免耕和秸秆还田对我国土壤碳循环酶活性影响的荟萃分析

doi:10.3864/j.issn.0578-1752.2021.09.009

摘要/Abstract

摘要：

【目的】探讨免耕和秸秆还田措施对我国农田土壤碳循环酶活性的影响,为有机物质转化和土壤健康提升提供科学依据。【方法】通过文献搜集,获得了目标文献56篇,建立了翻耕清茬（CT,507组）、翻耕+秸秆还田（SR,305组）、免耕（NT,291组）和免耕+秸秆还田（NTS,122组）处理对土壤碳循环酶（转化酶、纤维素酶、β-葡萄糖苷酶和多酚氧化酶）活性影响的数据库。采用数据整合（Meta-analysis）和增强回归树（BRT）的分析方法,探讨不同管理措施下土壤碳循环酶活性的差异,并量化气候特征、土壤特性和种植制度等因子对其影响程度。【结果】与CT相比,SR（28.0%）、NT（13.7%）和NTS（23.2%）处理显著增加（P<0.05）了土壤碳循环酶活性;SR、NT和NTS处理显著促进了转化酶活性,增幅分别为25.3%、16.2%和22.5%;SR处理对纤维素酶活性的增幅为36.6%。对于低土壤有机碳（SOC<10 g·kg^-1）而言,SR、NT和NTS处理对转化酶活性增幅分别为26.7%、24.2%和37.9%。在碱性（pH>7.5）土壤中,SR和NTS处理下转化酶活性分别增加了22.3%和28.7%。对于不同黏粒含量的土壤而言,黏粒含量<20%的土壤中SR和NT处理下转化酶活性分别提高了21.5%和22.3%;黏粒含量为20%—30%的土壤中SR、NT和NTS处理下转化酶活性增幅分别为26.1%、16.1%和25.3%。干旱指数较大（2—3.5和>3.5）时,SR（29.1%和20.5%）、NT（13.4%和17.0%）和NTS（9.0%和36.9%）处理均显著提高了转化酶活性。对于轮作种植制度而言,SR和NTS处理促进了转化酶活性,增幅分别为24.0%和29.4%;而在连作种植制度下,SR处理下转化酶活性提高了29.4%。对于不同试验年限而言,NTS处理对转化酶活性的提高幅度表现为：长期（>10年;39.9%）>中期（5—10年;31.7%）>短期（<5年;17.6%）;短期和中期秸秆还田（SR）均显著增强了转化酶活性,增幅分别为22.0%和27.3%。免耕和秸秆还田对转化酶活性的交互作用在SOC含量低（<10 g·kg^-1）、pH呈碱性（>7.5）、黏粒含量低（<20%）、干旱指数高（>3.5）、轮作和持续年限长（>10年）的土壤中较小。BRT分析结果表明,黏粒含量和土壤pH是影响SR处理对转化酶活性提高的主要因素,而SOC含量和干旱指数是影响免耕措施（NT和NTS）提高转化酶活性的主要因素。【结论】在我国实施免耕和秸秆还田措施,尤其是在SOC和黏粒含量较低或干旱指数较高的地区,对于转化酶活性的提高具有重要意义。

关键词: 免耕, 秸秆还田, 碳循环酶, 转化酶, 荟萃分析, 增强回归树

Abstract:

