坡耕地等高反坡阶整地措施对滇中典型流域土壤酸碱性和酶活性的影响

Effects of Site Preparation Contour Reverse-Slope Terrace on Soil Acidity-Alkalinity and Enzyme Activities in Typical Watershed of Central Yunnan

【目的】探讨等高反坡阶整地措施对坡耕地酸化土壤改良效果及酶活性的影响。【方法】以滇中迤者流域试验区已实施等高反坡阶的坡耕地土壤为研究对象(原状坡耕地为对照),采用野外调查采样、室内实验及经典统计分析的方法,研究试验样地土壤pH、交换性阳离子(Ca^(2+)、Mg^(2+)、K^(+)、Na^(+)、H^(+)、Al^(3+)、Fe^(3+))、阳离子交换量(CEC)及蔗糖酶、脲酶、磷酸酶、过氧化氢酶、蛋白酶、多酚氧化酶、淀粉酶指标的变化规律,以探究土壤酸化及酶活性变化特征。【结果】坡耕地等高反坡阶措施可显著降低致酸阳离子(H^(+)、Al^(3+)、Fe^(3+))含量(P<0.05),使得交换性H+降低20.00%,交换性Al^(3+)和交换性Fe^(3+)含量分别减少25.64%和69.29%。提升土壤pH 9.46%~13.25%、增加交换性盐基离子(Ca^(2+)、Mg^(2+)、K^(+)、Na^(+))11.14%~39.31%、3.59%~8.96%、7.89%~17.14%、3.35%~7.99%及CEC含量(P<0.05)14.74%~21.33%。实施措施后土壤脲酶、蔗糖酶、蛋白酶、过氧化氢酶和微生物量碳、氮的活性显著提高(P<0.05)6.43%~15.28%、7.00%~31.70%、38.56%~73.71%、8.01%~21.20%、7.08%~11.14%和17.57%~31.48%,磷酸酶活性较原状坡耕地显著(P<0.05)下降38.00%~95.85%,且pH、交换性盐基离子和CEC含量均与酶活性呈极显著正相关(P<0.01),而致酸阳离子与酶活性呈极显著负相关(P<0.01)。双因素方差分析表明,整地措施、酸化影响指标(pH、交换性离子)及其二者交互作用显著影响着酶活性(P<0.05),酸化影响指标对酶活性的贡献最大。【结论】布设等高反坡阶措施能改善土壤酸化环境,增强酶活性,这对于解决坡耕地土壤酸化问题,提高山区坡耕地生产力具有重要意义。

【Objective】This study is aimed to explore the effects of site preparation treatment contour reverse-slope terrace on the improvement and enzyme activities of acidified soil in slope farmland.【Method】The slope farmland soil in Yizhe River Basin with contour reverse-slope terrace treatment in central Yunnan was selected as a research area in this study(the original slope farmland without any treatment was selected as control).Following field investigation and sampling,the soil pH,exchangeable cations(Ca^(2+),Mg^(2+),K^(+),Na^(+),H^(+),Al^(3+)and Fe^(3+)),cation exchange capacity(CEC),sucrase,urease,phosphatase,catalase,protease,polyphenol oxidase and amylase were measured and statistically analyzed,to explore the characteristics of soil acidification and enzyme activity changes.【Result】The results showed that contour reverse-slope terrace treatment in slope farmland significantly reduced the contents of acidogenic cations(H^(+),Al^(3+),Fe^(3+))(P<0.05),with exchangeable H^(+) decreased by 20.00%,exchangeable Al^(3+)and exchangeable Fe^(3+)decreased by 25.64%and 69.29%,respectively.On the contrary,when compared with control,the soil pH of slop farmland implemented with contour reverse-slope terrace was increased by 9.46%~13.25%,the exchangeable base ions contents of Ca^(2+),Mg^(2+),K^(+)and Na^(+)were increased by 11.14%-39.31%,3.59%-8.96%,7.89%-17.14%,and 3.35%-7.99%,respectively,and CEC were increased by 14.74%-21.33%(P<0.05).After the implementation of the treatments,the activities of soil urease,sucrose,protease,catalase,polyphenol oxidase and microbial biomass carbon and nitrogen were significantly increased by 6.43%-15.28%,7.00%-31.70%,38.56%-73.71%,8.01%-21.20%,7.08%-11.14%and 17.57%-31.48%(P<0.05),respectively,while phosphatase activity was decreased significantly(P<0.05)by 38.00%-95.85%compared with that of untreated slope farmland.The pH,exchangeable base ions and CEC contents were significantly and positively correlated with enzyme activities(P<0.01),while acidogenic cations were significantly and negatively correlated with enzyme activities(P<0.01).Two-way analysis of variance showed that the site preparation measures,acidification indicators(pH,exchangeable ions)and their interaction significantly influenced enzyme activities(P<0.05),and acidification indicators had the greatest contribution to enzyme activities.【Conclusion】The site preparation treatment contour reverse-slope terrace alleviated the soil acidification environment and enhanced the enzyme activity,which is of great significance for solving the soil acidification problem of slope farmland and improving the productivity of slope farmland in mountainous areas.