Pearl Millet Forage Water Use Efficiency

Pearl millet (Pennisitum glaucum L.) is a warm season C₄ grass well adapted to semiarid climates where concerns over scarce and depleting water resources continually prompt the search for water efficient crop management to improve water use efficiency (WUE). A two-year study was conducted in the Southern Great Plains, USA, semi-arid region, to determine optimum levels of irrigation, row spacing, and tillage to maximize WUE and maintain forage production in pearl millet. Pearl millet was planted in a strip-split-plot factorial design at two row widths, 76 and 19 cm, in tilled and no-till soil under three irrigation levels (high, moderate, and limited). The results were consistent between production years. Both WUE and forage yield were impacted by tillage; however, irrigation level had the greatest effect on forage production. Row spacing had no effect on either WUE or forage yield. The pearl millet water use-yield production function was y = 6.68 × x (mm) − 837 kg ha⁻¹; however, a low coefficient of determination (r² = 0.31) suggests that factors other than water use (WU), such as a low leaf area index (LAI), had greater influence on dry matter (DM) production. Highest WUE (6.13 Mg ha⁻¹ mm⁻¹) was achieved in tilled soil due to greater LAI and DM production than in no-till.