长期免耕和秸秆覆盖量对黑土碳氮含量及碳氮循环相关酶活性的影响  

Effects of long-term no-tillage and different stover mulching amounts on soil carbon and nitrogen contents and enzyme activities of carbon and nitrogen cycle in Mollisols

作　　者：于洋 张常仁 杨雅丽 徐欣 吕付泽 郑甜甜[1,4] 解宏图 鲍雪莲[1,4] YU Yang;ZHANG Changren;YANG Yali;XU Xin;LYU Fuze;ZHENG Tiantian;XIE Hongtu;BAO Xuelian(Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110016,China;School of Geographical Science,Liaoning Normal University,Dalian 116029,Liaoning,China;University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Conservation Tillage and Ecological Agriculture,Liaoning Province,Shenyang 110016,China)

机构地区：[1]中国科学院沈阳应用生态研究所,沈阳110016 [2]中国科学院大学,辽宁大连116029 [3]辽宁师范大学地理科学学院,北京100049 [4]辽宁省现代保护性耕作与生态农业重点实验室,沈阳110016

出　　处：《应用生态学报》2024年第3期695-704,共10页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(U22A20610,41977048);黑土地保护与利用科技创新工程专项(XDA28090100);辽宁省揭榜挂帅项目(2021JH1/10400039-2);沈阳市科学技术计划项目(22-317-2-06)资助。

摘　　要：为探究免耕条件下不同秸秆覆盖量对黑土碳氮含量及酶活性的影响,寻找既能满足土壤碳氮积累需求,又能使经济效益最大化的秸秆覆盖量,本研究依托始建于2007年的东北黑土区保护性耕作长期定位试验平台,于2020年5月春播前对传统耕作(对照,CT)、免耕+无秸秆覆盖(NT0)、免耕+33%秸秆覆盖(NT_(33))、免耕+67%秸秆覆盖(NT_(67))和免耕+100%秸秆覆盖(NT_(100))处理下土壤碳氮含量、土壤酶活性及经济效益进行分析。结果表明:1)与CT相比,NT0的土壤有机碳(SOC)和总氮(TN)含量没有显著变化,但提高了土壤有机质抗分解性,降低了可溶性有机氮(DON)和铵态氮等可利用养分含量。与NT0相比,免耕秸秆覆盖显著增加了0~10 cm土层SOC含量,且随着覆盖量的增加而增加,此外NT_(67)和NT_(100)还显著提高了SOC储量,有机质积累效果好。不同秸秆覆盖量对0~10 cm土层土壤氮的影响不同,NT_(33)显著提高了DON含量及其占TN的比例;NT_(67)显著提高了DON含量;NT_(100)显著提高了TN含量。2)与CT相比,NT0显著降低了0~10 cm土层过氧化物酶(POD)活性。与NT0相比,NT_(33)显著提高了0~10 cm土层β-葡萄糖苷酶(βG)、纤维二糖酶(CB)、β-N-乙酰氨基葡萄糖苷酶(NAG)、多酚氧化酶(PPO)和POD活性,NT_(67)仅提高了CB、NAG和POD活性,但二者均缓解了微生物养分氮限制;NT_(100)则显著提高了10~20 cm土层PPO活性。3)NT_(33)的秸秆碳转化效率显著高于NT_(100),其经济收益也最高。综上,免耕33%秸秆覆盖处理既能促进养分循环,提高秸秆利用效率,提升黑土质量,又能最大限度保证农民收入,是本试验条件下的最佳组合。To understand the effects of different stover mulching amounts in no-tillage on soil carbon and nitrogen contents and enzyme activities,finding a stover mulching amount which can meet the requirement of soil carbon and nitrogen accumulation while maximizing economic benefits,we conducted a long-term conservation tillage field experiment since 2007 in Mollisols area of Northeast China.We analyzed soil carbon and nitrogen contents,enzyme activities and economic benefits under conventional tillage(Control,CT),no-tillage without stover mulching(NT_(0)),no-tillage with 33%stover mulching(NT_(33)),no-tillage with 67%stover mulching(NT_(67)),and no-tillage with 100%stover mulching(NT_(100))before planting in May 2020.The results showed that compared with CT,NT_(0)did not affect soil organic carbon(SOC)and total nitrogen(TN)contents,but increased soil organic carbon recalcitrance and decreased the availability of dissolved organic nitrogen(DON)and ammonium nitrogen.Compared with NT_(0),no-tillage with stover mulching significantly increased SOC contents in 0-10 cm layer and increased with the amounts of stover.In addition,NT_(67)and NT_(100)significantly increased SOC stocks,facilitating the accumulation of soil organic matter.The effects of different stover mulching amounts on soil nitrogen content in 0-10 cm layer were different.Specifically,NT_(33)increased DON content and DON/TN,NT_(67)increased DON content,while NT_(100)increased TN content.Compared with CT,NT_(0)decreased peroxidase(POD)activity in 0-10 cm layer.Compared with NT_(0),NT_(33)increasedβ-glucosidase(βG),cellobiase(CB),1,4-β-N-acetylglucosaminidase(NAG),polyphenol oxidase(PPO)and POD activities,while NT_(67)only increased CB,NAG and POD activities in 0-10 cm soil layer,both alleviated microbial nutrient limitation.NT_(100)increased PPO activity in 10-20 cm layer.NT_(33)increased carbon conversion efficiency of stover compared with NT_(100),and had the highest economic benefit.In all,no-tillage with 33%stover mulching was the optimal strategy,which co

关 键 词：保护性耕作 秸秆覆盖量 土壤碳氮 土壤酶 

分 类 号：S153.6[农业科学—土壤学] S154.2[农业科学—农业基础科学]