Building a Maximum Yield Cropping System for Corn, Wheat and Double-cropped Soybeans

The goal of this study is to develop a management program that increases crop yield, input efficiency, and profit potential in a predominantly no-till cropping system. This cropping system consists of four crops in three years: no-till soybeans in corn stubble, followed by minimum till wheat double-cropped with no-till soybeans, and then no-till corn.

The rotation clearly improved corn and soybean yields compared to continuous cropping. During 1997, a record yield of wheat was harvested, 151 bu/A, compared to the Maryland state average of only 60 bu/A.

Starting in 2000, nitrogen (N) use efficiency has appeared to improve when ammonium sulfate (AS) was blended into the N source, either urea or ammonium nitrate. Further studies are continuing to evaluate the AS effect. In 2001, hard red winter wheat yielded up to 123 bu/A with over 13% protein, when fertilized with a combination of soil and foliar N applications. In 2002, severe drought resulted in very poor yields.

In 2002, strip tillage with in-row ripping increased corn yields. The increase was partly due to increasing N availability, indicated by the response diminishing from 40 bu/A with no N applied to only 10 bu/A where 150 lb N/A was applied. Yields were not consistently increased by blending AS with ammonium nitrate.

Soybean yields in 2002 did not benefit from strip tillage applied to corn the previous year, but yields were 2 to 4 bu/A higher where N had been applied to corn the previous year, particularly with the AS form. Wheat yields in 2002 were boosted by an average of 7 bu/A application of sulfur (S) in the form of AS. Wheat yields with 100 lb N/A in a split application averaged 87 bu/A compared to 69 bu/A with 60 lb N/A applied all at once. Agrotain was more effective used with blends of urea and AS than when used with urea alone. MD-06F