弃耕地植被恢复过程中土壤酶活性与理化特性演变趋势研究

Evolution of soil enzyme activities and physical﹠chemical characteristics during vegetation restoration on abandoned cropland

【目的】研究黄土丘陵沟壑区不同弃耕年限草地土壤酶活性的特征与演变趋势,为正确评价土壤质量提供科学依据。【方法】在陕西安塞县纸坊沟流域,采集不同年限（1,2,3,4,5,6,7,8,9,13,15,20,25,30年）弃耕地0-20,20-40和40-60 cm土层土样,测定土壤理化性质及脲酶、蔗糖酶和碱性磷酸酶活性。【结果】随着弃耕时间的延长,土壤容重、pH值、有机质、CEC、全N、有效N等理化特性得到不同程度的改善,土壤脲酶、蔗糖酶与碱性磷酸酶活性均逐渐增强,土壤脲酶活性随土层深度的增加而大幅度递减;相关性分析表明,以上3种酶活性与土壤有机质、CEC、全N等理化性质显著正相关,与土壤pH等呈显著负相关,而3种酶之间的相关性也达极显著水平。【结论】在植被恢复过程中,脲酶、蔗糖酶与碱性磷酸酶活性逐步增强,土壤酶活性与植被的恢复是一个互动过程。

[Objective] The characteristics and evolution of soil enzymes under different abandoned years in loess hilly region were studied to provide scientific instructions to evaluate the soil quality, [Method] In Zhifanggou watershed of Ansai,Shaanxi,soil samples of 0--20,20--40 and 40--60 cm obtained from different years（1,2,3,4,5,6,7,8,9,13,15,20,25 or 30 years）abandoned cropland were taken to test the physical ＆ chemical characteristics,contents of urease, phosphatases and ucrase. [Result] During vegetation restoration, soil bulk density, organic matter content, CEC, total N, etc. were improving, urease, phosphatases and ucrase were increasing;urease activity in surface soil was far higher than in deep layer;soil enzymes were correlated with soil organic matter content,CEC, total N and pH,ete, moreover urease,phosphatases and ucrase were correlated with each other, [Conclusion] Soil urease,phosphatases and ucrase activities were increased during vegetation restoration, which showed soil enzyme activities and vegetation restoration were a mutual promoting process.