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 water table 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≥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.