地下滴灌水肥耦合对紫花苜蓿草产量及品质的影响

Effects of coupling of drip irrigation water and fertilizer on yield and quality of alfalfa in the yellow river irrigation district

为探讨滴灌条件下水肥互作模式对紫花苜蓿生产性能及营养品质的影响,设置4个水分梯度(W1、W2、W3、W4)和5个肥料梯度(F1、F2、F3、F4、F5),采用裂区试验设计,对水肥耦合条件下苜蓿生长性能、干草产量及品质进行测定,研究结果表明:适当的灌水施肥能显著提高紫花苜蓿株高、生长速度和分枝数,促进干草产量的形成和营养物质的积累。增大灌水量,灌溉水分利用效率减小,偏肥料生产力先增加后减小;增大施肥量,偏肥料生产力减小,灌溉水分利用效率先增加后减小。通过灰色关联度和模糊相似优先比评价分析可知,株高、生长速度和二级分枝数对干草产量的贡献较大,一级分枝数和叶茎比对干草产量的贡献较小;W3F2的水肥模式能够获得较高的干草产量(19831.83 kg·hm^-2)和蛋白含量(19.27%),还有利于提高灌溉水分利用效率(3.8 kg·m^-3)和肥料偏生产力(146.9kg·kg^-1)。回归寻优模型表明滴灌条件下紫花苜蓿生产最适宜的水肥范围为:灌水量6000~6500 m3·hm^-2,施肥量为250~320 kg·hm^-2。

This research explored the effects of water and fertilizer and their interaction on the growth and nutritional quality of alfalfa under drip irrigation.The design incorporated four water supply treatments(W1,W2,W3,W4,)and five fertilizer treatments(F1,F2,F3,F4,F5),and used a split-plot ANOVA design to analyze the alfalfa growth rate,hay yield and nutritional quality under the various combinations of water and fertilizer application.It was found that optimal irrigation and fertilization significantly increased the alfalfa plant height,growth rate and number of branches,enhanced hay yield and improved the nutrient status.Increasing the amount of irrigation decreased the irrigation water use efficiency,and the yield response to fertilizer increments increased initially and then decreased with successive water increments.Similarly,increasing the amount of fertilizer applied decreased the yield response to further fertilizer increments,while the irrigation water use efficiency increased initially and then decreased with successive fertilizer increments.Based on the Grey correlation and a‘fuzzy similarity priority ratio evaluation’analysis,it was concluded that the plant height,growth rate,and number of secondary branches contributed strongly to hay yield,and the number of primary branches and leaf to stem ratio contributed weakly to hay yield.The W3F2combination of water and fertilizer gave the highest hay yield(19832 kg·ha^-1)and protein content(19.27%),and also a comparatively high irrigation water use efficiency(3.8 kg DM·m^-3water)and fertilizer partial productivity(146.9 kg DM·kg^-1).A regression optimization model showed that the optimal range of water and fertilizer for alfalfa production under drip irrigation was an irrigation amount of 6000-6500 m3·ha^-1,and a fertilizer application rate of 250-320 kg·ha^-1.