氮磷钾肥对高寒草甸生物量及群落多样性指数的影响

Effects of N,P,K Fertilizers on Above-ground Biomass and Community Biodiversity of the Alpine Meadow

采用正交试验设计,添加氮、磷、钾肥不同组合,测定了高寒草甸生物量和群落多样性指数,分析施肥对高寒草甸群落结构的影响。结果表明,在氮肥、磷肥和钾肥分别为220、220和110kg/hm^2时(N3P5K3),莎草科牧草鲜重为337.72g/m^2,较对照处理显著增加了3.17倍(P<0.05)。施肥对莎草科牧草鲜重的影响要高于禾本科牧草和杂类草,施钾肥对莎草科牧草和杂类草生物量并无显著影响。氮肥对群落多样性指数H、E、P有显著影响,而磷钾肥则无显著影响。莎草科牧草鲜重与多样性指数呈显著负相关(P<0.05),氮肥、磷肥对莎草科牧草鲜重有显著正相关(P<0.05)。研究表明,氮磷钾肥在提高高寒草甸群落生物量的同时,也降低群落多样性指数。

The study tested above-ground biomass and community biodiversity of alpine meadow in different N,P and K fertilizing levels using orthogonal test in order to analyze the effect of fertilizers to alpine meadow plant community.The results showed the fresh weight of Cyperaceae was 337.72 g/m 2 when N,P and K fertilizers were 220,220 and 110 kg/hm 2(N3P5K3),significantly increased by 3.17 times than CK.Fertilizers were more important to Cyperaceae grasses than Gramineae and forbs.K fertilizer was not significantly important to Cyperaceae and forbs.N fertilizer had significant effects on H,E and P indexes instead of K fertilizer.Cyperaceae fresh weight had a negative correlation with community biodiversity indexes.N and P fertilizers were positively correlated with Cyperaceae fresh weight.These findings suggested NPK fertilizers significantly increased above-ground biomass and decreased plant community biodiversity simultaneously.