【Objective】The objectives of this study were to assess the effects of no-tillage and straw returning on C-cycling enzyme activities in China, so as to provide some insights into organic matter transformation and soil health improvement. 【Method】Based on 56 peer-reviewed papers in China, the database related to soil C-cycling enzyme activities (i.e., invertase, cellulase, β-glucosidase and polyphenol oxidase) under conventional tillage (CT, 507 sets), conventional tillage + straw returning (SR, 305 sets), no-tillage (NT, 291 sets) and no-tillage + straw returning (NTS, 122 sets) were constructed. By using meta-analysis and boosted regression tree (BRT) model, the effects of tillage and residues management practices on the soil C-cycling enzyme activities, and quantified the relative contribution of some variables (i.e., climate, soil properties, planting systems and duration) regulating the invertase activities were analyzed. 【Result】Compared with CT, the overall C-cycling enzyme activities under SR, NT and NTS soils were enhanced by 28.0%, 13.7%, and 23.2%, respectively. Specifically, the invertase activity was increased by 25.3% in SR and 16.2% under NT and 22.5% under NTS relative to CT. In addition, the cellulase activity in SR soil was higher by 36.6% than that in CT soil. In the soils with lower organic carbon concentration (SOC<10 g·kg^-1), SR, NT and NTS enhanced invertase activity by 26.7%, 24.2% and 37.9%, respectively. In the soils with higher soil pH (>7.5), the invertase activity was higher by 22.3% under SR and 28.7% under NTS, respectively. Considering the soil texture, the invertase activity in soils with lower clay content (i.e., <20%) was increased by 21.5% under SR and 22.3% under NT. Instead, this invertase activity in soils with moderate clay content (20%-30%) under the SR, NT and NTS was higher by 26.1%, 16.1% and 25.3%, respectively, relative to CT. In the regions with higher aridity index (2-3.5 and >3.5), the enhanced invertase activity was observed in the SR (29.1% and 20.5%), NT (13.4% and 17.0%) and NTS (9.0% and 36.9%) treatments. The application of SR and NTS in the crop rotation systems enhanced invertase activity by 24.0% and 29.7%, respectively, relative to CT, whereas only SR practice in continuous cropping system enhanced the invertase activity by 29.4%. The improved invertase activity by NTS varied with experimental duration showing long-term duration (>10 years; 39.9%) > medium-term duration (5-10 years; 31.7%)>short-term duration (<5 years; 17.6%). Moreover, SR increased invertase activity by 22.0% in short-term duration and 27.3% in medium-term duration. The interaction of no-tillage and straw returning on the invertase activity was limited in the soils with lower SOC concentrations (<10 g·kg^-1), higher soil pH (>7.5), lower clay content (<20%), higher aridity index (>3.5), crop rotation system and longer duration (>10 years). The BRT model indicated that clay content and soil pH played the most important roles on the invertase activities in the SR incorporated soils, while SOC concentration and drought index dominated in the no-tillage soils (NT and NTS) in controlling invertase activities. 【Conclusion】The application of no-tillage and straw returning had great significance to enhance invertase activity, especially in soils with lower SOC concentrations, lower clay content and higher drought index.

Key words: no-tillage, straw returning, C-cycling enzyme, invertase, Meta-analysis, boosted regression tree

马立晓,李婧,邹智超,蔡岸冬,张爱平,李贵春,杜章留. 免耕和秸秆还田对我国土壤碳循环酶活性影响的荟萃分析[J]. 中国农业科学, 2021, 54(9): 1913-1925.

MA LiXiao,LI Jing,ZOU ZhiChao,CAI AnDong,ZHANG AiPing,LI GuiChun,DU ZhangLiu. Effects of No-Tillage and Straw Returning on Soil C-Cycling Enzyme Activities in China: Meta-Analysis[J]. Scientia Agricultura Sinica, 2021, 54(9): 1913-1925.

