Spatial Patterns in Soil Water Availability in Irrigated Maize.

Spatial variability in plant available water and crop water usage make irrigation management difficult. Technology exists to spatially vary water inputs but our understanding of water redistribution, availability, and crop use within spatially variable landscapes limits our application of this technology. A production field in eastern Nebraska was used to measure soil water status during a growing season. A dense georeferenced electrical conductivity map of the field was used to select 20 sites across the field that captured variation in soil properties. At each site soil water sensors were installed at depths of 30, 60, 90, and 120 cm. Soil moisture was recorded every six hours. Changes in soil water availability during the growing season are reported and potential uses for variable irrigation are discussed.