Crop yield evaluation under controlled drainage in Ohio, United States

Controlled drainage (CD) is an important practice for reducing nutrient loading to surface water bodies across the midwestern United States. There may also be a positive crop yield benefit, which could add an incentive for adoption of this practice. The objective of this multienvironment trial was to assess yield stability and yield performance of CD in northwest Ohio, United States. The trial was a split-plot experiment with environments as whole plots (randomization unit). The main plot factor was crop with three levels: corn (Zea mays L.), popcorn (Zea mays L. v a r. everta), and soybean (Glycine max [L.] Merr.). The subplot factor was drainage management with two levels: conventional free drainage (FD) and CD. The design of the main plot factor was a completely randomized design. Mixed model analysis showed that CD management produced a statistically greater (p-value = 0.0246) crop yield compared to FD management over 23 site-year environments during 2008 to 2011. Interaction between drainage management and crop was not significant, implying that CD management had the same yield-increasing effect for all crops. The CD management provided 3.3%, 3.1%, and 2.1% greater yield for corn, popcorn and soybean, respectively, relative to the FD management. The stability analysis based on 23 environments suggested that the drainage managements were not different in yield stability, though a larger number of environments are needed to make a more accurate assessment of yield stability. Area of influence analysis indicated that CD can provide more profit than FD for relatively flat fields where the influence of CD extends over the entire field. In conclusion, CD provided crop yield advantage over FD across different environments in northwest Ohio.