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参考文献 61

[1]	关松荫. 土壤酶及其研究方法. 北京: 农业出版社, 1986.
	GUAN S Y. Soil Enzyme and Its Research Methods. Beijing: Agriculture Press, 1986. (in Chinese)
[2]	ZHANG P, CHEN X L, WEI T, YANG Z, JIA Z K, YANG B P, HAN Q F, REN X L. Effects of straw incorporation on the soil nutrient contents, enzyme activities, and crop yield in a semiarid region of China. Soil and Tillage Research, 2016,160:65-72.
[3]	PIOTROWSKA-DłUGOSZ A. Significance of the enzymes associated with soil C and N transformation. Carbon and Nitrogen Cycling in Soil, 2020,140(1/2):399-437.
[4]	LI S, ZHANG S R, PU Y L, LI T, XU X X, JIA Y X, DENG O P, GONG G S. Dynamics of soil labile organic carbon fractions and C-cycle enzyme activities under straw mulch in Chengdu Plain. Soil and Tillage Research, 2016,155:289-297.
[5]	SCHINNER F, VON MERSI W. Xylanase-, CM-cellulase- and invertase activity in soil: An improved method. Soil Biology and Biochemistry, 1990,22(4):511-515.
[6]	边雪廉, 赵文磊, 岳中辉, 王慧一, 焦浩, 隋海霞. 土壤酶在农业生态系统碳、氮循环中的作用研究进展. 中国农学通报, 2016,32(4):171-178.
	BIAN X L, ZHAO W L, YUE Z H, WANG H Y, JIAO H, SUI H X. Research process of soil enzymes effect on carbon and nitrogen cycle in agricultural ecosystem. Chinese Agricultural Science Bulletin, 2016,32(4):171-178. (in Chinese)
[7]	WICKINGS K, GRANDY A S, REED S C, CLEVELAND C C. The origin of litter chemical complexity during decomposition. Ecology Letters, 2012,15(10):1180-1188.
[8]	CHEN H Q, LIANG Q, GONG Y S, KUZYAKOV Y, FAN M S, PLANTE A F. Reduced tillage and increased residue retention increase enzyme activity and carbon and nitrogen concentrations in soil particle size fractions in a long-term field experiment on Loess Plateau in China. Soil and Tillage Research, 2019,194:104296.
[9]	CHU H Y, LIN X G, FUJII T, MORIMOTO S, YAGI K, HU J L, ZHANG J B. Soil microbial biomass, dehydrogenase activity, bacterial community structure in response to long-term fertilizer management. Soil Biology and Biochemistry, 2007,39:2971-2976.
[10]	孙建, 刘苗, 李立军, 刘景辉, 张星杰. 免耕与留茬对土壤微生物量C、N及酶活性的影响. 生态学报, 2009,29(10):5508-5515.
	SUN J, LIU M, LI L J, LIU J H, ZHANG X J. Influence of non-tillage and stubble on soil microbial biomass and enzyme activities in rain-fed field of Inner Mongolia. Acta Ecologica Sinica, 2009,29(10):5508-5515. (in Chinese)
[11]	STEINWEG J M, DUKES J S, WALLENSTEIN M D. Modeling the effects of temperature and moisture on soil enzyme activity: Linking laboratory assays to continuous field data. Soil Biology and Biochemistry, 2012,55:85-92.
[12]	赵亚丽, 郭海斌, 薛志伟, 穆心愿, 李潮海. 耕作方式与秸秆还田对土壤微生物数量、酶活性及作物产量的影响. 应用生态学报, 2015,26(6):1785-1792.
	ZHAO Y L, GUO H B, XUE Z W, MU X Y, LI C H. Effects of tillage and straw returning on microorganism quantity, enzyme activities in soils and grain yield. Chinese Journal of Applied Ecology, 2015,26(6):1785-1792. (in Chinese)
[13]	成艳红, 黄欠如, 武琳, 黄尚书, 钟义军, 孙永明, 张昆, 章新亮. 稻草覆盖和香根草篱对红壤坡耕地土壤酶活性和微生物群落结构的影响. 中国农业科学, 2017,50(23):4602-4612.
	CHENG Y H, HUANG Q R, WU L, HUANG S S, ZHONG Y J, SUN Y M, ZHANG K, ZHANG X L. Effects of straw mulching and vetiver grass hedgerows on soil enzyme activities and soil microbial community structure in red soil sloping land. Scientia Agricultura Sinica, 2017,50(23):4602-4612. (in Chinese)
[14]	ZHAO X, LIU S L, PU C, ZHANG X Q, XUE J F, REN Y X, ZHAO X L, CHEN F, LAL R, ZHANG H L. Crop yields under no-till farming in China: A meta-analysis. European Journal of Agronomy, 2017,84:67-75.
