秸秆还田对棕壤酶活性的影响

Effects of straw returning on enzyme activity in brown soils

为实现秸秆循环利用,提升农田土壤肥力,选择辽宁地区典型棕壤实施秸秆不还田、秸秆粉碎还田、生物炭还田、牛粪还田、粉碎秸秆+生物炭混合还田、粉碎秸秆+牛粪混合还田、生物炭+牛粪混合还田,以探究在不同还田时长下这7种秸秆还田方式对棕壤酶活性的影响。结果表明:相较于还田2个月,还田18个月后的土壤脲酶、蔗糖酶活性显著增加,而土壤磷酸酶和过氧化氢酶活性分别显著降低了52%,72%。还田2个月后,相较于秸秆不还田,6种还田方式对土壤酶活性影响不显著,仅秸秆粉碎还田处理下土壤磷酸酶活性显著增加,约增加72%;而还田18个月后,秸秆粉碎还田处理对土壤蔗糖酶活性无显著影响,但脲酶、磷酸酶、过氧化氢酶活性分别显著增加94%,101%,23%。土壤酶活性与土壤理化性质的线性关系随还田时间的增加而增强。秸秆还田时间对土壤磷酸酶和过氧化氢酶活性的方差解释量最大,秸秆还田方式对蔗糖酶活性的方差解释量最大,二者交互作用对土壤脲酶活性的方差解释量最大。本研究结果表明,秸秆粉碎直接还田在激发棕壤酶活性和改良棕壤质量方面效果较为明显。

To achieve straw recycling and improve farmland soil fertility,typical brown soils in Liaoning Province were sampled to explore the effects of the straw returning methods on brown soil enzyme activities during different returning time by conducting no straw adding,crushed straw returning,biochar returning,cattle manure returning,straw+biochar mixed returning,straw+cattle manure mixed returning and biochar+cattle manure mixed returning.Compared to the 2-month-post-returning soils,soil urease and invertase activities increased significantly in the 18-month-post-returnning soils,while soil phosphatase and catalase activities significantly decreased by 52%and 72%,respectively.In the 2-month-post-returning soils,straw returning methods exerted no effects on soil enzyme activities relative to the no straw adding,and only crushed straw returning treatment significantly increased soil phosphatase activity approximately 72%.In the 18-month-post-returnning soils,crushed straw returning showed no significant effect on soil invertase but significantly increased soil urease,phosphatase and catalase activities by 94%,101%and 23%,respectively.The linear relationship between soil enzymes activities and soil properties became stronger over time.Straw returning time explained the largest part of the variance in soil phosphatase and catalase activities and straw return method explaining the largest part of the variance in soil invertase activities.Their joint effects explained the largest proportion of the variance in soil urease.Our results indicated that crushed straw returning had obvious effects in stimulating the enzyme activity of brown soils and improving the soil quality.