秸秆还田量对陇中旱作麦田土壤团聚体稳定性和有机碳含量的影响  

Effects of straw returning amount on stability of soil aggregates and organic carbon content in dryland wheat field of the Loess Plateau

作　　者：王永栋 武均[1,2] 蔡立群[1,2,3] 张仁陟 WANG Yongdong;WU Jun;CAI Liqun;Zhang Renzhi(College of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou, Gansu 730070, China;Gansu Provincial Key Laboratory of Arid Land Crop Science, Gansu Agricultural University, Lanzhou, Gansu 730070, China;Gansu Engineering Research Center for Agricultural Water-saving, Lanzhou, Gansu 730070, China)

机构地区：[1]甘肃农业大学资源与环境学院,甘肃兰州730070 [2]甘肃农业大学甘肃省干旱生境作物学重点实验室,甘肃兰州730070 [3]甘肃省节水农业工程技术研究中心,甘肃兰州730070

出　　处：《干旱地区农业研究》2022年第2期232-239,249,共9页Agricultural Research in the Arid Areas

基　　金：甘肃省自然科学基金(20JR10RA543);国家自然科学基金(41661049;31571594)。

摘　　要：为探明秸秆还田后土壤团聚体与有机碳的变化特征和作用机制,依托2019年布设于甘肃省定西市李家堡镇的不同秸秆还田试验,设置两种秸秆类型:小麦秸秆和玉米秸秆,秸秆还田量分别为:0(CK)、3500(低量)、7000(中量)、14000 kg·hm^(-2)(高量),研究了秸秆还田对陇中黄土高原旱作农田土壤团聚体稳定性和有机碳的影响。结果表明:土壤机械稳定性团聚体以>0.25 mm团聚体为主,且随土层加深粒径逐渐增大,水稳性团聚体均与之相反;秸秆还田较不还田处理的机械稳定性和水稳性<0.25 mm粒级团聚体含量分别降低了3.53%~21.74%和2.73%~8.95%,土壤机械稳定性和水稳性团聚体平均重量直径MWD、几何平均直径GMD的提升幅度最大分别达到16.29%、30.12%和20.93%、12.12%,团聚体破碎率PAD降低了2.53%~13.23%,在中量秸秆还田时效果最好,且玉米秸秆比小麦秸秆效果更明显。秸秆还田提升了土壤有机碳含量,且在表层土壤秸秆还田量越高,对土壤有机碳的提升效果越显著,其中玉米秸秆高量还田处理的土壤有机碳含量较CK显著提高了31.37%;下层土壤小麦和玉米秸秆分别在中量和高量还田下对土壤有机碳含量提升幅度最大,较CK分别显著提高了29.85%和36.31%。相关性和多元回归分析结果显示,土壤有机碳与机械稳定性和水稳性团聚体的稳定指数分别呈显著和极显著正相关关系,而PAD与土壤有机碳呈极显著负相关关系;土壤有机碳与GMD的拟合方程更适合描述土壤有机碳与团聚体稳定性间的关系。综上,本研究认为在玉米秸秆还田量为7000 kg·hm^(-2)时最适宜改良土壤团聚体结构和提升土壤固碳潜力,有效改善土壤质量。This study aimed to investigate the effects of straw returning on stability of soil aggregates and organic carbon in the dry farmland of the Loess Plateau in central Gansu.Different straw returning experiments were conducted in Lijiapu Town,Dingxi City,Gansu Province in 2019.The two straw types were wheat and corn,and the straw returning amount included 0(CK),3500 kg·hm^(-2)(low amount),7000 kg·hm^(-2)(medium amount)and 14000 kg·hm^(-2)(high amount).The results showed that soil mechanically stable aggregates were>0.25 mm aggregates as the main aggregates,and the particle size gradually increased with the deepening of soil layer,while that of water-stable aggregates were the opposite.When compared the treatment of straw returning to the field with no returning to the field,the contents of<0.25 mm mechanical stability and water stability aggregates decreased by 3.53%~21.74%and 2.73%~8.95%,respectively.The average weight diameter MWD and geometric average diameter GMD of soil mechanical stability aggregates increased by 16.29%and 30.12%,respectively,while that of water stability aggregates increased by 20.93%and 12.12%,respectively.The aggregate fragmentation rate PAD decreased by 2.53%~13.23%.The effect of medium straw was the best,and the effect of corn straw was more significant than that of wheat straw.Straw returning increased soil organic carbon content,and the higher the amount of straw returning on the soil surface,the more significant the improvement effect on soil organic carbon became.Compared with CK,the soil organic carbon content in high amount of corn straw returning to the field was significantly increased by 31.37%.In the subsoil,the medium wheat straw returning and high corn straw returning significantly increased soil organic carbon content by 29.85%and 36.31%,respectively,when compared with CK.The results of correlation and multiple regression analysis showed that soil organic carbon had a significant positive correlation with the stability index of mechanically stable aggregates,and extremely

关 键 词：秸秆还田量 土壤团聚体 土壤有机碳 旱作麦田 

分 类 号：S152[农业科学—土壤学] S19[农业科学—农业基础科学]