To determine if the timing of spring nitrogen application to wheat influences wheat yield in a modified relay intercropping system.
| Cooperator: | David Brewer |
| County of Site: | Crawford |
| Nearest Town: | Bucyrus |
| Major Soil Type: | Blount and Condit Bennington |
| Drainage: | Improved |
| Irrigation: | None |
| Tillage: | No-till |
| Previous Crop: | Soybeans |
| Soil Test: | pH 7.2 P 126 lbs/ac K 316 lbs/ac |
| Fall Fertilizer: | 300 lbs/ac 7-28-28 applied before planting |
| Herbicides: | Treatment 1: 0.5 pt 2,4-D applied 4/14/97 Treatment 2: 1 pt 2,4-D applied 4/19/97 |
| Varieties: | Patterson wheat, Resnick soybeans |
| Planting Dates: | 10/4/96 wheat, 6/20/97 soybean |
| Planting Rates: | 120 lbs/ac wheat, 90 lbs/ac soybean |
| Harvest Dates: | 7/21/97 wheat |
Top-dress nitrogen was applied to wheat at two different times. Treatment 1 was a single application of 65 lbs. of 28% N applied on 3/24/97, and Treatment 2 was a split application of 65 lbs. 28% N on 3/24/97 plus 60 lbs. of 28% N applied 4/16/97. Individual plot size was 0.35 acre with four replications of each treatment.
| 1997 Modified Relay Intercropping Wheat Nitrogen Evaluation | |||||
|---|---|---|---|---|---|
| Treatment | Rep 1 | Rep 2 | Rep 3 | Rep 4 | Average |
| Single N | 69.3 | 58.7 | 60.7 | 62.0 | 62.7 |
| Split N 76.3 | 78.0 | 77.7 | 73.0 | 76.3 | |
| F value 27.72, significant at .05 level, LSD 6.31 bu/a, CV = 5.25; design completely randomized | |||||
| Modified Relay Intercropping Wheat Yield Results (3-year average) | ||
|---|---|---|
| Year | Single N Application | Split N Application |
| 1994 | 61.5 | 68.2 |
| 1995 | 71.5 | 73.0 |
| 1997 | 62.7 | 76.3 |
| Three-Year Average | 65.2 | 72.5 |
|
No significant difference between three-year averages of nitrogen
treatments. 1996 year not analyzed due to severe wheat winter kill. Overall average of all treatments = 68.9 bu/ac. | ||
Wheat yield in split-applied nitrogen plots has not been significantly different from wheat yield where only a single rate of nitrogen has been applied. However, seven bushels of wheat (average difference over three years) would easily cover the costs of a split-nitrogen application and leave $10 or more per acre as added profit in recent growing seasons. This must be balanced with the always lower soybean yield following wheat with a split nitrogen application. The research in 1998 shall be redesigned to reflect a smaller nitrogen split-nitrogen rate in an attempt to maximize wheat and soybean yield. Finally, when looking at gross revenue generated, the MRI system has been very favorable where compared to single crops of either 80-bushel wheat or 55-bushel soybeans. Using $3.50 wheat and $6.50 soybeans, the three-year average of the MRI system averaged $445 gross revenue per acre. Eighty-bushel wheat would generate $280 per acre (no straw sales), and 55-bushel soybeans would calculate to $358 per acre.
Submitted by:
Dr. Steven C. Prochaska
Ohio State University Extension - Crawford County
117 East Mansfield Street
Bucyrus, OH 44820
419-562-8731
prochaska.1@osu.edu