不同叶面肥对紫花苜蓿生长、产草量和品质的影响及效益比较

喷施叶面肥是提高苜蓿产草量和品质的有效措施之一。为探明不同叶面肥成分对紫花苜蓿（Medicago sativa L.）生长、产草量和品质的影响，并筛选紫花苜蓿优质高产的叶面施肥方案，本试验以生长第2年的‘东农1号’紫花苜蓿（Medicago sativa L.‘Dongnong No.1’）为材料，在春季返青期一次性土壤施肥基础上，于刈割前20天分别喷施苜蓿专用叶面肥（自主研制，专利申请号：201810124670.2）、0.3%尿素、0.5%磷酸二氢钾、0.3%尿素+0.5%磷酸二氢钾、0.3%尿素+0.1%硫酸亚铁+0.05%钼酸铵、0.5%磷酸二氢钾+0.1%硫酸亚铁+0.05%钼酸铵，0.3%尿素+0.5%磷酸二氢钾+0.1%硫酸亚铁+0.05%钼酸铵这7种叶面肥（分别简称叶面肥A，B，C，D，E，F，G），以喷施清水为对照，每年刈割3茬，观测不同叶面肥对‘东农1号’紫花苜蓿高度、茎叶比、产草量和营养品质的影响，并进行经济效益比较分析。结果表明：喷施叶面肥均可显著提高紫花苜蓿垂直高度、产草量和粗蛋白含量；其中叶面肥G处理下，全年总干草产量达14 595.81 kg·hm^-2，比对照提高17.70%；平均粗蛋白含量为25.43%，比对照提高3.12%。叶面肥A处理纯增经济效益和产投比分别达2 414.57元·hm^-2和2.63，是叶面肥G处理的2.65倍和8.77倍。经过综合比较分析，在寒地黑土农区喷施紫花苜蓿专用叶面肥（A处理）相对投入较少，产出较多，综合效益最高。

Effects of Spraying Different Foliar Fertilizers on Growth,Yield and Quality and Economic Benefit of Alfalfa

Spraying foliar fertilizer is one of the effective measures to improve the yield and quality of alfalfa. We used the second year growing Medicago sativa L. ‘Dongnong No.1’ as the experimental material,to explore the impacts of spraying fertilizer to leaves on the growth,yield and quality of alfalfa,and screen foliar fertilization schemes with high quality and high yield. Seven kinds of foliar fertilizers were applied to soil before 20 days of the returning green stage of alfalfa. The seven kinds of foliar fertilizers were:Special foliar fertilizer for alfalfa (A),0.3% urea (B),0.5% potassium dihydrogen phosphate (C),0.3% urea+0.5% potassium dihydrogen phosphate (D),0.3% urea+0.1% ferrous sulfate+0.05% ammonium molybdate (E),0.5% potassium dihydrogen phosphate+0.1% ferrous sulfate+0.05% ammonium molybdate (F),and 0.3% urea+0.5% potassium dihydrogen phosphate+0.1% ferrous sulfate+0.05% ammonium molybdate (G). Spraying water was conducted as the control treatment. The alfalfa was mowed three times per year,the effects of different kinds of foliar fertilizers on alfalfa height,stem/leaf ratio,grass yield and nutrient quality were examined,and their economic effects analysis were conduted. The results showed that the utilization of foliar fertilizers could effectively promote the vertical height,grass yield and crude protein of alfalfa. The total hay yield of G treatment was 14 595.81 kg·hm^-2,which was 17.70% higher than that of the control treatment;and its average crude protein content was 25.43%,which was 3.12% higher than the control. The pure increase of economic benefit and production/investment ratio of foliar fertilizer A was the highest,with 2 414.57 yuan·hm^-2 and 2.63 respectively,which were 2.65 times and 8.77 times of the G treatment,with the highest comprehensive benefit. After comprehensively considering of the low input and high output,we suggest spraying the special foliar fertilizer in alfalfa planting (A treatment) in black soil area of the cold region of northeast China.