长期保护性耕作对黄土高原旱作农田土壤碳含量及转化酶活性的影响  

Effects of Long-Term Conservation Tillage on Soil Carbon Content and Invertase Activity in Dry Farmland on the Loess Plateau

作　　者：董秀 张燕 MUNYAMPIRWA Tito 陶海宁 沈禹颖[1] DONG Xiu;ZHANG Yan;MUNYAMPIRWA Tito;TAO HaiNing;SHEN YuYing(College of Pastoral Agriculture Science and Technology,Lanzhou University/State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems/National Field Scientific Observation and Research Station of Grassland Agro-ecosystems in Qingyang,Gansu,Lanzhou 730020)

机构地区：[1]兰州大学草地农业科技学院/草种创新与草地农业生态系统全国重点实验室/甘肃庆阳草地农业生态系统国家野外科学观测研究站,兰州730020

出　　处：《中国农业科学》2023年第5期907-919,共13页Scientia Agricultura Sinica

基　　金：国家重点研发计划(2022YFD1300803);甘肃省青年科技基金计划(22JR5RA533);国家自然科学基金(31872416);中国博士后面上项目(2021M691369);中央高校基本科研业务费定向探索项目(lzujbky-2021-pd01);甘肃省重点人才项目(2019-2021)。

摘　　要：【目的】探究黄土高原旱作农田粮草轮作系统长期保护性耕作对土壤碳含量、碳转化酶活性的影响,为旱作农田土壤固碳和农业可持续发展提供科学依据。【方法】基于甘肃庆阳草地农业生态系统国家野外科学观测研究站开展的长期保护性耕作试验(开始于2001年),分析传统耕作(T)、免耕(NT)、传统耕作+秸秆覆盖(TS)、免耕+秸秆覆盖(NTS)对玉米-冬小麦-饲用大豆粮草轮作系统玉米收获季不同土层(0—5、5—10、10—20 cm)土壤有机碳(SOC)、微生物量碳(MBC)含量、β-葡萄糖苷酶(βG)、纤维二糖水解酶(CBH)、β-木糖苷酶(βX)活性的影响。【结果】(1)保护性耕作措施可显著增加SOC、MBC含量,其中0—5 cm土层提升效果最显著。与传统耕作相比,秸秆覆盖使SOC和MBC含量分别升高19.1%和39.9%,免耕使SOC和MBC含量分别升高15.1%和34.3%。(2)保护性耕作措施显著提高了土壤碳转化酶活性,表现为βG>CBH>βX活性,对保护性耕作措施最敏感的酶是CBH。相比传统耕作,秸秆覆盖使0—5和5—20 cm土层βG、CBH、βX活性分别增加20.3%、37.6%、41.1%和-7.6%、99.9%、3.5%;免耕使0—5和5—20 cm土层βG、CBH、βX活性分别增加12.5%、31.0%、26.1%和-21.1%、22.1%、-12.1%。结构方程结果表明,土壤碳转化酶活性的变化主要受粮草轮作系统内土壤全氮含量的影响。(3)秸秆覆盖可直接影响土壤碳的积累,也可通过改变土壤全氮含量而间接影响土壤碳转化酶活性;免耕措施未显著影响土壤环境,导致土壤碳含量及碳转化酶活性无显著变化。【结论】黄土高原旱作农田粮草轮作系统中,土壤碳的积累主要受到秸秆覆盖的直接效应,而碳转化酶活性主要通过对系统内土壤全氮的间接作用而变化,其中,免耕+秸秆覆盖是提高土壤碳含量和酶活性的最有效措施。β-葡萄糖苷酶是参与土壤碳转化的主要酶。【Objective】The effects of long-term conservation tillage on soil carbon and carbon invertase activity in forage-crop rotation system of dry farmland in the Loess Plateau were explored to provide the scientific basis for soil carbon sequestration and sustainable and healthy development of agriculture in dry farmland. 【Method】In this study, we aimed to investigate the effects of long-term traditional tillage(T), no-tillage(NT), traditional tillage+straw mulch(TS), and no-tillage+straw mulch(NTS) on soil organic carbon(SOC), microbial biomass carbon content(MBC), β-glycosidase(βG), cellobiohydrolase(CBH) and β-xylosidase enzymes(βX) in forage-crop rotation system at the National Field Scientific Observation and Research Station of the Grassland Agricultural Ecosystem in Qingyang, Gansu Province. Soils were collected from 0-5, 5-10 and 10-20 cm depths at the harvest of maize(Zea mays L.). 【Result】(1) Conservation tillage significantly increased the contents of SOC and MBC in soil, especially in 0-5 cm soil layer. Compared with conventional tillage, straw mulching increased SOC and MBC by 19.1% and 39.9%, respectively,and no-tillage increased SOC and MBC by 15.1% and 34.3%, respectively.(2) Conservation tillage significantly increased soil carbon invertase activity, the three enzyme activities showed: βG>CBH>βX, the sensitivity of conservation tillage measures showed: CBH>βX>βG. Compared with traditional tillage, the activities of βG, CBH and βX in 0-5 cm soil layer under straw mulching increased by 20.3%, 37.6% and 41.1%, respectively, and those under no-tillage increased by 12.5%, 31.0% and 26.1%,respectively. Straw mulching in 5-20 cm soil layer increased βG, CBH and βX by-7.6%, 99.9% and 3.5%, respectively, and no-tillage increased them by-21.1%, 22.1% and-12.1%, respectively. In addition, the structural equation results showed that soil carbon invertase activity was mainly affected by soil total nitrogen content in forage-crop rotation system.(3) Straw mulching could directly affect the ac

关 键 词：秸秆覆盖 免耕 土壤有机碳 土壤酶活性 微生物量碳 

分 类 号：S153.6[农业科学—土壤学]