施氮对高丹草-扁豆套作系统产量、品质和氮素利用效率的影响

Effects of Fertilizer Application on the Yield,Forage Quality and Nitrogen Use Efficiency of Sorghum bicolor×S.sudanense with Dolichos lablab Intercropping System

为探讨施氮量对高丹草-扁豆套作系统饲草产量、品质以及氮肥利用率的影响,本试验采用随机区组设计,主因素设高丹草(Sorghum bicolor×S.sudanense)/扁豆(Dolichos Lablab)套作(I)、高丹草(S)和扁豆(L)单作3种种植模式,副因素设0 kg·hm^(-2)(N 0,CK),180 kg·hm^(-2)(N 180),260 kg·hm^(-2)(N 260),340 kg·hm^(-2)(N 340)4个氮肥水平。结果表明:施氮有利于提高套作混合饲草的鲜/干产量和粗蛋白含量,与对照差异显著(P<0.05)。在N 260时套作混合饲草的产量、粗蛋白含量和氮肥利用效率达到最高,且显著高于单作高丹草(P<0.05)。施氮增加了混合饲草的粗纤维、中/酸性洗涤纤维含量,但在同一施氮处理下混合饲草的粗纤维、中/酸性洗涤纤维含量显著低于单作高丹草(P<0.05)。根据隶数函数综合评价表明,施氮肥260 kg·hm^(-2)时高丹草-扁豆套作系统混合饲草的品质最佳。

In order to explore the effect of nitrogen application level on the yield,forage quality and nitrogen use efficiency of Sorghum bicolor×S.sudanense with Dolichos Lablab intercropping system,a randomized block design was adopted in the experiment.The main factors were S.bicolor×S.sudanense with D.Lablab intercropping(I),S.bicolor×S.sudanense monocropping(S)and D.Lablab monocropping(L),and the side factors were 0 kg·hm^(-2)(N 0,CK),180 kg·hm^(-2)(N 180),260 kg·hm^(-2)(N 260),340 kg·hm^(-2)(N 340)of four fertilizer applications.The results show that fertilizer application was beneficial to enhance the fresh yield,hay yield and crude protein content of intercropped mixed forage,with a significant difference to those under N 0(P<0.05).Intercropping mixed forage yield,crude protein content and nitrogen use efficiency reached the highest under the N 260,and were significantly higher than those of S.bicolor×S.sudanense monocropping(P<0.05).Fertilizer application increased the contents of crude fiber,neutral detergent fiber and acid detergent fiber in mixed forage;but under the same fertilizer application,the contents of crude fiber and neutral detergent fiber and acid detergent fiber in mixed forage were significantly lower than those in S.bicolor×S.sudanense monocropping(P<0.05).According to the comprehensive evaluation of membership function method,comprehensive quality of S.bicolor×S.sudanense and D.Lablab intercropping under fertilizer application of 260 kg·hm^(-2) was the best on the total forage nutrients harvest.