Effect of Cropping Systems on Water Use and Yield of Corn and Soybean Grown in a Humid and Temperate Climate.

Diversifying corn and soybean cropping systems with extended rotations is an option to enhance the efficiency of resources use in crop production. The approach is particularly relevant to soil water conservation and crops water use in rainfed agriculture. The effect of cropping systems on water use and yield of corn and soybean grown in a humid and temperate climate was investigated. The study was conducted at the University of Minnesota Southwest Research and Outreach Center located near Lamberton, MN during the 2013, 2014, and 2015 growing seasons. The treatments studied included an extended 4-yr crop rotation (oat/alfalfa-alfalfa-corn-soybean) using organic inputs (ORI) and high external inputs (HEI) and the traditional 2-yr corn-soybean rotation (HEI), with a prairie as the control treatment. Response variables included yield and root length density of corn and soybean, soil moisture monitored at 10, 20, 40, 60, 100, and 200 cm using moisture-temperature sensors connected to a data logger for continuous measurement, and calculated and estimated water use of crops. Our results suggest that the intensification of cropping systems has a positive effect on crops water use and yield.