退耕地养分和微生物量对土壤酶活性的影响

为了解侵蚀环境下植被恢复土壤酶活性对土壤养分和微生物量指标的响应规律,以典型侵蚀环境黄土丘陵区纸坊沟流域生态恢复1~50年撂荒地长期定位试验点为研究对象,采用典型逐步回归和非线性拟合来分析各指标间的耦合关系.结果表明,土壤酶活性除a淀粉酶外,均与土壤养分因子和微生物量指标有较高的相关性(P<0.05).在土壤酶活性和养分因子间,尿酶和纤维素酶主要受总氮影响,碱性磷酸酶、过氧化氢酶、蔗糖酶和多酚氧化酶主要受可利用氮影响,蔗糖酶和多酚氧化酶还受到有机质的影响;在土壤酶活性和微生物量指标间,尿酶主要受微生物量磷影响,碱性磷酸酶、过氧化氢酶、蔗糖酶和多酚氧化酶均受微生物量碳影响,纤维素酶则受微生物量氮影响,但多酚氧化酶与可利用氮、有机质和微生物量碳呈负相关;此外,它们之间均存在良好的对数关系(y=b+alnx, P<0.05).

Effects of soil nutrient and soil microbial biomass on soil enzyme activities in abandoned croplands with different restoration age

In order to make a better understanding on the effects of soil nutrient and soil microbial biomass on soil enzyme activities under erosion environment, long-term located farmland with an abandoned age sequences of 0, 1, 5, 7, 10, 15, 20, 25, 30, 40, and 50 years in Zhifanggou watershed (8.27km2 ), Shaanxi Province were studied, which was a typical erosion environment on loess hilly region. The coupling relationships among indexes of soil enzyme with soil nutrient and microbial biomass were analyzed by using stepwise and nonlinear regression. Soil enzyme activities had a significant correlation with soil fertilizer and soil microbial biomass except a-amylase (P<0.05). For soil enzyme activities and soil fertilizer factors, Urease (URE) and cellulase (CEL) were affected by total N, alkaline phosphatase (ALP) and catalase (CAT) were affected by available N, saccharase (SAC) and polyphenol oxidase (PPO) were affected by available N and organic matter. For soil enzyme activities and soil microbial biomass, Urease (URE) was affected by soil microbial biomass P; alkaline phosphatase (ALP), catalase (CAT), saccharase (SAC) and polyphenol oxidase (PPO) were affected by soil microbial biomass C, cellulase (CEL) was affected by soil microbial biomass N. However, polyphenol oxidase (PPO) decreased with the increase of available N, organic matter and soil microbial biomass C. There was a significant logarithmic relationship among those indexes (y=b+alnx, P<0.05).