The Effect Of Desertification On Soil And Vegetation

Taking Yanchi County in Ningxia Hui Autonomous Region as the research object, the main causes of desertification and the changes of soil and vegetation in the past few years were analyzed by using the methods of biodiversity and multivariate statistic analysis in detail based on the investigation data on different types of sample plots. The results show that the main causes of desertification in Yanchi County are frangible ecological condition (rich erosive sandy soil materials, drought weather condition, strong wind in winter & early spring, thin plant covering) with global change (temperature increasing, rainfall reducing with seasonable drought) combined with un-rational human activities. Moreover, the situations of soil and vegetation improved obviously in recent years such as the nature water content, vegetation coverage, vegetation height, and biomass especially during 2002-2003. The biodiversity of grassland under the different desertification controlling measures (by converting cropland to forests, closing and fencing and discontinuing farming and letting go out of cultivation) have changed to various extents. It was the rainfall that had crucial influence upon the reversion of the vegetation. Two key causes why vegetation in Yanchi recovered rapidly were stated: firstly, the implementation of policy of reverting arable land to forest and rangeland since 2001 and forbidding graze in the whole county since November 1st, 2002 devoted to the desertification controls. Secondly, the distinct increase of rainfall especially in 2002 and 2003 contributed greatly to restoration of vegetation.