[15]	PITTELKOW C M, LIANG X Q, LINQUIST B A, VAN GROENIGEN K J, LEE J, LUNDY M E, VAN GESTEL N, SIX J, VENTEREA R T, VAN KESSEL C. Productivity limits and potentials of the principles of conservation agriculture. Nature, 2015,517:365-368.
[16]	DU Z L, ANGERS D A, REN T S, ZHANG Q Z, LI G C. The effect of no-till on organic C storage in Chinese soils should not be overemphasized: A meta-analysis. Agriculture, Ecosystems and Environment, 2017,236:1-11.
[17]	LIU C, LIU M, CUI J, LI B, FANG C M. Effects of straw carbon input on carbon dynamics in agricultural soils: A meta-analysis. Global Change Biology, 2014,20(5):1366-1381.
[18]	ZUBER S M, VILLAMIL M B. Meta-analysis approach to assess effect of tillage on microbial biomass and enzyme activities. Soil Biology and Biochemistry, 2016,97:176-187.
[19]	肖美佳, 张晴雯, 董月群, 刘杏认, 张爱平, 郑莉, 杨正礼. 免耕对土壤微生物量碳影响的Meta分析. 核农学报, 2019,33(4):833-839.
	XIAO M J, ZHANG Q W, DONG Y Q, LIU X R, ZHANG A P, ZHENG L, YANG Z L. Meta-analysis to assess impact of no-tillage on soil microbial biomass carbon. Journal of Nuclear Agricultural Sciences, 2019,33(4):833-839. (in Chinese)
[20]	LI Y Z, SONG D P, LIANG S H, DANG P F, SIDDIQUE K H M. Effect of no-tillage on soil bacterial and fungal community diversity: A meta-analysis. Soil and Tillage Research, 2020,204:104721.
[21]	LI Y, LI Z, CUI S, JAGADAMMA S, ZHANG Q P. Residue retention and minimum tillage improve physical environment of the soil in croplands: A global meta-analysis. Soil and Tillage Research, 2019,194:104292.
[22]	ROSENBERG M S, ADAMS D C, GUREVITCH J. MetaWin. Statistical Software for Meta-Analysis. Version 1. 2000.
[23]	GEISSELER D, SCOW K M. Long-term effects of mineral fertilizers on soil microorganisms - A review. Soil Biology and Biochemistry, 2014,75:54-63.
[24]	HEDGES L V, GUREVITCH J, CURTIS P S. The meta-analysis of response ratios in experimental ecology. Ecology, 1999,80(4):1150-1156.
[25]	WANG X Z, CURTIS P S, WANG X Z. A meta-analysis of elevated CO₂ effects on woody plant mass, form, and physiology. Oecologia, 1998,113(3):299-313.
[26]	LUO Y Q, HUI D F, ZHANG D Q. Elevated CO₂ stimulates net accumulations of carbon and nitrogen in land ecosystems: A meta-analysis. Ecology, 2006,87(1):53-63.
[27]	ELITH J, LEATHWICK J R, HASTIE T. A working guide to boosted regression trees. Journal of Animal Ecology, 2008,77(4):802-813.
[28]	LUO L, MENG H, GU J D. Microbial extracellular enzymes in biogeochemical cycling of ecosystems. Journal of Environmental Management, 2017,197:539-549.
[29]	BOWLES T M, ACOSTA-MARTINEZ V, CALDERON F, JACKSON L E. Soil enzyme activities, microbial communities, and carbon and nitrogen availability in organic agroecosystems across an intensively- managed agricultural landscape. Soil Biology and Biochemistry, 2014,68:252-262.
[30]	MANGALASSERY S, MOONEY S J, SPARKES D L, FRASER W T, SJOGERSTEN S. Impacts of zero tillage on soil enzyme activities, microbial characteristics and organic matter functional chemistry in temperate soils. European Journal of Soil Biology, 2015,68:9-17.
[31]	VILLAMIL M B, LITTLE J, NAFZIGER E D. Corn residue, tillage, and nitrogen rate effects on soil properties. Soil and Tillage Research, 2015,151:61-66.
[32]	李委涛, 李忠佩, 刘明, 江春玉, 吴萌, 陈晓芬. 秸秆还田对瘠薄红壤水稻土团聚体内酶活性及养分分布的影响. 中国农业科学, 2016,49(20):3886-3895.
	LI W T, LI Z P, LIU M, JIANG C Y, WU M, CHEN X F. Enzyme activities and soil nutrient status associated with different aggregate fractions of paddy soils fertilized with returning straw for 24 years. Scientia Agricultura Sinica, 2016,49(20):3886-3895. (in Chinese)
