Water Use of Pearl Millet Forage in Response to Cultural Practice in the Semiarid Southern Great Plains.

As concerns increase over scarce water resources in the Ogallala aquifer of the semiarid Southern Great Plains, there is greater need for water efficient alternatives to traditional grain production systems. Forages in diversified flex cropping systems were identified to have greater water and precipitation use efficiencies than set rotations that do not include forage crops. Pearl millet (Pennisitum glaucum L.), a C^­₄ plant typically grown in semiarid climates, has potential to be utilized in flex systems. Review of literature on forage pearl millet indicated limited work comparing cultural practices in the region. The purpose of this work was to evaluate cultural practices intended to maximize water use efficiency (WUE) independent of a cropping system. The study hypothesis was that changes in cultural practice and soil management will influence soil surface evaporation and evaporative demand in the crop canopy. Responses can be observed in forage yield, water use, and WUE. Objectives were to evaluate irrigation level, row spacing, and tillage. Pearl millet was planted at two row widths, 76 and 19 cm, in till and no-till soil under three irrigation levels. Results from the first study year indicate WUE was not affected by cultural practice; however, irrigation level had the greatest effect on forage production. Forage yield did not respond to differences in row spacing, however, crop establishment was affected by tillage due to lack of seedling emergence in no-till. Water use and dry matter production were linearly correlated, having a regression slope of 7.76 kg ha^-1 mm^-1, however the r² value was low (0.21). This response was partly due to irregular plant stand because of a bad seed lot. Results from year two are forth coming.