秸秆还田模式对小麦-玉米轮作体系土壤有机碳固存的影响  

Effect of Straw Returning Mode on Soil Organic Carbon Sequestration

作　　者：赵惠丽 董金琎 师江澜[1] 徐苗 田霄鸿[1] ZHAO Huili;DONG Jinjin;SHI Jianglan;XU Miao;TIAN Xiaohong(College of Natural Resource and Environment,Northwest A&F University/Key Laboratory of Plant Nutrition and the Agri-Environment in Northwest China,Ministry of Agriculture and rural areas,Yangling,Shaanxi 712100,China;College Resources&Environmental Engneering,Ludong Univiversity,Yantai,Shandong 264025,China)

机构地区：[1]西北农林科技大学资源环境学院/农业农村部西北植物营养与农业环境重点实验室,陕西杨凌712100 [2]鲁东大学资源与环境工程学院,山东烟台264025

出　　处：《土壤学报》2021年第1期213-224,共12页Acta Pedologica Sinica

基　　金：国家重点研发计划项目(2016YFD0200308);陕西省重点研发计划项目资助(2019ZDLNY01-05-01);“十二五”国家科技支撑计划项目(2012BAD14B11)资助。

摘　　要：为解决麦玉轮作体系小麦秸秆直接粉碎还田存在的弊端,基于多年麦玉秸秆还田定位试验,筛选高产-节本-地力提升为一体的还田模式。选择4种还田模式,即小麦玉米秸秆均不还田(WN-MN,CK1)、小麦玉米秸秆均粉碎还田(WC-MC,CK2)、小麦高留茬还田(WH-MN)和小麦高留茬-玉米粉碎还田(WH-MC)为研究对象,比较其产量表现、土壤有机碳贮量盈亏、碳库管理指数等指标,评价将小麦秸秆粉碎还田改成高留茬还田后形成的还田模式与两季秸秆均粉碎还田的优劣。结果表明,与WN-MN相比,WC-MC和WH-MC的土壤碳储量分别增加24.23%和16.05%;与试验开始前土壤有机碳储量相比,4种还田模式的土壤碳固持为–0.83~6.14 Mg·hm^(–2);维持土壤初始碳储量水平的最小碳投入量为4.06 Mg·hm^(–2)·a^(–1)。各处理不稳定有机碳组分的含量随着土层加深呈下降趋势。与WN-MN相比,WC-MC、WH-MC和WH-MN显著增加了0~20 cm表层不稳定碳组分的含量;WC-MC和WH-MC也显著增加了各土层的碳库管理指数。2015—2016周年产量,WC-MC、WH-MC平均较其他两个处理分别增加了34.5%、20.1%;2016—2017周年产量,以WH-MC最高,较其他处理平均高出11.1%。小麦高留茬-玉米粉碎还田模式下土壤有机碳储量、不稳定有机碳组分、碳库管理指数和作物产量均较高,且节本增效,表明该模式有利于关中平原麦玉轮作体系粮食生产可持续发展。【Objective】Aiming at overcoming the shortcomings of direct application of crushed straw into the soil under the wheat-maize rotation system,a years-long field experiment was carried out in an attempt to screen out an optimal mode for straw returning that could meet the targets of high yield,cost saving and soil fertility improvement.【Method】The nearly 10 years of field experiment on returning of wheat-maize straw was designed to have four treatments or straw returning modes,namely,(i)no return of either wheat or maize straw(WN-MN,CK1);(ii)return of wheat and maize straw,both crushed(WC-MC,CK2);(iii)leaving high wheat stubblein the field(WH-MN);and(ⅳ)leaving high wheat stubble and returning crushed maize straw(WH-MC).By comparing the treatments in the yield,gain and loss of soil organic carbon stock,carbon pool management index and other indices,advantages and disadvantages of the treatments were analyzed.【Result】Results show that Treatment of WC-MC and WH-MC was 81%and 243%,respectively,higher than the other two treatments(WH-MN,WN-MN).and 24.23%and 16.05%,respectively,higher than Treatment WN-MN in SOC stock.Compared with the SOC stock of the soil prior to the experiment,carbon sequestration of the four treatments varied in the range of–0.83-6.14 Mg·hm^(–2).Both sequestered C and non-sequestered C were positively related to cumulative carbon input,indicating that high-amount straw returning is more conducive to carbon sequestration.The minimum carbon input to maintain the basic organic carbon balance was 4.06 Mg·hm^(–2)·a^(–1).The labile fraction of SOC(LFSOC)in each treatment decreased with the increase in soil depth.Compared with Treatment WN-MN,Treatment WC-MC,WH-MC and WH-MN increased LFSOC content in the 0~20 cm layer.Among them,the labile fraction of SOC(active organic carbon,dissolved organic carbon,microbial biomass carbon,hot water soluble carbon and particulate organic carbon)was the highest in Treatment WC-MC,and then in Treatment WH-MC,both of which were significantly higher

关 键 词：有机碳固存 碳库管理指数 秸秆还田模式 不稳定碳组分 

分 类 号：S158.3[农业科学—土壤学]