[33]	AKHTAE K, WANG W Y, KHAN A, REN G X, AFRIDI M Z, FENG Y Z, YANG G H. Wheat straw mulching with fertilizer nitrogen: An approach for improving soil water storage and maize crop productivity. Plant Soil and Environment, 2018,64(7):330-337.
[34]	徐国伟, 段骅, 王志琴, 刘立军, 杨建昌. 麦秸还田对土壤理化性质及酶活性的影响. 中国农业科学, 2009,42(3):934-942.
	XU G W, DUAN H, WANG Z Q, LIU L J, YANG J C. Effect of wheat-residue application on physical and chemical characters and enzymatic activities in soil. Scientia Agricultura Sinica, 2009,42(3):934-942. (in Chinese)
[35]	DAI J, HU J L, ZHU A N, BAI J F, WANG J H, LIN X G. No tillage enhances arbuscular mycorrhizal fungal population, glomalin-related soil protein content, and organic carbon accumulation in soil macroaggregates. Journal of Soils and Sediments, 2015,15(5):1055-1062.
[36]	李彤, 王梓廷, 刘露, 廖允成, 刘杨, 韩娟. 保护性耕作对西北旱区土壤微生物空间分布及土壤理化性质的影响. 中国农业科学, 2017,50(5):859-870.
	LI T, WANG Z T, LIU L, LIAO Y C, LIU Y, HAN J. Effect of conservation tillage practices on soil microbial spatial distribution and soil physico-chemical properties of the Northwest Dryland. Scientia Agricultura Sinica, 2017,50(5):859-870. (in Chinese)
[37]	PIAZZA G, PELLEGINO E, MOSCATELLI M C, ERCOLI L. Long-term conservation tillage and nitrogen fertilization effects on soil aggregate distribution, nutrient stocks and enzymatic activities in bulk soil and occluded microaggregates. Soil and Tillage Research, 2020,196:104482.
[38]	SIX J, FREY S D, THIET R K, BATTEN K M. Bacterial and fungal contributions to carbon sequestration in agroecosystems. Soil Science Society of America Journal, 2006,70:555-569.
[39]	任万军, 黄云, 吴锦秀, 刘代银, 杨文钰. 免耕与秸秆高留茬还田对抛秧稻田土壤酶活性的影响. 应用生态学报, 2011,22(11):2913-2918.
	REN W J, HUANG Y, WU J X, LIU D Y, YANG W Y. Effects of no-tillage and stubble-remaining on soil enzyme activities in broadcasting rice seedlings paddy field. Chinese Journal of Applied Ecology, 2011,22(11):2913-2918. (in Chinese)
[40]	TAYLOR J P, WILSON B, MILLS M S, BURNS R G. Comparison of microbial numbers and enzymatic activities in surface soils and subsoils using various techniques. Soil Biology and Biochemistry, 2002,34(3):387-401.
[41]	SIX J, FELLER C, DENEF K, OGLE S M, SA J C D, ALBRECHT A. Soil organic matter, biota and aggregation in temperate and tropical soils - Effects of no-tillage. Agronomie, 2002,22(7/8):755-775.
[42]	SIX J, BOSSUYT H, DEGRZE S, DENEF K. A history of research on the link between (micro) aggregates, soil biota, and soil organic matter dynamics. Soil and Tillage Research, 2004,79:7-31.
[43]	杜章留, 张庆忠, 任图生. 农田土壤碳饱和机制研究进展. 土壤与作物, 2015,4(2):49-56.
	DU Z L, ZHANG Q Z, REN T S. Advances of soil carbon saturation mechanisms in agroecosystems. Soil and Crop, 2015,4(2):49-56. (in Chinese)
[44]	HOOKER B A, MORRIS T F, PETERS R, CARDON Z G. Long-term effects of tillage and corn stalk return on soil carbon dynamics. Soil Science Society of America Journal, 2005,69(1):188-196.
[45]	ZHAO Y C, WANG M Y, HU S J, ZHANG X D, OUYANG Z, ZHANG G L, HUANG B, ZHAO S W, WU J S, XIE D T, ZHU B, YU D S, PAN X Z, XU S X, SHI X Z. Economics- and policy-driven organic carbon input enhancement dominates soil organic carbon accumulation in Chinese croplands. Proceeding of the National Academy of Sciences of the United States of America, 2018,115(16):4045-4050.
