Growth, water productivity, nutritive value, and physiology responses of silage corn to water stress

Water is a crucial factor affecting expression of crop yield potential. A field experiment was conducted during 2014 and 2015 to determine the effect of limited water on growth, yield, water productivity (WP), nutritive value, and physiological parameters of silage corn (Zea mays L.) grown in a semi-arid region. Hybrid 'P8107HR' was planted in replicated plots under 100ETc (100% crop evapotranspiration), 80ETc, 60ETc, and limited 100ETc (100ETc from planting to V9, no water from V9 to R3, then 100ETc again) managed with a surface drip irrigation. Canopy height, leaf area index (LAI), specific leaf area (SLA), biomass yield, WP, and nutritive value were determined. Photosynthesis (A), stomatal conductance (gs), transpiration (E), and intrinsic WP (iWP) were obtained with an infrared gas analyzer from V14 to R2 stages. Relative water content (RWC) of leaves was determined at V8, V12, VT, and R3 stages. Results showed that canopy height and biomass yield were greatly affected by water stress. Biomass yield decreased by 40% in the limited 100ETc treatment compared to 100ETc, with no effect of irrigation on nutritive value. Water-stressed plants from V14 to R2 were affected in their ability to perform gas exchange and exhibited changes in crop growth and biomass yield. RWC was affected by water stress, mostly under 60ETc at V8 (71%) and VT (78%). Overall, limited water at late vegetative and early reproductive stages affected physiology and yield of silage corn, indicating that irrigation timing is a key factor for optimizing silage corn production in water-scarce regions.