土壤酶活性对沙地樟子松人工林衰退的响应

Response of soil enzyme activity to the decline of Pinus sylvestris var. mongolica plantations on sand land

采用时空互代法对辽宁省章古台地区10—60 a林龄的典型沙地樟子松人工林标准地土壤酶活性进行了测定,分析了土壤酶活性在时间(不同林龄)、空间(不同土层深度)的变化规律,及养分指标与土壤酶活性的关系,为分析樟子松人工林土壤退化问题及本研究区域土壤酶的后续研究提供参考.结果表明,该区域樟子松人工林土壤蔗糖酶和蛋白酶活性随林分年龄的增长而增高;土壤磷酸酶和过氧化氢酶活性先增高后降低趋势,在30 a林龄时分别达到最高值;土壤脲酶活性随林分年龄的增长呈先降低,30 a后保持稳定的趋势.5种土壤酶活性均随土层的加深而降低,且表层土壤酶活性显著高于20 cm以下土层土壤酶活性.随林龄和土层的递增,土壤酶指数与理化指标的变化趋势相似,说明土壤理化性状对土壤酶活性高低起重要作用.相关性分析表明,各土壤酶活性与养分因子间呈极显著相关,可用其表征林地土壤肥力状况.综上所述,可以从改善林地土壤理化性状入手,减缓樟子松人工林的提前衰退,而评价该区域林地土壤综合质量可采用测取土壤酶活性的方法.

Soil enzyme activities of typical Pinus sylvestris var. mongolica plantations aged 10—60 years in Zhanggutai of Liaoning Province were determined using time-space substitution method.The changes of soil enzyme activities with time( different ages) and location( different depths of soil layers),and the relationships between nutrients and soil enzyme activity were analyzed. The purpose was to study soil degradation of Pinus sylvestris var. mongolica plantations and provide reference for the future study of soil enzyme in the study area. The results showed that the activities of sucrase and protease in the Pinus sylvestris var. mongolica plantations increased with the increase of stand age.The activities of phosphatase and catalase increased at first and then decreased,and reached the highest respectively at the age of 30 years. The soil urease activity increased,and then decreasedwith the increase of stand age,and remained unchanged at the age of 30 years. The activities of five soil enzymes decreased with the deepening of soil layers,and the surface soil enzyme activity was significantly higher than soil enzyme activity below 20 cm soil layer. With the increase of stand age and soil layer,the change of soil enzyme and physicochemical was similar,indicating that soil physical and chemical properties played an important role in soil enzyme activity. The correlation analysis showed that there was a significant correlation between soil enzyme activities and nutrients,which can be used to characterize soil fertility in forest lands. In summary,the physicochemical properties of forest soil can be improved to reduce the early decline of Pinus sylvestris var. mongolica plantations,and the method of measuring soil enzyme activity can be used to evaluate the comprehensive quality of forest soil in the region.