开垦种草对高寒草甸土壤理化性质的影响

Effects of cultivation on soil properties in alpine meadow

对玛曲高寒草甸天然草地及开垦种草8年和20年草地土壤理化性质进行了比较研究。结果表明,土壤含水量天然草地显著高于开垦种草8年草地;土壤容重0～10cm土层天然草地显著高于开垦种草20年草地;0～60cm土层土壤有机碳含量天然草地显著高于开垦种草草地,比开垦种草草地高38.66%。土壤全氮、速效氮、全磷和速效磷含量天然草地显著高于开垦种草草地。土壤全氮、速效氮和全磷含量随开垦种草年限增加逐渐下降。各样地土壤全氮、速效氮与土壤有机碳呈显著正相关关系。

In this study we analyzed soil physical and chemical properties in the natural grassland and the cultivated oat （Arena sativa） grasslands of 8 （ Ⅰ ） and 20 （Ⅱ ） years in alpine meadow of Maqu. There were significant differences in soil water content, soil organic carbon （SOC）, total nitrogen, total phos- phorus, available nitrogen and available phosphorus between the natural and the cultivated grassland. The soil bulk density of the natural grassland was significantly higher than that of Ⅱ in the 0 to 10 cm soil layer. The SOC of the natural grassland was 38.66% higher than cultivated grassland in the soil layer from 0 to 60 cm. Total nitrogen, available nitrogen, total phosphorus and available phosphorus of the natural grassland were also significantly higher than those of two cultivated grasslands （P^0. 05）. The total nitrogen, total phosphorus and available nitrogen of cultivated oat grasslands were deereased with the cultivated years increasing. The soil organic carbon had a significant linear relationship with total nitrogen and available nitrogen in the natural and cultivated grasslands.