生态修复对川西北沙化草地土壤有机质和氮素的影响

Influences of ecological restoration on soil organic matter and nitrogen in desertification grassland in the northwestern Sichuan

为了了解生态修复过程中沙化草地土壤有机质和氮素的变化特征,选取了未修复沙化草地和围栏种植红柳生态修复年限分别为2年、4年、6年、8年的沙化草地作为研究对象,研究了川西北不同生态修复年限沙化草地0-60cm土层土壤有机质和氮素变化特征。结果表明:随着生态修复年限的增加,植被盖度和高度显著提高,各土层土壤有机质、全氮、碱解氮含量均呈现增加特征,其中,0-20cm土层增加幅度较大,生态修复8年沙化草地土壤有机质、全氮和碱解氮含量分别比未修复沙化草地增加95.60%、100.00%和50.73%,均极显著高于未修复沙化草地;20-40cm和40-60cm土层土壤有机质、全氮、碱解氮含量增加幅度及显著性明显低于0-20cm土层。

Planting branchy tamarisk was considered as one of main measures of ecological restoration of desertification grassland in the Northwestern Sichuan. In order to reveal the soil organic matter and nitrogen variation characteristics of desertification grassland in process of ecological restoration in the Northwestern Sichuan,the desertification grasslands with ecological restoration age two years,four years,six years,eight years and untreated had been taken as research objects. The result showed that with the restoration age increases,the vegetation coverage and average height increased gradually. In process of ecological restoration of desertification grassland,the contents of soil organic matter,total nitrogen and available nitrogen were increased in each soil layers. In 0- 20 cm soil layer,the variations were the most obvious. The content of soil organic matter,total nitrogen and available nitrogen of desertification grassland increased by 95. 60%,100. 00% and 50. 73% respectively compared with untreated desertification grassland. In process of ecological restoration of desertification grassland,the increasing extent of soil organic matter,total nitrogen and available nitrogen content in 20- 40 cm and 40- 60 cm soil layer were less than that in 0- 20 cm soil layer.