灌水下限对紫花苜蓿产量、品质及水分利用效率的影响

Effects of the Irrigation Low Limits on Alfalfa Yield, Quality and Water Use Efficiency

【目的】提高华北地区紫花苜蓿水分利用效率,兼顾产量与品质。【方法】于2018年4―9月,在河北涿州中国农业大学教学实验场,以紫花苜蓿品种WL363HQ为试验材料,开展紫花苜蓿田间灌溉试验。试验设置3个灌水处理:W1处理,灌水下限45%FC(田间持水率),灌水上限90%FC;W2处理,灌水下限60%FC,灌水上限90%FC;W3处理,根据当地生产经验定额灌溉为39 mm,研究了不同灌水下限对紫花苜蓿生长、产量和品质的影响。【结果】建植第5年的紫花苜蓿,全生长季需水量511.9 mm。苜蓿细根根系主要分布在0~40 cm土层,0~20 cm土层根系密度最高。灌水对第1、第2茬及全年产量没有显著影响(P>0.05),对第3茬产量有显著影响(P<0.05)。第1、第2、第3茬内采用W1处理苜蓿水分利用效率最高。不同灌水处理对苜蓿粗蛋白量没有显著影响(P>0.05),减少灌水量能增加苜蓿相对饲喂价值。【结论】建议华北地区紫花苜蓿第1、第2、第3茬采用45%FC灌水下限,第4茬采用60%FC灌水下限。

【Objective】We aimed to improve the water use efficiency, yield and quality of alfalfa in North China Plain.【Method】From April 2018 to September 2018, a field irrigation experiment of the alfalfa WL363 HQ was conducted at experimental station of China Agricultural University in Zhuozhou, Hebei Province, China, to evaluate the effects of different irrigation low limits on alfalfa growth, yield and quality. In the experiment, three irrigation treatments(W1, W2 and W3) were irrigated based on the field capacity(FC) in the root zone soil and the farmer’s normal practices, respectively. The soil water was supplied to 90% FC when it dropped to 45% FC and 60% FC for W1 and W2, respectively. W3 was irrigated on the basis of the local farmer’s experience.【Result】Annual water requirement of 5 th year alfalfa was 511.9 mm. The main fine roots of alfalfa distributed in 0 to 40 cm soil layer. The highest root density occurred in the 0 to 20 cm of soil layer. Irrigation amount had insignificant effect on yields of the first, second cutting and annual yields(P>0.05), except for the yields of third cutting(P<0.05). Applying W1 treatment in the first, second and third cuttings could obtain the highest water use efficiency of alfalfa. Different irrigation treatments had no significant effect on the crude protein content(P>0.05). Reducing irrigation amount increased the relative feeding value. 【Conclusion】It was recommended that irrigation low limit of 45% FC in the first, second and third cutting and 60% FC in the fourth cutting were applied for alfalfa irrigation management in the North China Plain.