1. Dep. of Agronomy and HorticultureUniv. of Nebraska‐Lincoln Lincoln NE 68588 USA
2. USDA‐ARSCentral Great Plains Research Station Akron CO 80720 USA
3. USDA‐ARSGrassland Soil and Water Research Laboratory Temple TX 76502 USA
4. USDA‐ARSAgroecosystem Management Research Unit Lincoln NE 68583 USA
5. Nebraska Water CenterUniv. of Nebraska‐Lincoln Lincoln NE 68588 USA