Abstract:

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.

Key words: Mowing, Nutrient adding back, Above-ground biomass, Leymus chinensis steppe

摘要：

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。

关键词: 刈割, 养分回添, 地上生物量, 羊草草原