优化灌溉制度提高苜蓿种植当年产量及品质

Optimal irrigation regime improving yield and quality of alfalfa in year of sowing

为探讨灌溉定额及分配对滴灌苜蓿种植当年生产性能及水分利用效率的影响,该研究设3种滴灌灌溉定额,分别为3 750（W1）、4 500（W2）、5 250 m3/hm^2（W3）,且在W2处理下,设3种灌溉定额分配模式（Q1：刈割前灌溉本茬次总灌水量的35%＋刈割后灌溉本茬次总灌水量的65%;Q2：刈割前灌溉本茬次总灌水量的50%＋刈割后灌溉本茬次总灌水量的50%;Q3：刈割前灌溉本茬次总灌水量的65%＋刈割后灌溉本茬次总灌水量的35%）。结果表明,滴灌苜蓿种植当年,不同灌溉量条件下,苜蓿的株高、叶茎比、茎粗、生长速度、干草产量、粗蛋白（crude protein,CP）含量均为W3〉W1处理,中性洗涤纤维（neutral detergent fiber,NDF）、酸性洗涤纤维（acid detergent fiber,ADF）含量为W3〉W2处理,水分利用效率（water use efficiency,WUE）为W1〉W3处理;不同灌溉定额分配条件下,苜蓿的株高、叶茎比、茎粗、生长速度、干草产量、CP、WUE均为Q1〉Q3处理,且Q1处理的干草产量最高达到9 916-10 172 kg/hm^2,WUE为3.31-3.39 kg/（mm·hm^2）,

In this study, the effects of irrigation quota and its distribution on production performance and water use efficiency of alfalfa in the year of sowing were investigated. Drip irrigation quota treatments included 3 750（W1）, 4 500（W2） and5 250 m3/hm^2（W3）, respectively. Under the irrigation quota of 4 500 m3/hm^2, irrigation quota were distributed with 3 differen modes： 1） 35% of the total irrigation amount before mowing and 65% of the total amount irrigation water after mowing（Q1）2） 50% of the total before mowing and 50% of the total after mowing（Q2）; 3） 65% of the total of the total before mowing and35% of the total after mowing（Q3）. The irrigation was conducted about 8-10 d before mowing and about 5-6 d after mowing The experiment was conducted in Experimental Station of Shihezi University in 2014 and Demonstration Plot of Tianye Group in 2015. Measurements included plant height, hay yield, leave-stem ratio, stem diameter, crude protein, acid detergent fiber and neutral detergent fiber. In addition, water use efficiency was calculated based on evapotranspiration. The results showed that the plant height, leave-stem ratio, stem diameter increased with irrigation. There was significant difference between W3 and W2 treatments（P〈0.05）. Under the W2 treatment, the Q1 treatment could promote the growth of alfafa, showing high plan height, leave-stem ratio, stem diameter, and growth rate. The hay yield was the highest in the W3 treatment, and lowest in the W1 treatment, and the highest in the Q1. It suggested that the large irrigation before mowing and the small irrigation after mowing did not facilitate the hay production. The water use efficiency decreased with the increase of irrigation quota. The water use efficiency of W3 was significantly lower than that of W1（P〈0.05）. The Q1 treatment had significantly higher water use efficiency than the Q3（P〈0.05）. The acid and neutral detergent fibers in the W3 were significantly higher than those in the W1 and W2（P〈0.05）. Those in the Q3 were significantly higher than that in the Q1（P〈0.05）. The crude protein in the Q1 was higher than that in the Q3（P〈0.05）. Thus, the Q1 treatment could increase the crude protein but lower the acid and neutra detergent fiber contents. In sum, the suitable irrigation amount（4500 m3/hm^2） was conducive to increase the hay yield of alfalfa in the year of sowing and maintain high crude protein content and low acid and neutral detergent fiber content. Under the irrigation quota of 4500 m3/hm^2, the hey yield of Q1 treatment could be as high as 9 916-10 172 kg/hm^2, and the WUE of Q1 treatment was 3.31-3.9 kg/（mm·hm^2）. Thus, the irrigation with 35% of the total of the same stubble before mowing and65% of the total of the same stubble after mowing was conducive to increasing the hay yield and improving the nutritional quality of alfalfa in the year of sowing.