【目的】探究不同经营模式下薄壳山核桃‘波尼’(Carya illinoensis ‘Pawnee’)与油用牡丹‘凤丹’(Paeonia ostii ‘Feng Dan’)林地土壤的理化性质及酶活性变化特征,分析季节变化对各模式经营种植下土壤性状的影响。【方法】分别以薄壳山核桃纯林模式(模式Ⅰ)、薄壳山核桃-油用牡丹复合模式(模式Ⅱ)、油用牡丹单植模式(模式Ⅲ)为研究对象,分析不同经营模式下土壤的理化性状及酶活性的季节变化特征,通过最小数据集法(MDS)计算土壤肥力综合质量指数(IFI),并对土壤肥力变化进行评价。【结果】在各模式下,林地表层土壤养分及酶活性高于深层;土壤含水量和容重随春、夏、秋季节变化而变化;土壤pH在秋季最低,春、夏两季差异不显著;夏季土壤过氧化氢酶活性高于春、秋季;土壤有机质、全氮、速效钾含量及土壤蔗糖酶、脲酶活性基本表现为随春、夏、秋季节变化逐渐升高。模式Ⅲ下土壤有效磷含量秋季高于春、夏两季;夏季土壤肥力综合质量指数最低,但以模式Ⅱ最高。【结论】林地土壤酶活性与理化性质间具有相关性;各季节下薄壳山核桃-油用牡丹复合模式(模式Ⅱ)土壤肥力均显著优于其余模式,且夏季土壤肥力显著低于其他季节;土壤肥力受容重、全氮、有效磷、速效钾含量及脲酶、蔗糖酶活性直接影响,其中蔗糖酶活性在季节土壤肥力综合质量评价中均较为敏感。

【Objective】The aim of the present study was to investigate the soil physical properties, chemical properties, and enzyme activities under different Carya illinoensis ‘Pawnee’ and Paeonia ostii ‘Feng Dan’ planting modes, as well as analyze the effects of different modes and seasons on soil characteristics.【Method】The treatments included single cultivation of C. illinoensis (mode Ⅰ), compound cultivation of C. illinoensis ‘Pawnee’-P. ostii ‘Feng Dan’ (mode Ⅱ), and single cultivation of P. ostii (mode Ⅲ). Seasonal variation of soil physical properties, chemical properties, and enzyme activities were measured under different modes, and the minimum date set method and soil integrated fertility index (IFI) were utilized to evaluate the changes of soil fertility.【Result】The nutrient and enzyme activity in the surface soil were higher than those in the deep soil. The soil moisture content and bulk density gradually varied with the seasons of spring, summer and autumn. There was no significant difference on soil pH between the spring and summer seasons, and the lowest soil pH was observed in autumn. The soil catalase activity in summer was higher than that in spring and autumn. The soil organic matter content, total nitrogen content, available potassium content, sucrase activity, and urease activity increased during the seasonal variation of spring, summer, and autumn. In mode Ⅲ, the soil available phosphorus content in autumn was higher than that in spring and summer. The seasonal variation of the soil IFI was the lowest in summer and highest in mode Ⅱ.【Conclusion】There is a correlation among soil physical properties, chemical properties and enzyme activities. The soil fertility of the compound cultivation of C. illinoensis ‘Pawnee’-P. ostii ‘Feng Dan’ (mode Ⅱ) is significantly higher than single cultivation of either species, and the soil fertility quality is lower in summer than in spring and autumn. The soil fertility quality is directly affected by bulk density, total nitrogen content, available potassium content, available phosphorus content, sucrase activity, and urease activity. Further, sucrase activity is more sensitive in evaluating the soil IFI in all seasons.