膨润土与秸秆配施对燕麦根区土壤有机碳组分和丛植菌根真菌多样性的影响

Effect of Combined Application of Bentonite and Straw on Soil Organic Carbon Components and the Diversity of Arbuscular Mycorrizal Fungi in Root Zone

为探究膨润土与秸秆配施后燕麦根区不同土层土壤有机碳及其组分含量和丛植菌根真菌(arbuscular mycorrizal fungi, AMF)多样性变化,在黄土高原旱作区燕麦单作田间定位试验中,连续3年进行秸秆还田(S)、单施膨润土(B)、膨润土配施秸秆(H)、不施膨润土和秸秆不还田(CK)4个处理,研究不同处理下不同土层土壤有机碳及其组分含量和AMF多样性的差异及其相关性。结果表明,与CK相比,B、S和H处理能不同程度提高土壤总有机碳(TOC)和不同组分有机碳[可溶性有机碳(DOC)、轻组有机碳(LFOC)、颗粒有机碳(POC)、粗颗粒有机碳(CPOC)和细颗粒有机碳(FPOC)]含量及其分配比例,0~20 cm土层增幅大于20~40 cm土层。与CK相比,其他处理提高了0~20 cm土层土壤TOC、DOC、LFOC、POC、CPOC和FPOC含量,其中H处理提高显著(P<0.05),依次提高了19.55%、27.21%、54.69%、56.35%、54.72%和31.11%;各处理增加了矿物结合态有机碳(MOC)含量,增幅为2.59%~6.03%,但差异不显著。与CK相比,H处理显著提高土壤LFOC/TOC、POC/TOC、CPOC/TOC和POC/MOC,增幅分别为29.71%、30.45%、30.49%和50.91%;显著提高了0~20 cm土层土壤AMF香农指数和辛普森指数,增幅分别为60.87%和16.05%。相关性分析表明,香农指数与土壤CPOC含量呈极显著正相关(P<0.01),与DOC含量呈显著正相关(P<0.05);辛普森指数与LFOC含量呈显著正相关。综上,膨润土与秸秆配施可不同程度提高燕麦耕层土壤有机碳及其组分含量、AMF多样性,可用于改善黄土高原旱作区土壤质量。

In order to explore the changes of soil organic carbon and its components and the diversity of arbuscular mycorrhizal fungi(AMF)in different soil layers of oat root zone after combined application of bentonite and straw,four treatments of straw returning(S),single application of bentonite(B),combined application of bentonite and straw(H),no application of bentonite and no straw returning(CK)were carried out in the oat monoculture field experiment in arid area of the Loess Plateau for three consecutive years.The effects of combined application of bentonite and straw on soil organic carbon and its components and AMF diversity in different soil layers were studied and the correlation between them were analyzed.The results showed that,compared with the control,bentonite,straw returning to field and combined application of bentonite and straw can increase the content and distribution ratio of total organic carbon(TOC),organic carbon of different components[dissolved organic carbon(DOC),light fraction organic carbon(LFOC),particulate organic carbon(POC),coarse particulate organic carbon(CPOC)and fine particulate organic carbon(FPOC)]in soil to different degrees.The increasing effect of 0~20 cm soil layer is better than that of 20~40 cm soil layer.Compared with CK,the contents of TOC,DOC,LFOC,POC,CPOC,and FPOC in 0~20 cm soil layer were increased by each treatment,and those under H treatment were significantly increased by 19.55%,27.21%,54.69%,56.35%,54.72%,and 31.11%,respectively.The content of mineral bound organic carbon(MOC)was increased by 2.59%-6.03%,and the difference was not significant.Compared with CK,H treatment significantly increased LFOC/TOC,POC/TOC,CPOC/TOC,and POC/MOC by 29.71%,30.45%,30.49%,and 50.91%,respectively.H treatment significantly increased the AMF Shannon index and Simpson index of 0-20 cm soil layer by 60.87%and 16.05%,respectively.Correlation analysis showed that Shannon index was positively correlated with soil coarse organic carbon and soluble organic carbon.Simpson index was positively correlated with light organic carbon.In conclusion,the combined application of bentonite and straw has great significance for improving soil quality in arid areas of the Loess Plateau by increasing soil organic carbon and its component contents in different soil layers,increasing AMF diversity,and increasing soil organic carbon pool in farmland.