Dr. Steve Prochaska, Extension Agriculture and Natural Resources Agent
To evaluate the effect of Modified Relay Intercropping (MRI) on wheat yield in a 15-inch-row spacing
| Test Site: | Ohio State University | Soil test: | pH 5.8, P 21 ppm, |
| Unger Farm | K 163 ppm | ||
| County: | Crawford | Fertilizer: | 127-69-60 actual NPK |
| Soil type: | Pewamo clay loam and | applied per acre | |
| Blount silt loam | Planting date: | October 2, 2001 | |
| Tillage: | Disk | Planting rate: | 120 lb/A |
| Previous crop: | Soybeans | Row width: | 15 inch |
| Variety: | See table | Herbicide: | 2,4-D 1 pt/A |
| Harvest date: | July 8, 2002 |
A completely randomized design with six replications in small plots (5.5 x 50 feet) in each of three years was used to evaluate the effect of MRI on wheat yield. Treatments were 15-inch-row wheat and 15-inch-row wheat interseeded with soybeans. Wheat and soybeans were planted with a three-point hitch mounted tool bar planter equipped with sunflower openers. Soybeans were interseeded June 5, 2002, with the same planter used to seed wheat. Wheat harvest was completed in late June or early July with a research plot combine.
Table 1. Three Years of 15-Inch Row Spacing Wheat Yields and Summary.
| Not Intercroppped | Intercropped | Difference | LSD (0.05) | |
| Year and Variety | (bu/A) | (bu/A) | (bu/A) | (bu/A) |
| 2000 I9824 | 70.8 | 62.0 | 8.8 | 3.4 |
| 2001 Agra 962 | 79.2 | 68.0 | 11.2 | 4.2 |
| 2002 Agra 962 | 76.8 | 71.4 | 5.4 | 3.4 |
| Average | 75.6 | 67.1 | 8.5 | |
What level of wheat yield can be expected from wheat grown in wide rows that is also intercropped? This question is important to producers in wheat/soybean double crop systems. In each of the three years of this study, wheat grown in a modified relay intercrop system yielded significantly less than wheat grown in the same spacing conventionally.
Interseeded wheat produced 8.5 bu/A lower yield than non-interseeded wheat when both were grown in rows spaced 15 inches apart.
For further information, contact:
Dr. Steve Prochaska
Ohio State University Extension
117 E. Mansfield St.
Bucyrus, Ohio 44820
prochaska.1@osu.edu