Effects of irrigation methods on yield and quality of alfalfa in arid northwest China

The present study was to explore the effects of different irrigation methods including subsurface drip irrigation(SDI), border irrigation(BI), sprinkler irrigation(SI), and CK on growth, quality and yield of alfalfa. The results showed that different irrigation methods had different effects on soil water content, and SDI treatment had the highest soil water content. In addition, this study found that different irrigation methods had greatly different effects on alfalfa quality, yield and water use efficiency. Dry yield of two cuttings alfalfa of SDI treatment was 4 815.87, 4 300.41 kg·ha-1, respectively. Compared with BI, SI and CK treatments, yield of two cuttings alfalfa of SDI increased by 10.56%, 14.92%, 95.26% and 13.64%, 23.60%, 120.85%, respectively (P＜0.05). Water use efficiency of two cuttings alfalfa of SDI treatment was 2.66, 2.50 kg·m-3, respectively. Compared with BI and SI treatments, water use efficiency of the two cuttings of SDI increased by 17.70%, 21.46% and 20.77%, 34.41%, respectively (P＜0.05).度SDI treatment had the lowest protein content and the highest fiber content, but crude protein yield of SDI treatment was significantly improved (P＜0.05). Crude protein yield of two cuttings alfalfa of SDI treatment was 816.13, 814.07 kg·ha-1, respectively. Compared with BI, SI,CK treatments, crude protein yield of two cuttings alfalfa of SDI increased by 2.38%, 5.84%, 61.90% and 10.90%, 18.83%,100.01%, respectively (P＜0.05). These results suggested SDI could improve the growth, crude protein yield, dry yield and water use efficiency of alfalfa. Therefore, SDI was more suitable for alfalfa planting in arid northwest China.