【作者】 刘立志；

【导师】 戴建军；

【作者基本信息】 东北农业大学 ， 植物营养学， 2020， 硕士

【摘要】 东北地区是我国水稻的重要生产基地,每年会产生大量的水稻秸秆,但由于秋季水稻收获后气温逐渐降低,水稻秸秆C/N比高,微生物活动减弱,秸秆腐解缓慢。本文通过不同耕作方式对稻草还田土壤有机碳组分、水稻产量,以及外源碳、氮对土壤微生物量碳和土壤酶活性影响的研究,探讨微生物量碳和土壤酶活性与土壤有机碳组分和土壤速效养分之间的关系,以期促进东北地区稻草还田腐解转化,提高水稻产量提供参考依据。本试验包括两部分:第一部分为田间小区试验,探究不同耕作方式对稻草还田土壤碳组分和水稻产量的影响。试验设四个处理,分别为:秸秆不还田+秋翻后旋耕+水搅浆+捞平(J),秸秆还田+秋翻后旋耕+水搅浆+捞平(SJ),秸秆还田+秋翻后旋耕+不搅浆+捞平(SP),秸秆还田+逆旋耕深埋处理+不搅浆+捞平(SDP)。第二部分为土壤培养试验,探究外源碳、氮对稻草还田土壤微生物量碳、土壤酶活性、碳组分与土壤速效养分含量的影响。试验为完全随机试验设计,2因素3水平,其中碳三个水平(T0:0 mg·kg-1,T1:13.34 mg·kg-1,T2:26.68 mg·kg-1),氮三个水平(N0:0 mg·kg-1,N1:26.8 mg·kg-1,N2:53.6 mg·kg-1),试验共九个处理。试验结果如下:1.水稻秸秆还田下,不同耕作方式可以显著增加土壤总有机碳、水溶性有机碳、总腐殖酸态碳、游离腐殖酸态碳含量和水稻产量。水稻秸秆还田后,SDP耕作处理土壤总有机碳、水溶性有机碳含量与水稻产量均显著高于其他处理;而水稻秸秆还田的处理除SP耕作处理外水稻产量均高于不还田处理J。水稻产量与土壤水溶性有机碳、游离腐殖酸态碳呈极显著或显著正相关,与总有机碳和总腐殖酸态碳相关性未达显著水平。2.土壤添加水稻秸秆配合外源碳、氮可以显著增加土壤微生物量碳、酶活性、碳组分与土壤速效养分含量。土壤培养至第10天时各处理土壤蔗糖酶和纤维素酶活性达到最高,其中同时添加碳、氮处理可显著增加土壤蔗糖酶活性,添加低氮处理可显著提高土壤纤维素酶活性;各处理土壤微生物量碳含量、脲酶活性在培养第30天时达最高,其中添加高氮处理可显著提高土壤脲酶活性,同时添加高水平碳、氮处理可显著增加土壤微生物量碳含量。土壤总有机碳、水溶性有机碳与总腐殖酸态碳含量均比培养第0天时略有下降,其中同时添加碳、氮处理可显著增加土壤水溶性有机碳含量,添加外源碳、氮的处理土壤总有机碳与总腐殖酸态碳含量差异不显著。土壤碱解氮、速效磷与速效钾含量均比培养第0天时有所升高,其中添加高氮处理可显著提高土壤碱解氮含量,同时添加碳、氮处理可显著提高土壤速效钾含量,添加外源碳、氮的处理土壤速效磷含量差异不显著。综合田间小区试验与土壤培养试验得出,不同耕作方式可以提高稻草还田下土壤碳组分含量和水稻产量;外源碳、氮可以增加稻草还田下土壤微生物碳的含量,加强相关土壤酶的活性,促进水稻秸秆腐解中间产物的形成,增加土壤有机碳组分与土壤速效养分含量。更多还原

