Yield and Water Use Efficiency of Non- and Single-Irrigated Alfalfa with Ridge and Furrow Planting in Northern China

Ridge and furrow planting (REP) is a rainwater harvesting system that improves the yield and water use efficiency (WUF) of alfalfa (Medicago saliva L.) and other crops. Field experiments were performed to study the effects of REP under non- or single-irrigated (NI and SI) alfalfa production on yield, WUF, evapotranspiration (FT), soil water, and forage growth from 2010 to 2011. Three planting treatments were used, fiat bed, bare ridge, and plastic mulch ridge in the NI and SI fields that were referred to as FPNI, BRNI, and MRNI; and FPSI, BRSI, and MRS', respectively. For the NI field, BRNI and MRNI significantly increased the total forage yield in the 2 yr combined by 14 and 53%; and WUF by 17 and 74% compared with FPNI, respectively. The MRNI significantly increased the 2-yr combined yield by 34% and WUF by 55% compared with BRNI. There were no significant differences in the FT over the 2 yr among the three treatments. For the SI field, BRSI and MRSI significantly increased the total forage yield over the 2 yr by 53 and 107%; and WUF by 54 and 120% compared with FPSI, respectively. The MRSI significantly increased the yield over the 2 yr by 34% and WUF by 44% compared with BRNI. Only the FT value from the MRSI treatment was significantly lower than that from the FPSI or BRSI. Therefore, MRSI could improve the yield and WUF in alfalfa, with MRNI another option under rain-fed conditions.