Influence of water table management on corn and soybean yields

A 2-year field study was conducted in eastern Ontario to evaluate the effect of watertable management (WTM) on the yields of strip-cropped corn (Zea mays L.) and soybean (Glycine max Merr.). The WTM treatments consisted of two subirrigation treatments with water table controls set at 0.50 m (CWT0.5) or 0.75 m (CWT0.75) from the soil surface, and a free drainage (FD) treatment (water table greater than or equal to 1.00 m below the soil surface. Both corn and soybean yields were higher with CWT than with FD for both years. In 1995, corn yields were 13.8% and 2.8% greater and soybean yields 8.5% and 12.9% greater, respectively, in the CWT0.5 and CWT0.75 plots than in the FD plots. Similarly, in 1996, corn yields were 6.6% and 6.9% greater and soybean yields 37.3% and 32.2% greater, respectively, in the CWT0.5 and CWT0.75 plots than in the FD plots. Yield increases obtained during the study were attributed to greater crop water uptake in the CWT plots as a result of the higher water tables. Comparison of 1995 and 1996 weather data with the long-term average of the region shows that the years of study had wetter-than-average conditions in the critical months of July and August, and that the yield increases due to WTM could be expected to be even greater during drier years. (C) 2000 Elsevier Science B.V. All rights reserved.