【Abstract】 Northeast China is the main grain production area in China,and a lot of crop straws are produced every year.However,after the rice harvest in autumn,the temperature gradually decreases,the straw C/N ratio is high,the decomposition is slow.In this paper,the effects of returning straw to the field on soil organic carbon components,rice yield,and the effects of exogenous carbon and nitrogen on soil microbial biomass carbon and soil enzyme activity were studied,to explore the relationship between microbial biomass carbon and soil enzyme activity and soil organic carbon components and soil available nutrients,with a view to promoting the decomposition and conversion of rice straw in the Northeast,and providing a reference basis for increasing rice yield.The experiment consisted of two parts:The first part was a field plot experiment to explore the effects of different tillage methods on the soil carbon composition and rice yield.The experiment had four treatments,which were:straw not returned to field+autumn tillage and rotation tillage+water stirring pulp+fishing level(J),straw return to field+autumn tillage and rotation tillage+water stirring pulp+fishing level(SJ),straw return to field+autumn turning and post-rotation tillage+no pulping+fishing level(SP),straw return to field+reverse rotation tillage treatment+no stirring pulp+fishing level(SDP);The second part was the soil incubation experiment,to explore the effects of exogenous carbon and nitrogen on the soil carbon component,soil enzyme activity,and soil available nutrient content of rice straw returned to the field.The test was a completely randomized trial design,2 factors and3 levels,three levels of carbon(T0:0 mg·kg-1,T1:13.34 mg·kg-1,T2:26.68 mg·kg-1),three levels of nitrogen(N0:0 mg·kg-1,N1:26.8 mg·kg-1,N2:53.6 mg·kg-1),a total of nine treatments.The test results were as follows:1.Rice straw was returned to the fields,different village methods could increase the content of soil total organic carbon,water-soluble organic carbon,total humic acid carbon and corbon form free humic acid.After the rice straw was returned to the field,SDP tillage treatment soil total organic carbon,water-soluble organic carbon and rice yield were significantly higher than other treatments;Except SP,the treatment of returning rice straw to the field is higher than that of the treatment without returning J.Rice yield was extremely significant or significantly positively correlated with soil water-soluble organic matter and carbon form free humic acid,and the correlation with total organic matter and total humic acid carbon did not reach a significant level.2.Adding rice straw to the soil combined with exogenous carbon and nitrogen could significantly increase soil microbial biomass carbon,enzyme activity,carbon components and soil available nutrient content.The soil sucrase and cellulase activities reached the highest level after the soil was incubated to the 10th day.The simultaneous addition of carbon and nitrogen treatments could significantly increase soil sucrase activity,and the addition of low nitrogen treatment could significantly increase soil cellulase activity;The soil microbial biomass carbon content and urease activity of each treatment reached the highest on the 30th day of incubation.The addition of high nitrogen treatment could significantly increase soil urease activity,while the addition of high levels of carbon and nitrogen treatment could significantly increase soil microbial biomass carbon content.The contents of total organic carbon,water-soluble organic carbon and total humic acid carbon in the soil were slightly lower than that on the 0th day of incubation.The simultaneous addition of carbon and nitrogen treatment could significantly increase the content of soil water-soluble organic carbon.the content of total organic carbon and total humic acid carbon in the soil treated with exogenous carbon and nitrogen was not significantly different.The contents of soil alkaline nitrogen,available phosphorus and available potassium were all higher than that on the 0th day of incubation.the addition of high nitrogen treatment could significantly increase the soil alkaline nitrogen content,while the addition of carbon and nitrogen treatment could significantly increase the soil available potassium content.The treatment of source carbon and nitrogen showed no significant difference in soil available phosphorus content.Comprehensive field plot experiments and soil cultivation experiments had shown that different tillage methods could increase soil carbon content and rice yield after straw returning to the field;Exogenous carbon and nitrogen could increase the content of soil microbial carbon,enhance the activity of related soil enzymes,accelerate the decomposition of returned rice straw,increase soil organic carbon components and soil nutrient content after returning rice straw to the field.更多还原