Ohio State University Extension Bulletin

Agronomic Crops Team On-Farm Research Projects 2000

Special Circular 179-01


Evaluation of USDA Soybean Inoculate
in a Modified Relay Intercropping System

Steve Prochaska, Extension Agriculture and Natural Resources Agent

Objective

To evaluate the effect of a new inoculate on soybean yield in a modified relay intercropping system.

Background

Modified Relay Intercropping is a system in which soybeans are planted into standing wheat around the time period of wheat pollination. Previous plot work over the last six years has resulted in soybean yields of 30 bushels per acre and wheat of 73 bushels per acre. (Yield averages over all treatments.)


Cooperator: Dave Brewer Fertilizer: 21-75-75 actual lb./A of
County: Crawford   NPK fall applied 85 lb./A
Soil Type: Blount silt loam   actual N as 28% spring
Tillage: No-till   applied
Previous Crop: Soybeans Varieties: Wheat ­ Hopewell
Soybean Herbicides: POST Select (5 oz./A)   Soybean ­ Pioneer 9306
  Firstrate (0.3 oz./A) Seeding Rates: Wheat ­ 120 lb./A
Wheat Herbicide: 2,4-D (1.5 pt./A)   Soybean ­ 90 lb./A
Wheat Row Width: 10 inch Wheat Planting Date: October 1, 1999
Soybean Row Width: 10 inch Harvest Date: July 5, 2000
  Wheat Yield: 73 bu/A
  Soybean Planting Date: 12, 2000
  Soybean Harvest Date: Oct. 14, 2000


Methods

New soybean inoculants have been reported to give a positive yield response in conventional tillage soybeans. As such, USDA inoculate at the labeled rate was mixed well into soybean seed, and soybeans were immediately interseeded into wheat on 6/12/2000. Soils were moist at the time of planting.

A completely randomized design was used with four replications of two treatments ‹ USDA inoculate and untreated soybeans. Plot size per treatment was 0.138 acres. A 15-foot Great Plains 1500 drill was used to plant both the wheat and the soybeans in 10-inch rows. A 20-inch tramline was established in the wheat to facilitate soybean planting into wheat.

Results


Treatments Yield (bu/A)

Control 37.2
USDA Inoculate 37.1

Significance (P = 0.05)
F <1, CV = 4.5%
NS

Summary

There were no significant yield differences between the soybeans inoculated with USDA inoculate and soybeans without inoculate in the modified relay intercropping system.

For additional information, contact:

Steve Prochaska, Agriculture and Natural Resources Agent
Ohio State University Extension, Crawford County
117 East Mansfield Street
Bucyrus, OH 44820
419-562-8731
prochaska.1@osu.edu


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