腾格里沙漠东南缘飞播区白沙蒿植被密度与土壤水分关系的研究

对腾格里沙漠东南缘飞机播种区不同密度白沙蒿(Artemisia sphaerocephala Krasch)人工草地的土壤水分和植物生长状况进行研究。结果表明,白沙蒿密度在5.1~9株·m^-2时,整个生长期土壤水分处于严重亏缺状态, 0~100 cm土层水分含量仅为0.55%~0.7%,白沙蒿死亡率高达55%~76.7%;密度在1.9株·m^-2时,其土壤水分含量在0.65%~1.01%,白沙蒿死亡率为21.1%;密度在1.25株·m^-2时,土壤水分在0.79%~1.48%,白沙蒿无一株死亡,且植株个体生长状况好于密度大样地,并有自繁育苗补偿,这表明研究区种植白沙蒿的适宜密度在1株·m^-2左右。裸露沙地0~100 cm土壤含水量为1.3%~2.48%。

A Study on Relationship between Vegetation Density and Soil Water Content ofArtemisia sphaerocephala Air-sown Grassland in South-eastern Edge of Tengger Desert, InnerMongolia, China

Relationships of soil water content and plant growth in Artemisia sphaerocephala air-sown grassland were studied in southeastern edge of Tengger desert. The results showed that when vegetation densities was 5.1~9 plant·m^-2, soil water contents were only 0.55%~0.70% in 0~100 cm layer severely insufficient to need and plant mortality rates were as high as 55%~76. 7%; When vegetation density was 1.9 plant·m^-2, soil water content were 0.65%~1.01% and plant mortality rate was 21.1%; However, when vegetation density was 1.25 plant·m^-2, soil water contents were 0.79%~1.48%, no plant died, individual plant was growing better than those in high density field, and self-multiplied seedlings were growing under this condition. Therefore, the optimal density of Artemisia sphaerocephala was about 1.0 plant·m^-2 in this area. The study also indicated that soil granule constituent and microbiotic soil-crust depth were affected by vegetation density greatly. Coarse sand con tents were respectively 37.0%, 25.8% and 16.3% in bare desert, middle vegetation density and high vegetation density, whereas the correspondent thick of crusts were 0, 1.1~1.2 and 1.4~1.7 cm. By contrast, soil water content was 1.3%~2.48% in bare desert.