粪/菌秸秆条带混施对黑土有机无机复合体组成及有机碳分布特征的影响

Effects of manure/biological agent-straw strip mixing on the composition of organo-inorganic complexes and characteristics of organic carbon distribution in black soil

为探究玉米秸秆混施畜禽粪/生物菌剂条带还田条件下黑土有机无机复合体组成及有机碳分布变化特征,本研究于2020年4月在吉林省榆树市黑土区按等碳原则进行1次条带施肥,第2年条带变苗带不施肥,秸秆原位粉碎后,将下茬作物播种行上的秸秆向两侧休闲带堆放形成秸秆覆盖条带,进行连续两年的秸秆原位还田试验。本试验共设4个处理,即条带秸秆覆盖+鸡粪(SO)、条带秸秆覆盖+牛粪(SN)、条带秸秆覆盖+生物菌剂(SJ)和条带秸秆覆盖(SCK)。采用胶散分组法提取有机无机复合体,分为水质分散组(G0)、钠质分散组(G1)和超声分散组(G2)。结果表明:添加畜禽粪及菌剂的处理土壤各组分复合体及其碳含量相比SCK有所增加,SJ处理增加最多,2022年SJ处理G0复合体含量和其碳含量分别增加38 g∙kg^(−1)和1.74 g∙kg^(−1)。各畜禽粪及菌剂处理不同组分复合体含量及其有机碳含量存在一定差异。2021年,SJ和SO处理G1复合体含量相比SN处理显著增加33.46~37.66 g∙kg^(−1),有机碳含量增加0.69~0.78 g∙kg^(−1);SJ、SO处理G2复合体有机碳含量相比SN处理也显著增加。2022年,SJ、SO处理G0复合体有机碳含量与SN处理相比增加显著,其最高增加量为1.02 g∙kg^(−1);SJ处理G1复合体含量相比SO、SN处理分别显著增加41.25 g∙kg^(−1)、49.92 g∙kg^(−1);SJ处理G2复合体有机碳含量最高。两年间,SJ处理G0复合体含量相比SO处理增加23.35~23.74 g∙kg^(−1)。扫描电镜和X射线衍射物相分析结果表明,粪/菌秸秆混施有效保持了复合体表面结构,提高了有机碳转化率。综上,玉米秸秆混施生物菌剂处理更有利于土壤肥力的提升和土壤碳固存的增强,可选为最优还田模式。

Strip fertilization was conducted in the black soil area of Yushu City,Jilin Province,in April 2020 according to the principle of equal carbon to explore the composition and distribution characteristics of organo-inorganic complexes in black soil under the mixed application of corn straw and livestock manure/microbial agent strips returning to the field.In the second year,the strip was changed to a planting strip without fertilization.After the straw was crushed in situ,it on the next crop sowing row was stacked towards the fallow zone on both sides to form a straw-covering strip,and two consecutive years of in situ straw-returning experiments were conducted.This experiment included four treatments:strip straw cover+chicken manure(SO),strip straw cover+cow manure(SN),strip straw cover+biological agent(SJ),and strip straw cover(SCK).Organo-inorganic complexes were extracted using the geldispersion grouping method and divided into aqueous(G0),sodium(G1),and ultrasonic(G2)dispersion groups.The results showed that adding animal manure and biological agents increased the soil component complexes and their carbon content compared to SCK,with the highest increases of G0 observed under the SJ treatment in 2022 at 38 g∙kg^(−1) and 1.74 g∙kg^(−1),respectively.In 2021,among the treatments of animal manure and biological agents,the G1 complex content under the SJ and SO treatments significantly increased by 33.46–37.66 g∙kg^(−1) compared to that under the SN treatment,and the organic carbon content increased by 0.69–0.78 g∙kg^(−1).The organic carbon content of the G2 complex under SJ and SO treatments showed significant differences compared to that under SN treatment.In 2022,among the animal manure and bacterial agent treatments,the carbon content of the G0 complex under SJ and SO treatments increased significantly compared to that under SN treatments,with the highest increase being 1.02 g∙kg^(−1).The content of the G1 complex under SJ treatment significantly increased by 41.25 g∙kg^(−1) and 49.92 g∙kg^(−1) compared to that under SO and SN treatments,respectively.The SJ treatment showed the highest organic carbon content in the G2 complex.Between two years,the content of the G0 complex under SJ treatment increased by 23.35–23.74 g∙kg^(−1) compared to that under SO treatment.Scanning electron microscope and X-ray diffraction phase analysis showed that the mixed application of manure/biological agent straw effectively maintained the surface structure of the complexes and improved the organic carbon conversion rate.In summary,applying corn straw mixed with biological agents is more conducive to improving soil fertility and enhancing soil carbon sequestration and can be selected as the optimal returning mode.