Yield Response of Intensively Managed Corn and Soybean to Potassium Fertilizer Rate and Placement
IPNI-2001-CAN-ON24
06 Mar 2006
2005 Annual Interpretive Summary
Yield Response of Intensively Managed Corn and Soybean to Potassium Fertilizer Rate and Placement
The goal of this project is to examine the variation in corn and soybean yield response to varied input intensity applied across a field landscape. The objectives are to identify parts of the landscape that are most responsive to increased input levels, and to determine the particular constraints to crop growth at these locations during various stages of crop development. Seven strips of high-input treatments...comparing normal and high rates of potassium (K) across normal and deep placement, and normal and high inputs of nitrogen (N), phosphorus (P), and plant density...were applied in the fall of 2001 along the full length of a large field in preparation for corn and soybeans. The treatments were repeated for the 2003 and 2004 crops, rotating the corn and soybeans. Starting in the fall of 2004, tillage and fertility treatments were applied only to corn, with soybeans relying on residual fertility.
The 2005 season featured some of the highest corn yields achieved so far. The intensively-managed high K treatment yielded a field average of 190 bu/A. Yields responded well to K rates above provincial recommendations. Deep placement of K also boosted yield by 4% in contrast to little response in the first 3 years. Soil test levels for P and K are showing differences in response to rates applied. Soybeans on residual fertility in 2005 yielded 5% more following high input treatments than following normal recommendations.
The project is continuing in 2006, with cooperation of the Ontario Agri Business Association, adding new measures of environmental impact including residual soil nitrate. ON-24F