An analysis of eight years of soil moisture over three agroecosystems at Mead, NE

Soil moisture is a critical parameter for crop growth and development. Soil moisture sensors were installed at four depths (10 cm, 25, 50 cm, and 100 cm) in Intensive Management Zones (IMZ's) at three different agroecosystems as part of the Carbon Sequestration Project at Mead, NE. The three agroecosystems are as follows: an irrigated, continuous maize (ICM) field, an irrigated, maize-soybean rotation (IMS), and a rainfed, maize-soybean rotation (RMS). Volumetric water content was strongly correlated at 10, 25, and 50 cm within RMS and at 10 and 25 cm within and between the IMZ's at ICM and IMS. Moderate correlations existed at 10 and 25 cm between IMS and RMS. Correlations were weak to negligible elsewhere. The average volumetric water content at IMS was almost identical in growing seasons (planting to harvest) planted to maize and soybeans and was slightly higher than ICM in years where maize was the common crop. The average volumetric water content at RMS was also almost identical in seasons planted to maize and soybeans but was generally lower than the water content at IMS and at ICM, when maize was the common crop. Average volumetric water content during the reproductive phase was also a good predictor of grain yield with R² values as high as 0.83 and 0.89 for maize and soybeans respectively.