灌溉定额分配及水磷耦合对滴灌苜蓿 生长规律的影响

【目的】 研究不同灌溉定额分配及水磷耦合对滴灌苜蓿(Medicago sativa L.)生长规律的影响。【方法】 设3种灌溉梯度,分别为:5 250 m³/hm²(W₁)、6 000 m³/hm²(W₂)、6 750 m³/hm²(W₃),在灌水量为6 000 m³/hm²(W₂)下,设3种灌溉定额分配模式:(1)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%(F₁)、(2)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%(F₂)、(3)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%(F₃)。在三种灌溉梯度下分别设3种施磷模式为:施P₂O₅ 50 kg/hm²(P₁)、100 kg/hm²(P₂)、150 kg/hm²(P₃)。【结果】 不同灌溉定额分配条件下,各茬次F₂处理苜蓿植株达到最快生长速率的天数最少为17~18 d,F₁处理苜蓿生物量的增长空间最大,且受灌溉定额分配的影响最小;不同水磷耦合条件下,各茬次W₃P₂处理苜蓿植株达到最快生长速率的天数最少为15~16 d,W₁P₃处理、W₂P₃处理、W₃P₃处理苜蓿生物量的增长空间最大,W₃P₃处理受水磷影响最小。【结论】 在苜蓿达到最大生长速率15~18 d时进行水肥管理效果最佳,且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%,以及适宜灌溉量(6 000 m³/hm²)与施磷量(P₂O₅ 100 kg/hm²)的有效耦合,均有利于建植第二年滴灌苜蓿生长潜力的有效发挥。

Effects of Irrigation Quota Distribution and Water-phosphorus Coupling on the Growth Regularity of Alfalfa under Drip Irrigation

【Objective】 This study aims to explore the effects of irrigation quota distribution and water-phosphorus coupling on the growth regularity of alfalfa (Medicago sativa L.) under drip irrigation. 【Method】 Three irrigation gradient treatments were conducted: 5,250 m³/hm² (W₁), 6,000 m³/hm² (W₂), and 6,750 m³/hm² (W₃), respectively. Under the irrigation amount of 6,000 m³/hm² (W₂), irrigation amount were distributed with three different modes: (1) 35% of the total irrigation amount before mowing and 65% of the total amount irrigation water after mowing (F₁). (2) 50% of the total irrigation amount before mowing and 50% of the total amount irrigation water after mowing (F₂). (3) 65% of the total irrigation amount before mowing and 35% of the total amount irrigation water after mowing (F₃). Three kinds of phosphorus patterns were set up under three irrigation gradients, and the contents of P₂O₅ were 50 kg/hm² (P₁), 100 kg/hm² (P₂) and 150 kg/hm² (P₃), respectively.【Result】 In the different irrigation quota distribution conditions, the days of reaching the fastest growth rate of alfalfa plants under F₂ treatment were at least 17-18 days, and the alfalfa biomass of F₁ treatment had the biggest growth space, which was also the least influenced by irrigation quota distribution of different mowing. In the different water-phosphorus coupling conditions, the maximum growth rate of alfalfa plants reached at least 15-16 d at each time of W₃P₂ treatment and the alfalfa biomass of W₁P₃ and W₂P₃ and W₃P₃ treatments had the biggest growth space, among which, W₃P₃ treatment was the least influenced by water and phosphorus of different mowing.【Conclusion】 When the alfalfa reached the maximum growth rate on 15 th to 18 th days, the effect of water fertilizer managements were the best, and the irrigation with 35% of the total irrigation amount before mowing and 65% of the total amount irrigation water after mowing, and effective coupling between suitable irrigation amount (6,000 m³/hm²) and phosphorus application amount (P₂O₅ 100 kg/hm²) were beneficial to the effective development of alfalfa growth potential under drip irrigation in the second growth year.