土壤紧实度对羊草形态及其生物量的影响

摘要

随着农牧业的快速发展, 农业机械碾压和过度放牧践踏, 导致草地土壤紧实度增大.为掌握羊草对紧实土壤的适应状况, 用人工土柱研究了容重分别为1 400. 8、1 557、1 640、1 706. 3、1 797. 7 kg·m-3的土壤对羊草生长的影响.结果表明:随着土壤紧实度从1 557 kg·m-3增加至1 706. 3 kg·m-3, 羊草构件密度显著增加, 当土壤紧实度加重到1 797. 7 kg·m-3时, 构件密度显著降低.随着土壤紧实度的增加, 羊草通过增加叶密度和蘖密度, 提高光能利用率, 增加根茎生物量、根生物量、根冠比, 增加根茎生物量分配, 提高其土壤抵抗外力的能力.表明羊草通过改变形态塑性, 响应和适应紧实土壤.%With the rapid development of agriculture and animal husbandry, agricultural machinery crushed and overgrazing trampled, the soil compaction of grassland has been increased. In order to know the adaptation of Leymus chinensis to soil compaction, the effects of soil different bulk density 1 400. 8, 1 557, 1 640, 1 706. 3, 1 797. 7 kg·m-3on the growth of Leymus. chinensis were investigated by using soil columns. The results indicate that module density would be increased significantly with the increase of soil compactness from 1 557 kg·m-3to1 706. 3 kg·m-3, but decreased significantly to 1 797. 7 kg·m-3. The leaf density and tiller density would be increased, while the soil compaction is increasing to improve the utilization rate of solar energy. Rhizome biomass, root biomass and root shoot ratio would increase with the increasing soil compaction to improve rhizome biomass allocation. It reveals that Leymus. chinensis could respond to compact soil by changing its morphological plasticity.