Crop Yield Results from Simulated Rain Applications to Agricultural Plots in Illinois


  • Stanley A Changnon Illinois State Water Survey Champaign, Illinois
  • Steven E Hollinger Illinois State Water Survey Champaign, Illinois


Ten different levels of rainfall were applied (during 1987, 1988, and 1989) to agricultural plots in central Illinois to discern effects on corn and soybean yields. Increases in rainfall during a hot dry summer (June-August 1988) revealed sizable yield gains. For one inch of added rainfall, the yields increased 10 bu/acre for corn and 4 bu/acre for soybeans. In a summer of near average rain (1989), the increases were less, about 5 bu/acre for corn and 3 bu/acre for soybeans. When summer rainfall exceeded 14 inches, yields of both crops were decreased. The various rainfall tests revealed that rain increases done only on days when natural rainfall was </= O.1 inch provided no detectable yield increases, whereas a 40% increase on all rain days (the largest increase tested) produced the greatest crop yield increase (up to the 14-inch optimum). Corn yields reacted very favorably to added rains days with >1.0 inch of rain.




Scientific Papers