Effect of land consolidation history on soil quality of purple hilly region

In order to study the cumulative effect of land consolidation on soil quality of purple hilly region, field sampling and laboratory analysis were combined to explore the variation rule of soil quality on different slope positions with different land consolidation history (1, 3 and 5 a), based on the basic evaluation factors of soil physical-chemical and biological properties. The results showed that a trend of reducing first and increasing afterwards with increasing consolidation history could be found in the content of soil organic matter and available N on three types of slope position (2°-6°, ＞6°-15°, ＞15°-25°) within five years. The content of available P and K both decreased appreciably after the accomplishment of land consolidation for one year, and then, the former showed the trend of returning rapidly, while the latter showed no increase-back. Soil cation exchange capacity(CEC) increased after land consolidation, and the increase amplitude was between 19.44% and 24.04%. There was no notable regular change existing in biological properties of soil on different types of slope position within five years after land consolidation, only the activity of acid phosphatase was enhanced with increasing consolidation history, and the difference was significant (P＞0.05). One year after the accomplishment of land consolidation, the change of soil quality which was characterized by the physical-chemical and biological properties was the most uneven, but it was improved after the accomplishment of land consolidation for three and five years to a certain extent. Consequently, the situation of soil physical-chemical and biological properties can be promoted by the implementation of land consolidation in purple hilly region, and also the comprehensive quality of soil. This positive role to soil quality will be more and more obvious with the increasing land consolidation history.