[46]	XU Z W, ZHANG T Y, WANG S Z, WANG Z C. Soil pH and C/N ratio determines spatial variations in soil microbial communities and enzymatic activities of the agricultural ecosystems in Northeast China: Jilin Province case. Applied Soil Ecology, 2020,155:103629.
[47]	MALTAIS-LANDRY G. Legumes have a greater effect on rhizosphere properties (pH, organic acids and enzyme activity) but a smaller impact on soil P compared to other cover crops. Plant and Soil, 394(1):139-154.
[48]	STURSOVA M, BALDRIAN P. Effects of soil properties and management on the activity of soil organic matter transforming enzymes and the quantification of soil-bound and free activity. Plant and Soil, 2011,338(1/2):99-110.
[49]	ZHANG X M, GUO J H, VOGT R D, MULDER J, WANG Y J, QIAN C, WANG J G, ZHANG X S. Soil acidification as an additional driver to organic carbon accumulation in major Chinese croplands. Geoderma, 2020,366:114234.
[50]	GIANFREDA L, RUGGERO P. Enzyme activities in soil//NANNIPIERI P, SMALLA K. Nucleic Acids and Proteins in Soil. Berlin: Springer, 2006: 257-311.
[51]	JIN K, SIEUTEL S, BUCHAN D, DE NEVE S, CAI D X, GABRIELS D, JIN J Y. Changes of soil enzyme activities under different tillage practices in the Chinese Loess Plateau. Soil and Tillage Research, 2009,104(1):115-120.
[52]	HENRY H A L. Soil extracellular enzyme dynamics in a changing climate. Soil Biology and Biochemistry, 2012,47:53-59.
[53]	ALSTER C J, GERMAN D P, LU Y, ALLISON S D. Microbial enzymatic responses to drought and to nitrogen addition in a southern California grassland. Soil Biology and Biochemistry, 2013,64:68-79.
[54]	ZHANG S L, ZHANG X Y, HTFFMAN T, LIU X B, YANG J Y. Influence of topography and land management on soil nutrients variability in Northeast China. Nutrient Cycling in Agroecosystems, 2011,89(3):427-438.
[55]	谷岩, 邱强, 王振民, 陈喜凤, 吴春胜. 连作大豆根际微生物群落结构及土壤酶活性. 中国农业科学, 2012,45(19):3955-3964.
	GU Y, QIU Q, WAN Z M, CHEN X F, WU C S. Effects of soybean continuous cropping on microbial and soil enzymes in soybean rhizosphere. Scientia Agricultura Sinica, 2012,45(19):3955-3964. (in Chinese)
[56]	YANG X L, GAO W S, ZHANG M, CHEN Y Q, SUI P. Reducing agricultural carbon footprint through diversified crop rotation systems in the North China Plain. Journal of Cleaner Production, 2014,76:131-139.
[57]	QIN S H, YEBOAH S, CAO L, ZHANG J L, SHI S L, LIU Y H. Breaking continuous potato cropping with legumes improves soil microbial communities, enzyme activities and tuber yield. PLoS ONE, 2017,12(5):e0175934.
[58]	牛倩云, 韩彦莎, 徐丽霞, 张艾英, 仪慧兰, 郭二虎. 作物轮作对谷田土壤理化性质及谷子根际土壤细菌群落的影响. 农业环境科学学报, 2018,37(12):2802-2809.
	NIU Q Y, HAN Y S, XU L X, ZHANG A Y, YI H L, GUO E H. Effects of crop rotation on soil physicochemical properties and bacterial community of foxtail millet rhizosphere soil. Journal of Agro-Environment Science, 2018,37(12):2802-2809. (in Chinese)
[59]	李玉洁, 王慧, 赵建宁, 皇甫超河, 杨殿林. 耕作方式对农田土壤理化因子和生物学特性的影响. 应用生态学报, 2015,26(3):939-948.
	LI Y J, WANG H, ZHAO J N, HUANGFU C H, YANG D L. Effects of tillage methods on soil physicochemical properties and biological characteristics in farmland. Chinese Journal of Applied Ecology, 2015,26(3):939-948. (in Chinese)
[60]	TABATABAI M A. Soil enzymes//BOTTOMLEY P S, ANGLE J S, WEAVER R W. Methods of Soil Analysis: Part 2-Microbiological and Biochemical Properties. Madison: Soil Science Society of America, 1994: 775-833.
[61]	SINSABAUGH R L, CARREIRO M M, REPERT DA. Allocation of extracellular enzymatic activity in relation to litter composition, N deposition, and mass loss. Biogeochemistry, 2002,60(1):1-24.

