During the past 50 years, desertification control researches in our country have made remarkable achievements. It is observed that the process of the desertification is gradual varied. It is possible to control the desertification and recover the vegetation under the condition of controlling the improper human activities. In the recent researches, there are many studies on the physical property and the nutrient contents of soil during the reversal process of the desertification.  

Based on field investigation and laboratory analysis, scientists from Cold and Arid Regions Environmental and Engineering Research Institute (CAREERI) analyzed the statistics and found the relation between the particulate nutrient content and nutrient content in bulk soil during the reversal of desertification in the multiple-years enclosed area to facilitate vegetation regeneration in Yanchi County, Ningxia Hui Autonomous Region. 

The experimental results showed that there was a gradual increase trend of the contents of soil organic carbon (SOC), nitrogen (N), phosphorus (P) and potassium (K) in each particle fraction and of SOC, N, P and K in bulk soil with the reduction of desertification degree.  

Correlation analysis revealed there was a significant positive correlation between the particulate soil nutrient contents in all the particle fractions and the soil nutrient contents in bulk soil.  

The enrichment of SOC, N, P and K contents in topsoil was a result jointly affected by both the fixation and storage of nutrients in bulk soil and the integration of nutrients in soil with different grains sizes during the reversal of desertification.  

Path analysis showed that the effects and importance of nutrients in soil with different grains sizes to nutrients in bulk soil were different, and the effects of unprotected particulate nutrients in very fine sand and moderate-coarse sand to nutrients in bulk soil was significant. 

This program is financially supported by the National Natural Science Foundation of China (No. 41201560, 51169001), National Key Technology R&D Program. The paper has been published on the Journal of Arid Zone Research, Vol. 30, No. 6, Nov. 2013.