The effects of different irrigation regimes on yield and silage quality of corn under semi-arid conditions

Abstract

The aim of this study was to evaluate the effects of different quantities of drip irrigation water on the corn yield and silage quality under semi-arid conditions. The seasonal evapotranspiration (ET_c) for the different irrigation regimes varied from 434 to 947 mm in 2004 and from 468 to 1003 mm in 2005 for total irrigation periods of 108 and 113 days, respectively. Combining data from both years, the relative evapotranspiration deficit (1−ET_a/ET_m) for different regimes was 19 to 54% in corn compared to the maximum seasonal ET_c when water was not limited in the (I₁₀₀) regime. During the course of both years, irrigation had an apparent effect on the total fresh silage yield (FSY), with yields increasing steadily from water stress to fully irrigated conditions, while silage yields increased linearly with the total depth of irrigation water applied between planting and harvest. Combining data from both years showed that the FSY was 35.0, 53.6, 83.3 and 88.9 t ha^-1 for I₂₅, I₅₀, I₇₅ and I₁₀₀, respectively. Moreover, the largest FSY recorded amongst these experiments at maximum seasonal yield in single treatment was 89.1 t ha^-1 in 2004 and 88.7 t ha^-1 in 2005. The water content decreased considerably in all but FSY, while the dry matters yield (DMY), organic matter (OM), acid detergent fiber yield (ADFY) and in vitro dry matter digestibility (IVDMD) increased. Furthermore, the study substantiated that the highest yield and silage quality were obtained at the full (I₁₀₀) irrigation regime.

Key words: Silage, deficit irrigation, yield, silage quality.