耕作方式 Tillage		土壤有机碳 SOC (g·kg^-1)	土壤pH Soil pH	黏粒 Clay (%)	干旱指数 Aridity index	种植制度 Cropping system	持续年限 Experimental duration (a)
秸秆还田 Straw returning, SR	平均值 Mean	14.7	7.7	26.7	2.69	—	6.39
	样本数 No.	305	305	305	305	275	290
	标准误 SE	0.42	0.03	0.42	0.05	—	0.45
	范围 Range	3.7—34.0	5.5—8.6	11.2—49.7	0.69—6.29	—	1—30
免耕 No-tillage, NT	平均值 Mean	11.1	7.8	23.3	4.22	—	4.95
	样本数 No.	291	291	289	291	230	256
	标准误 SE	0.31	0.04	0.28	0.24	—	0.28
	范围 Range	3.7—29.0	5.3—8.8	13.3—38.6	0.45—23.36	—	1—18
免耕+秸秆还田Both no-tillage and straw returning, NTS	平均值 Mean	11.7	7.8	24.5	3.10	—	4.50
	样本数 No.	122	122	122	122	120	102
	标准误 SE	0.46	0.07	0.43	0.10	—	0.42
	范围 Range	6.0—29.0	5.5—8.6	13.3—34.4	1.10—6.29	—	1—25

指标 Item	秸秆还田 SR	免耕 NT	免耕+秸秆还田 NTS
土壤有机碳 SOC (g·kg^-1)	P<0.01	P<0.01	P<0.05
土壤pH Soil pH	P<0.01	P<0.01	P<0.01
黏粒含量 Clay content (%)	P<0.01	P<0.01	P<0.05
干旱指数 Aridity index	P<0.01	P<0.01	P<0.01
种植制度 Cropping system	P<0.01	P<0.01	P<0.01
持续年限 Experimental duration (a)	P<0.01	P<0.01	P<0.01