不同耕作措施下陇中黄土高原旱作农田土壤活性有机碳组分及其与酶活性间的关系

The relationship between soil labile organic carbon fractions and the enzyme activities under different tillage measures in the Loess Plateau of central Gansu province

通过设置在陇中黄土高原半干旱雨养农业区15年的不同保护性耕作措施长期定位试验,研究了传统耕作(T)、免耕(NT)、免耕结合秸秆覆盖(NTS)、传统耕作结合秸秆还田(TS)4种不同耕作措施下不同土层的土壤总有机碳、土壤活性有机碳、土壤微生物量、碳库管理指数和土壤蔗糖酶、淀粉酶、纤维素酶和过氧化物酶等4种参与碳循环土壤酶,并分析了土壤有机碳及其活性碳组分与土壤酶之间的相关关系。结果表明:0~30 cm土层,NTS处理可显著提高土壤有机碳、土壤活性有机碳、土壤微生物量碳及碳库管理指数,分别较T处理增加了16.3%、28.26%、41.88%、37.04%,NT、TS处理较T处理各指标也均有不同程度提高;在0~30 cm土层,NTS、TS、NT处理与T处理相比,蔗糖酶分别提高了33.84%、21.59%、25.15%,淀粉酶活性分别提高了20.90%、13.43%、12.69%,纤维素酶活性分别提高了39.13%、17.39%、4.34%,过氧化物酶活性分别提高了7.81%、2.08%、3.65%;土壤蔗糖酶、淀粉酶、纤维素酶、过氧化物酶与各形态有机碳及碳库管理指数均表现为显著或极显著正相关关系;蔗糖酶活性增加对有机碳积累作用最显著,有助于土壤总有机碳、活性有机碳、微生物量碳含量提高,土壤纤维素酶对土壤总有机碳和活性有机碳含量的增加有促进作用,过氧化物酶有利于总有机碳的积累。免耕结合秸秆覆盖是适宜该地区农田生态系统健康稳定发展,减少碳库损失的重要途径。

Based on long-term conservation tillage experiments at Dingxi in the rain-fed field of western Loess Plateau in Gansu province,we investigated the effects of four types of tillage methods,including conventional tillage（ T）,no tillage no stubble retention（ NT）,no tillage with stubble retention（ NTS） conventional tillage with stubble retention（ TS）,on soil organic carbon,soil labile organic carbon,soil microbial biomass carbon,carbon pool management and four kinds of soil enzymes involved in carbon cycling were invertase,diastase,cellulase and peroxidase. Aanalysis of the relationship between soil organic carbon and labile carbon fractions and soil enzymes showed that compared with T treatment NTS improved soil organic carbon,soil active organic carbon,soil microbial biomass carbon and carbon pool management index,by 16. 3%,28. 26%,41. 88%,37. 04%,respectively. Compared with T,NTS,TS,NT improved thesoil invertase,diastase,cellulase,peroxidase activities in 0 - 30 cm depth of soil,invertase activity were increased by33. 84%,21. 59%,25. 15%,diastase activity by 20. 90%,13. 43%,12. 69%,cellulase activity by 39. 13%,17. 39%,4. 34%,peroxidase activity by 7. 81%,2. 08%,3. 65%. Soil invertase,diastase,cellulase,peroxidase and labile organic carbon fractions and carbon pool management index were significantly positive correla-tion. With the increase in invertase activities,it was benefit to increase the concentration of total organic carbon,soil labile organic carbon and soil microbial biomass carbon,and the invertase played a vital role in the accumulating of soil organic carbon pool,soil cellulase has great effect on soil organic carbon and soil labile organic carbon. Peroxidase favourable for the accumulation of total organic carbon. No tillage with straw cover is suitable for the healthy and stable development of the farmland ecosystem in this region as an important way to reduce losses for carbon pool.