氮肥对羊草重度退化草地植物群落的影响

Effects of Nitrogen Fertilizer on Plant Communities Characteristics in Severely Degraded Leymus chinensis Grassland

对呼伦贝尔草甸草原羊草群落重度退化草地进行施肥改良研究。结果表明,不同施肥处理均可以提高群落盖度、密度、高度和现存量,其中,施氮量为15 kg/hm2对改善羊草群落盖度、密度方面效果最好;施氮量为105 kg/hm2在改善草群高度方面作用明显。在群落现存量上,不同处理在施肥当年其群落现存量显著高于对照,且群落现存量随着施肥量增加而增加,以150 kg/hm2的施肥量效果最为显著;不同施肥量对建群种羊草种群相对生物量均有显著效应,105 kg/hm2在改善羊草种群相对生物量方面作用明显;利用Margarlef丰富度指数分析表明,施肥显著减少了物种数。由此可知,施肥可以促进羊草复壮与自我繁殖,使其个体数量增加、盖度提高,群落物种逐渐减少,使优势种变得更加突出。

The effects of improved fertilization on the enclosed severely degraded community in Hulunbeier meadow grassland were studied. The results showed that fertilization significantly increased the cover, density, height and standing crop of plant community. The optimal application of nitrogen and P2O5 was 150 kg / hm^2 and 15 kg / hm^2. The optimal matching proportion of nitrogen and phosphate was 1 / 3. Fertilization significantly increased the relative biomass of L.chinensis population and reduced the number of species. Fertilization promoted L.chinensis rejuvenation and self-reproduction, increased the number of individuals and the coverage. Fertilization made species decrease, with the dominant species becoming more prominent.Fertilization contributed to restore and improve grassland productivity.