渗灌对宁夏引黄灌区苜蓿生长性状及水分利用率的影响

研究渗灌对苜蓿土壤含水量、生产性能及水分利用效率的影响对苜蓿的科学渗灌具有重要意义。以宁夏引黄灌区紫花苜蓿为对象,对渗灌定额350(S₃₅)、400(S₄₀)、450(S₄₅)和500(S₅₀) m³·667 m^-2和漫灌定额800 m³·667 m^-2(CK)下的土壤含水量动态,苜蓿生长性状、饲用品质及灌溉水利用效率进行了研究。结果表明:1)整个生育期内,CK的土壤含水量和耗水量最高,S₄₅的土壤含水量较低,渗灌较传统漫灌有利于保持土壤水分;CK在0~20 cm土层土壤水分变异系数最大,各渗灌0~40 cm土层变异较小,渗灌土壤含水量随土层加深而下降,土壤水分变异低于漫灌;2)渗灌可促进苜蓿的叶茎比、分枝数、叶面积指数、根系生物量以及粗蛋白含量的增加,降低酸性洗涤纤维含量,这在S₄₅和S₅₀下总体表现更明显;3)除S₃₅外,其他渗灌的苜蓿草产量和粗蛋白产量均较对照有不同程度增加,说明适宜的渗灌量可提高苜蓿草产量和粗蛋白产量,提高灌溉水利用效率和苜蓿经济效益。研究认为,450 m³·667 m^-2左右渗灌定额是宁夏引黄灌区苜蓿渗灌的适宜灌水量。

Effects of infiltration irrigation on growth characters and water use efficiency of alfalfa in the Ningxia Yellow River diversion irrigation area

It is important to study the effects of infiltration irrigation on soil water content, production performance and water use efficiency of alfalfa for scientific evaluation of infiltration irrigation. This study evaluated the performance of alfalfa in the Ningxia Yellow River diversion irrigation area under a range of irrigation treatments. Specifically, infiltration irrigation application rates of 350 (S₃₅), 400 (S₄₀), 450 (S₄₅) and 500 (S₅₀) m³·667 m^-2 were compared with a flood irrigation allocation of 800 m³·667 m^-2 (CK). We measured soil moisture content, growth characters, feed quality and irrigation water use efficiency. The results can be summarized as follows: 1) Over the whole growth period, CK had the highest soil water content and water consumption, while S₄₅ had lower soil water content, and infiltration irrigation was used soil water more efficiently than traditional flooding irrigation. The coefficient of variation for soil water content of the CK treatment was the largest in the 0-20 cm soil layer, while the coefficient of variation for soil water content for each infiltration irrigation rate in the 0-40 cm soil layer was smaller. Under infiltration irrigation the soil water content decreased with the depth within the soil profile, and its coefficient of variation was lower than that of flood irrigation. 2) Infiltration irrigation resulted in an increase in leaf-stem ratio, branch number, leaf area index, root biomass and crude protein content, and a decrease the content of acid detergent fiber of alfalfa. This was more obvious under the S₄₅ and S₅₀ treatments. 3) Except for the S₃₅ treatment, the alfalfa herbage and crude protein yields under infiltration irrigation were higher than in the CK treatment. An appropriate irrigation rate improved the alfalfa herbage and crude protein yield, and irrigation water use efficiency, with a resulting economic benefit. Based on results from this study, the irrigation allocation of 450 m³·667 m^-2 is the suitable irrigation quantity of alfalfa infiltration irrigation in Ningxia Yellow River diversion irrigation area.