The Loess Plateau is one of the most important rainfed regions in China, but rainfall is the most significant factor limiting crop production. In this region rainfall from July to September accounts for 56% of the annual total, providing enough water resources for the growth of autumn-sown crops. Although increasing forage production with autumn sown crops is considered an important means of balancing crop forage and livestock management, suitable species with high yields and good water use efficiency (WUE) are not well defined.
The relationship between yield and water use efficiency has been shown to vary with plant species and harvest time (Siahpoosh et al. 2011), indicating that good water management can increase yields. It is therefore necessary to establish efficient water management strategies to increase the yield of autumn-sown crops. The objective of this study was to evaluate annual production of forage crops under autumn sowing conditions and identify their optimal WUE, based on crop production and evapo-transpiration (ET)