刈割和养分回添对羊草草原植物群落生物量及其构成的影响

基于2011年开始的养分回添控制试验,研究锡林郭勒盟草原羊草+克氏针茅+糙隐子草群落在不同肥料(氮、植物割取部分和有机质)对羊草割草场植物群落地上生物量的影响。结果表明:与不刈割相比,刈割+有机质回添、刈割+植物回添和刈割处理显著降低了植物群落地上生物量,但刈割+N素回添处理生物量并没有显著降低。4种处理均增加杂类草和一、二年生植物的地上生物量。与单纯刈割相比,刈割+植物回添处理可增加根茎禾草生物量;刈割+N素回添处理显著增加丛生型禾草地上生物量。与单纯刈割相比,刈割+植物回添处理增加了羊草(Leymus chinensis)种群地上生物量,刈割+N素回添处理增加克氏针茅(Stipa krylovii)种群地上生物量并显著增加糙隐子草(Cleistogenes squarrosa)生物量。这说明养分回添对植物群落地上生物量的影响,不仅与所施肥料种类和施肥量有关,还与该草原植物群落物种组成有关。

The Effect of Mowing and Nutrient Adding Back on the Biomass and Compositions of Leymus Chinensis Grassland Plant Community

Based on the control test of nutrient adding back starting in 2011,the effect of different fertilizers (nitrogen,mowing parts of plants and organic matters) on the above-ground biomass of Leymus chinensis plus Stipa krylovii plus Cleistogenes squarrosa communities of XilinGol League mowing grassland was studied.The result showed:compared with the no-mowing,the mowing plus organic matter adding back,mowing plus plant adding back and mowing treatment significantly reduced the above-ground biomass of plant community,but mowing plus N element adding back showed no obvious reduction in biomass.The above-ground biomass of broad-leaved herbs and annuals and biennials all increased in four treatments.Compared with mowing only,mowing plus plant adding back increased the biomass of rhizomatous grasses and the above-ground biomass of Leymus chinensis community,and mowing plus N element adding back showed an obvious increase in the above-ground biomass of bunch-type grasses and Stipa krylovii and the biomass of Cleistogenes squarrosa,which indicated the effect of nutrient adding back on the above-ground biomass of plant community was not only associated with types and amount of fertilizers,but also related to the species composition of the grassland plant community.