Xie Xue-Feng, Pu Li-Jie, Wang Qi-Qi, Zhu Ming, Wang Xiao-Han
School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China.
Key Laboratory of the Coastal Zone Exploitation and Protection of Ministry of Land and Resources, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China.
Huan Jing Ke Xue. 2018 Mar 8;39(3):1404-1412. doi: 10.13227/j.hjkx.201707223.
Land reclamation transforms a tidal flat from a marine ecosystem to terrestrial ecosystem, which significantly changes the soil ecosystem process, affecting the soil enzyme activities. Soil enzyme is involved in almost all soil biochemical processes. Clarifying the relationship between soil physicochemical properties and soil enzyme activities can reveal the changes of soil quality after reclamation and provide a theoretical basis for the scientific regulation of the soil ecosystem. In this study, a total of 72 soil samples were collected from a coastal reclamation area with different years of reclamation (0, 7, 32, 40, and 63 a) in Rudong County. The changes in soil physicochemical properties and enzyme activities within different reclamation years were analyzed by classical statistical analysis, and the relationship between soil enzyme activities and physicochemical properties was analyzed using a redundancy analysis. The results showed that longterm land reclamation had significant effects on soil physicochemical properties and enzyme activities. pH and electrical conductivity showed a decreasing trend after reclamation, while the content of soil organic carbon, total nitrogen, and total phosphorus showed a trend of "rapidly accumulate-gradually consume-accumulate again" with increasing years of reclamation. Compared with the bare flat area (0 a), amylase, dehydrogenase, and acid phosphatase activity initially increased and then decreased with increasing years of reclamation, while urease and alkaline phosphatase activities were characterized by an increase-decrease-increase trend. Meanwhile, the enzyme activities within different reclamation ages were basically higher in surface soil than deep layers. Redundancy analysis revealed that the soil physicochemical properties explained 69.8% of the variation in soil enzyme activities, and an obvious relationship existed between pH, electronic conductivity, soil organic carbon, total nitrogen, total phosphorus, and soil enzyme activities (<0.01). The order of importance of soil physicochemical properties to soil enzyme activities was as follows:total nitrogen > soil organic carbon > pH > total phosphorus > electronic conductivity.
土地开垦将潮滩从海洋生态系统转变为陆地生态系统，这显著改变了土壤生态系统过程，影响土壤酶活性。土壤酶几乎参与了所有的土壤生化过程。阐明土壤理化性质与土壤酶活性之间的关系，可以揭示开垦后土壤质量的变化，并为土壤生态系统的科学调控提供理论依据。本研究从如东县一个具有不同开垦年限（0、7、32、40和63年）的沿海开垦区共采集了72个土壤样本。通过经典统计分析方法分析了不同开垦年限内土壤理化性质和酶活性的变化，并利用冗余分析方法分析了土壤酶活性与理化性质之间的关系。结果表明，长期土地开垦对土壤理化性质和酶活性有显著影响。开垦后pH值和电导率呈下降趋势，而土壤有机碳、全氮和全磷含量随着开垦年限的增加呈现“快速积累-逐渐消耗-再次积累”的趋势。与光滩区（0年）相比，淀粉酶、脱氢酶和酸性磷酸酶活性随着开垦年限的增加先升高后降低，而脲酶和碱性磷酸酶活性则呈现升高-降低-升高的趋势。同时，不同开垦年限的土壤酶活性在表层土壤中基本高于深层土壤。冗余分析表明，土壤理化性质解释了土壤酶活性69.8%的变异，且pH值、电导率、土壤有机碳、全氮、全磷与土壤酶活性之间存在显著关系（<0.01）。土壤理化性质对土壤酶活性的重要性排序为：全氮>土壤有机碳>pH值>全磷>电导率。
