密度对三种豆科牧草生产力和水分利用率的影响

研究播种密度对3种豆科牧草生产力和水分利用效率的影响,以探讨其在草地农业系统中的合理优化模式。结果表明:沙打旺(Astragelus adsurgens)在高密区第2年生产力最高(18321 kg·hm^-2),第3年开始下滑;苜蓿(Medicago sativa)在中、高密区生产力的增幅和增量差别不显著,以第3年最高(22563和22108kg·hm^-2);胡枝子(Lespedeza daurica)在中密区第3年最高(7856 kg·hm^-2);加大密度使沙打旺提早进入生长盛期,第2年即达到高生产力和较高水分利用效率;苜蓿以中密区(20~30株/m²)效果最好;达乌里胡枝子的生产力和水分利用率偏低,在黄土塬区草地农业中没有优势。

Effect of Planting Density on the Productivity and WUE of Three Legumes in Highland of Loess Plateau

The effect of planting density on three legumes’ productivity and WUE in highland of Loess Plateau was studied by field experiment.Astragelus adsurgens.of high planting density reached to its highest productivity(18321 kg·hm^-2) in the second year and then declined in the following year.The productivity of Medicago sativa.of both medium and high planting densities peaked(22563 kg·hm^-2 and 22108 kg·hm^-2,respectively)in the third year;no significant amplitude and increment between them were detected.The highest productivity(7856 kg·hm^-2) of Lespedeza daurica. appeared in the third year at the medium seeding density.The results show that increased planting density allowed A.adsurgens enter the blooming period earlier and achieve its higher productivity and WUE in the second year;the productivity and WUE of M.sativa’s were improved with increased planting density and the medium density was relatively better;L.davurica has no advantage in the agro-grassland system in highland of Loess Plateau due to its low productivity and WUE.