稻田冬闲期土壤酶活性及理化性质对不同施肥的响应

土壤酶在维持土壤生态系统功能中具有重要作用,探究土壤酶活性与土壤理化性质的关系可以更清晰地了解施肥后土壤环境的变化,对指导稻田的合理施肥具有重要意义。通过田间试验,以常规施肥为对照,设置3个施肥处理：常规施肥、施用控释肥料、有机无机配施,研究了不同施肥处理下冬闲期稻田3种土壤酶（蔗糖酶、脲酶、酸性磷酸酶）活性的变化,利用经典统计学分析和冗余分析探究施用不同类型肥料下土壤酶活性的差异,及其与土壤理化性质之间的关系。经典统计学分析表明不同试验地的不同施肥处理水稻产量、土壤理化性质和土壤酶活性均具有显著性差异。整体而言,ACRF（施用控释肥料）处理和NPKM（有机无机配施）处理水稻产量均高于CF（常规施肥）处理,增产效果在2.0%~7.3%之间;NPKM处理的耕层土壤理化性质得到较大程度改善;而3种酶活性表现为NPKM>CF、NPKM>ACRF。冗余分析表明7种理化性质在前两轴累计解释土壤酶活性的90.81%,即前两轴能够很好地反映土壤酶活性与土壤理化性质的关系。pH、SOC（土壤有机碳）与土壤酶活性呈极显著相关关系。土壤理化性质中SOC是土壤酶活性呈现差异性的关键因子,其次是pH。本试验条件下,施用控释肥料或者有机无机配施可较好地实现水稻增产和土壤质量提升。

Responses of Soil Enzyme Activities and Physicochemical Properties to Fertilization in Rice Field During Winter Fallow Period

Soil enzymes play an important role in maintaining the function of soil ecosystem. Exploring the relationship between soil enzyme activities and soil physicochemical properties can clarify the changes of soil environment after fertilization, which is of significance to guide the rational fertilization in rice field. An experiment with three treatments, conventional fertilization (the control), application of controlled release fertilizer (ACRF), and combined application of organic and inorganic fertilizer (NPKM), was conducted. The variations of different fertilizer applications in rice field during winter fallow period on three soil enzymes (sucrase, urease and acid phosphatase) activities were studied, using the classical statistical analysis and redundancy analysis to explore the difference of soil enzymes activities in different treatments and their relationships with soil physicochemical properties. The classical statistical analysis showed that there were significant differences of rice yield, soil physicochemical properties and soil enzyme activities among different treatments at the two experimental sites. Taken as a whole, the rice yield of ACRF and NPKM treatments were higher than that of CF treatment, and the range was between 2.0% and 7.3%. The physicochemical properties of soil under NPKM treatment were improved to a large extent. And the activities of three enzymes were NPKM > CF, NPKM > ACRF. Redundancy analysis indicated that the seven physicochemical properties explained 90.81% of the variations in soil enzyme activities in the first two axes, showing that the first two axes could well reflect the relationship between soil enzyme activities and soil physicochemical properties. And an extremely obvious relationship existed between pH, SOC (soil organic corban) and soil enzyme activities. In these soil physicochemical properties, SOC was a key factor causing the difference of soil enzyme activities, followed by pH. Under the condition of this experiment, the application of controlled-release fertilizer or the combined application of organic and inorganic fertilizer can better increase rice yield and soil quality.