Effects of irrigation quota and distribution on the production performance of alfalfa in the first growth year

This study explored the effects of irrigation quota and distribution on the production performance of alfalfa (Medicago sativa) in the first growth year. Three irrigation quota treatments were conducted: 3 750, 4 500, and 5 250 m3·hm-2. Three irrigation distribution models were conducted under the same irrigation quota of 4 500 m3·hm-2. The irrigation quota was divided before and after mowing at 35%+65%, 50%+50%, or 65%+35%. The leaf∶stem ratio and stem diameter were most strongly affected; these increased hay yield and improved nutritional quality. The next-strongest effects were on the growth rate and height in all growth traits of alfalfa. An irrigation quota of 4 500 m3·hm-2 enhanced hay yield and improved nutritional quality of first-year alfalfa. The 35%+65% irrigation distribution could significantly improve the hay yield and crude protein, reduce NDF and ADF(P0.05), and thus enhance the nutritional quality of alfalfa.