沙漠化逆转过程中不同粒组颗粒养分与全土养分的关系

通过野外采样和实验室分析，利用空间变化代替时间变化的手段，研究了宁夏盐池县多年围封区沙漠化逆转过程中不同粒组颗粒养分与全土养分的关系。结果表明：随着沙漠化程度的减小，中粗砂、极细砂和黏粉粒组分中有机碳和氮、磷、钾的含量及全土中有机碳和氮、磷、钾的含量均呈逐渐增大的趋势；相关分析表明，不同粒组颗粒养分与全土养分呈极显著正相关，沙漠化逆转过程中全土有机碳和氮、磷、钾养分的固存效应是与不同粒径颗粒结合的有机碳和氮、磷、钾养分共同作用的结果。通径分析表明，不同粒组颗粒养分对全土中各养分指标的影响程度和重要性不同，与粒径较大的中粗砂和极细砂结合的非保护性颗粒养分对全土养分的影响较显著。

Relationship between Particulate Nutrient Content and Nutrient Content in Bulk Soil during Reversal of Desertification

Based on field investigation and laboratory analysis, the values of particulate soil nutrient content and nutrient content in bulk soil were examined using the method of time space mutual substitution. The statistic analytical methods were used to analyze the relationship between the particulate soil nutrient content and nutrient content in bulk soil during the reversal of desertification in the multiple year enclosed area to facilitate vegetation regeneration in Yanchi County, Ningxia Hui Autonomous Region. The results showed that, with the reduction of desertification degree, there was a gradual increase trend of the contents of SOC, N, P and K in each particle fraction and of SOC, N, P and K in bulk soil. Correlation analysis revealed that 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.