施肥与切根对退化羊草草原土壤理化性质和酶活性的影响

从培肥草地土壤肥力的角度,研究了施肥(低氮、高氮、磷、低氮磷、高氮磷)和切根对退化羊草草原土壤理化性质、酶活性的影响,为评价监测研究区农业措施提供科学依据。结果表明:1)施肥和切根对草地土壤有机碳、全磷、C/N、电导率和pH无显著影响,切根处理使土壤全氮含量减少了14.5%。2)切根处理草地的土壤酶活性均高于施肥处理,且脲酶对农业措施的响应更敏感,变化范围为0.82~2.26 mg $NH_{4}^{+}$ ·g^-1·3 h^-1。3)土壤有机碳与全氮、C/N、铵态氮、硝态氮、速效氮之间存在正相关关系,与全磷、电导率、pH、土壤酶活性之间存在负相关关系。因此,施肥和切根可在短期内提高退化羊草草原土壤中的有效养分含量,切根有利于土壤酶活性的提高,从而对草地养分的转化产生潜在的促进作用。

Influence of fertilization and root cutting on soil physicochemical properties and enzyme activities in a degraded Leymus chinensis steppe

To improve the soil fertility of degraded Leymus chinensis steppe, influences of fertilization and root cutting on soil physicochemical properties and enzyme activities were studied. Key results were: 1) Soil organic carbon, total phosphorus, C/N, electrical conductivity and pH were not affected by fertilization and root cutting, but soil total nitrogen was reduced 14.5% by root cutting. 2) Grassland where root cutting was performed had higher soil enzymatic activity than fertilized grassland, and soil urease activity was responsive to agricultural practices, ranging from 0.82-2.26 mg $NH_{4}^{+}$ ·g^-1 ·3 h^-1. 3) Soil organic carbon level was positively correlated with soil total nitrogen, C∶N ratio, ammonium nitrogen, nitrate nitrogen and available nitrogen, but was negatively correlated with total phosphorus, electrical conductivity, pH and enzymatic activities. Hence, fertilization and root cutting improved soil available nutrients in degraded L. chinensis steppe, and root cutting provided an additional benefit of increased soil enzymatic activities, which may also contribute to the increase in soil nutrient transformation.