Yield Potential and Water Use Efficiency of Alternate Rotation Crops in the Semiarid Environment of Southwestern United States

Abstract

Highlights Water use efficiency and yield potential of 10 rotation crops were tested under dryland and fully irrigated conditions. Pearl millet in grasses, cowpea and sesbania in legumes had great potential as rotation crops with greater yields and WUEs. Irrigation improved water use efficiency of crops compared to dryland conditions. Abstract. Unpredictability in weather patterns prompted a need for testing diverse crops with broad range adaptability to introduce into the existing cropping systems or to innovate alternate cropping systems in the southwestern United States. Such crops suitable for system integration should preferably be dual-purpose and resource-use efficient. Keeping this in view, a two-year study was conducted at NMSU Rex E. Kirksey Agricultural Science Center, Tucumcari, New Mexico, comprised of 10 annual crop species including grasses, legumes, and oilseed crops. The study aimed at researching yield potential and water use efficiency of the selected crops under dryland and limited irrigated conditions in the semiarid, subtropical environment. Results suggest that both crop species and water regime (irrigated vs. dryland) had significant effects on seed and biomass yield and water use efficiencies (WUE) (P<0.05). Seed and biomass production under dryland conditions were significantly influenced each year by amount of precipitation received. Pearl millet [Pennisetum glaucum (L.) R. Br.] had consistently greater seed and biomass yields and WUEs than the other crops. Cowpea (Vigna unguiculata) and sesbania (Sesbania sesban) proved to be viable legumes with the advantage of greater biomass yields and water-use efficiency (WUEs) compared to other the legumes tested (P<0.05). For a balanced livestock diet, pearl millet+cowpea intercrop combination is a good option with greater yields and WUEs. Integrating these rotation crops into the traditional winter wheat cropping systems or alternate cropping systems may provide a significant benefit to producers in the semiarid southwestern United States. Keywords: Alternate crops, Summer rotation, Water-use efficiency, Yield potential.