种植方式与施氮对西北旱区饲草作物产量、品质和水分利用的影响

Effects of planting methods and nitrogen application on forage crop yield,quality and water use in arid area of northwest China

间作和施氮是提高饲草作物产量和品质的重要措施,然而,在西北旱区青贮玉米-豆科作物间作系统的适宜施氮量尚不明确。本试验采用二因素随机区组设计,设置3个种植方式(青贮玉米-拉巴豆间作,silage corn/Dolichos lablab intercropping,SL;青贮玉米-秣食豆间作,silage corn/fodder soybean intercropping,SF;青贮玉米单作,silage corn monoculture,S)和4种施氮水平(N1:0 kg hm^(-2);N2:120 kg hm^(-2);N3:240 kg hm^(-2);N4:360 kg hm^(-2))。分析种植方式和施氮水平对饲草作物产量、品质和水分利用的影响,探索适宜西北旱区的玉-豆间作组合及施氮量。结果表明,与S处理相比,2019年和2020年SL处理的干草产量分别显著增加8.94%和8.68%,水分利用效率分别显著增加12.28%和8.90%。间作较单作显著提高了饲草作物的粗蛋白和粗灰分含量,显著降低了淀粉和中性洗涤纤维含量。施氮处理较不施氮显著提高了饲草作物的干草产量、粗蛋白、淀粉和粗脂肪含量,显著降低了中性和酸性洗涤纤维含量,而对粗灰分含量无显著影响。2019年N2、N3和N4的干草产量较N1分别显著增加30.30%、56.19%和53.95%,2020年分别显著增加22.02%、60.54%和51.83%。N3和N4的WUE显著高于N1和N2,而N3与N4无显著差异。所有处理中,SL-N3获得了最高的2年平均干草产量(33.10 t hm^(-2))、粗蛋白含量(10.01%)和水分利用效率(62.50 kg hm^(-2)mm^(–1))。综上所述,SL-N3是一种适合西北旱区青贮玉米生产的种植管理模式。

Intercropping and nitrogen application are important measures to improve the yield and quality of forage crops.However,the suitable nitrogen application rate of silage corn/legume intercropping system in the arid area of Northwest China is not clear.Three planting methods of silage corn/Dolichos lablab intercropping(SL),silage corn/fodder soybean intercropping(SF),and silage corn monoculture(S)were conducted in this experiment.Four nitrogen application levels of 0 kg hm^(-2)(N1),120 kg hm^(-2)(N2),240 kg hm^(-2)(N3),and 360 kg hm^(-2)(N4)were set under each planting mode.To explore the suitable jade bean intercropping combination and nitrogen application rate in the arid area of Northwest China,the effects of planting methods and nitrogen application levels on forage crop yield,quality and water use were analyzed.The results showed that compared with S treatment,the hay yield of SL treatment increased significantly by 8.94%and 8.68%in 2019 and 2020,and the water use efficiency increased significantly by 12.28%and 8.90%,respectively.Compared with monoculture,intercropping significantly increased the contents of crude protein and crude ash,and significantly reduced the contents of starch and neutral detergent fiber.Compared with no nitrogen application,nitrogen application significantly increased hay yield,crude protein,starch,and crude fat content,significantly reduced neutral and acid detergent fiber content,but there was no significant effect on crude ash content.Compared with N1,the hay yields of N2,N3,and N4 increased significantly by 30.30%,56.19%,and 53.95%in 2019 and 22.02%,60.54%,and 51.83%in 2020,respectively.WUE of N3 and N4 was significantly higher than that of N1 and N2,but there was no significant difference between N3 and N4.Among all treatments,SL-N3 obtained the highest two-year average hay yield(33.10 t hm^(-2)),crude protein content(10.01%),and WUE(62.50 kg hm^(-2)mm^(–1)).To sum up,SL-N3 is a management model suitable for silage corn production in arid areas of northwest China.