紫色土区不同秸秆还田量对土壤酶活性的影响

Effects of different amounts of straw returning on soil enzyme activity in purple soil

为了探明长期秸秆不同还田量下紫色土区土壤酶活性及其主要驱动因子,以持续12年的四川紫色土长期定位试验为依托,设置:秸秆不还田(CK)、30%还田(RMW30)、50%还田(RMW50)和100%还田(RMW100)4个处理,测定了土壤各种酶活性以及土壤理化性质。结果显示,与CK处理比较,RMW100处理显著提高土壤有机质、碱解氮和速效钾含量以及pH。秸秆不同还田量处理均降低了β-纤维二糖苷酶(CBH)、纤维素酶(CL)、酚氧化酶(PhOx)和过氧化物酶(Perox)活性,提高了磷酸酶(Phos)、硫酸酯酶(Sul)、β-葡糖苷酶(βG)、α-葡糖苷酶(αG)、β-木糖苷酶(βX)、乙酰氨基葡萄糖苷酶(NAG)和亮氨酸氨基肽酶(LAP)活性。随着秸秆还田量的增加,β-纤维二糖苷酶(CBH)活性呈现降低趋势。冗余分析(RDA)显示土壤pH是土壤酶活性变化的主控因子,解释了方差变异的60.20%,达到显著水平。因此,紫色土区秸秆还田主要是通过土壤pH对土壤酶活性产生影响。秸秆100%还田增加了土壤肥力,提高了土壤pH,是提升紫色土区土壤质量最优的管理措施。

In order to find out the soil enzyme activity and its main driving factors in purple soil area under long-term straw returning,a 12-year long-term located experiment was conducted in purple soil in Sichuan.Four treatments were set up:without straw(CK),30%of straw returning(RMW30),50%of straw returning(RMW50)and 100%of straw returning(RMW100).The soil enzyme activities and soil physical and chemical properties were determined.The results showed that compared with CK treatment,RMW100 treatment significantly increased the contents of soil organic matter,alkali-hydrolyzable nitrogen,available potassium and pH.Different straw returning treatments decreased the activities ofβ-cellobisidase(CBH),cellulase(CL),phenoloxidase(PhOx)and peroxidase(Perox),and increased the activities of phosphatase(Phos),sulfase(Sul),β-glucosidase(βG),α-glucosidase(αG),β-xylosidase(βX),acetylglucosaminidase(NAG)and leucine aminopeptidase(LAP).With the increase of the amount of straw returning to the field,the activity ofβ-cellobisidase(CBH)decreased.Redundancy analysis(RDA)showed that soil pH was the main factor controlling the change of soil enzyme activity,explaining 60.20%of the variance variation,reaching a significant level.Therefore,the effect of straw returning on soil enzyme activity is mainly through soil pH in purple soil.100%of the straw returning increased soil fertility,improved the soil pH,which is the optimal management measures to improve the soil quality of the purple soil.