fewer Tons of UAN with GreenSeeker vs. 2#/ac of yield goal method saving $22.50/ac = over $39,000 saved!

Case Study 2003/4: Winter wheat with 50 lbs N/ac at planting followed with 40 lbs N/ac topdress; Yield – 32.4 bu/ac (1.7 bu above farm avg) 2004/5: Winter wheat with 30 lbs/ac at planting and ZERO topdress N (Yield – 33.9 bu/ac (0.9 bu above farm avg) followed by no-till soybeans; yield bu/ac (2.3 bu above farm avg) 2006: No-till soybeans harvested as forage hay; yield – 3.1 tons/ac (~10 lbs of N/acre removed with stover) Cropping history:

Case Study Surface soil test pulled Feb 2007: N – 171 lbs/ac, P – 42 lbs/ac, K – 73 lbs/ac for 150 bu/ac Silage corn planted 4/2 with 50 lbs N/ac pre-plant Applied two N ramps after planting Sensed N ramps 5/28 (V7+) with results varying between zero and 90 lbs/ac N required Applied 8.8 gal/ac of 32% UAN on 5/29 (31# N/ac) 32% UAN cost was ~$0.50/lb of N

Case Study Harvested 7/27 & 7/28 with a final yield of 21 tons/acre!

Lessons Learned Start slow Don’t adjust your farm to the technology…adjust the technology to your farm! Question EVERYTHING Don’t dig trenches just because the computer says it will solve the problem Believe your results Concentrate on Profit/acre vice Yield/acre Communication

Resources Website – Brent Rendel –6504 S 600 Rd, Miami, OK –