Farmers Use ISU Research To Adjust Soybean Planting Dates, Rates

Paul Kassel, Extension Field Agronomist, Northwest

Problem Statement: 

Farmers seek to maximize soybean yields and reduce input costs.  Soybean yield performance has lagged in comparison with corn yield performance for many farming operations.  Farm operators desire research based education that will enable them to increase soybean yields. 

Soybean seed costs have increased three fold in the last ten years.  Farm operators have an interest in reducing seeding rates to decrease costs.

Programmatic Response: 

Research at ISU has shown that soybeans planted in early May yield 5 to 7 bu/a more than when planted in late May.  Other ISU research has shown that a seeding rate of 140,000 seeds per acre has shown similar yields to a planting rate of 160,000 seed per acre or more.  I included this information on three radio programs, two Field and Feedlot newsletters articles, two Crops Bulletin newsletters, a Crop Advantage Series meeting and two field days.


A random survey of thirteen 2008 Crop Advantage Series attendees (who also attended in 2007) showed that nine of them planted soybeans earlier than in previous years.  These nine attendees reported that they made $23.85/acre more on 2977 acres as a result of an earlier planting date.   Six of the 13 reported that they reduced seeding rates by 13,000 seeds/acre on 2615 acres for a savings of $5.29/acre. The total impact reported by the thirteen survey respondents in this report is $84,835.00.

100 Corn and Soybean Production and Protection

Page last updated: January 7, 2008
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