封育对荒漠退化草地土壤主要养分的影响初探

A tentative study of influences of fencing on soil nutrients of degradation desert grassland

以新疆天山北坡荒漠草地为研究对象，通过对两年围栏内外的O～20cm土壤养分进行对比分析，探讨短期围栏封育对土壤的影响。结果表明，退化草地围栏后土壤有效磷含量降低；中度、重度退化草地土壤表层碱解氮含量降低，极度退化草地土壤碱解氮含量升高；中度、极度退化草地土壤有机质含量升高。由此可以看出，当地严酷的自然条件和草地退化程度的不同，使得短期围栏封育对土壤养分恢复的效果除有效磷变化一致降低外，有机质、碱解氮、速效钾变化不一致，差异不明显。因此，只有通过长期监测，才能对围栏封育的效果做出客观的评价。

The influence of short-term fencing on soil nutrients was discussed by comparatively analyzing the change of nutrients in the 0-20 cm soil layer inside and outside of fences at the degenerated desert grassland of Xinjiang. The results showed that the soil Olsen-P content was depressed inside fences. The topsoil available N contents of fenced moderate degraded and fenced severe degraded grassland were de- pressed~ while that of fenced extreme degraded grassland was increased. After fencing, soil organic matter content of moderate degraded and extreme degraded grassland were increased. It can be seen due to the lo- cal harsh natural conditions and levels of grassland degradation were different. The effect of short-term fences on restoration of soil nutrients except Olsen-P content was depressed consistently. The changes of the soil organic matter, available N and available K were not obvious. For that reason, only through long- term monitoring, the effect of fencing on soil nutrients will be evaluated objectively.