Yield Response of Intensively Managed Corn and Soybean to Potassium Fertilizer Rate and Placement


22 Feb 2007

2006 Annual Interpretive Summary

Yield Response of Intensively Managed Corn and Soybean to Potassium Fertilizer Rate and Placement, 2006

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 K across normal and deep placement, and normal and high inputs of N, 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 in 2003 and 2004 under a corn-soybean rotation. 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 to date. 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. The 2006 season saw continued high yields under intensive management, while those under conventional management declined to only 90% as high. Postharvest soil nitrate levels ranged from 4 to 7 ppm and did not differ between intensive and conventional management. Soil test levels for P and K are showing differences in response to rates applied.

The project’s 5 years of yield data are beginning to supply valuable information demonstrating the economic and enviromental viability of intensive crop management. The project is continuing in 2007. ON-24F