高山寒漠带3种垫状植物对土壤养分的影响

Effects of three cushion plants on soil nutrient in alpine areas

在青藏高原北缘海拔4 000m以上高山寒漠带选择典型的垫状植被设置研究样地,在样地中分别选取直径大于40cm的囊种草(Thylacospermum caespitosum(Camb.)Schischk.)、垫状点地梅(Androsace tapete Max-im.)、钻叶风毛菊(Saussurea subulata C.B.Clarke)3种垫状植物为研究对象,在样地中随机选取无垫状植物生长的区域作为对照,分别测定了3种垫状植物覆盖下的土壤和对照区域土壤的速效氮、速效磷、速效钾、全氮、全磷和全钾的含量.结果表明:测定的6个指标在3种垫状植物和对照间均差异极显著(P<0.01)或显著(P<0.05);其中,土壤速效磷含量在垫状植物和对照间差异最为显著,3种垫状植物的土壤速效磷含量比对照提高了312.8%～479.6%;垫状植物对速效氮和速效钾含量的提高程度也较大,均比对照提高了1倍以上;与速效养分相比,3种垫状植物对其覆盖下土壤全氮、全磷和全钾含量的促进作用较小,但都极显著或显著高于对照;对于土壤养分的促进效应在3种垫状植物间无显著差异.

Cushion plants are one of the most common growth forms in alpine habitats above 4 000 m alt.,in this study,we evaluated the modifications on soil N,P and K contents by three cushion species（Thylacospermum caespitosum（Camb.） Schischk.,Androsace tapete Maxim.and Saussurea subulata C.B.Clarke） in alpine community located at northern margin of Tibetan Plateau.The results showed that cushion plants significantly improved soil N,P and K contents,the available phosphorus contents of soil beneath three cushions were 312.8%～479.6% higher than that of the soil where no cushion plant growing on it.Three cushions also greatly improved available nitrogen and available potassium contents,which were one time higher than those of open areas.Compared with available nutrients,total nitrogen,phosphorus and potassium were improved less by the cushions,but were all significantly higher than those of the open areas.The modifications on soil nutrients between three cushions had no significant differences.