连续水稻秸秆还田年限对麦季土壤养分含量及温室气体排放的影响

发布时间：2018-09-18 10:13

【摘要】：当今世界上普遍重视秸秆还田作为一项重要的农艺措施的应用,前人研究明确秸秆还田具有培肥地力、提升土壤质量、降低化学肥料施用水平的增产效应,但秸秆还田对当季作物生产存在一定的负效应,影响秸秆还田技术的推广应用。本试验于2014-2016年在扬州大学江苏省作物遗传生理重点试验室试验场进行。以扬辐麦4号为试验材料,通过长期水稻秸秆全量还田定位试验,研究水稻秸秆全量还田年限对土壤养分状况、温室气体排放和小麦籽粒产量及品质的影响,探索不同水稻秸秆全量还田年限下扬辐麦4号高产优质栽培技术途径,以期为水稻秸秆全量还田下小麦高产、优质、高效、低碳的栽培提供理论依据和技术支撑。主要结果如下:1、水稻秸秆全量还田1～3年的产量低于不还田处理,减产的主要原因是降低了穗数。水稻秸秆全量还田4-7年处理的籽粒产量高于不还田处理,主要是由于水稻秸秆全量还田增加了千粒重和穗粒数,弥补了穗数的降低。相同施氮量不同氮肥运筹以5:1:2:2氮肥运筹的籽粒产量高于3:1:3:3氮肥运筹和7:1:2:0氮肥运筹。秸秆全量还田对小麦籽粒品质有一定的调节效应,水稻秸秆全量还田增加了小麦籽粒蛋白质含量、籽粒硬度。秸秆还田后,小麦籽粒湿面筋含量、沉降值、出粉率均有所下降,随着还田年限的增加,小麦籽粒湿面筋含量、沉降值、出粉率逐渐增加。2、水稻秸秆全量还田小麦整个生育期内土壤硝态氮(N03--N)、铵态氮(NH4+—N)、速效磷、速效钾含量呈动态变化,在追肥不同时期变幅较大。小麦播种后由于秸秆降解过程中微生物固定土壤中的氮素,导致各层次土壤硝态氮和铵态氮含量降低,影响小麦苗期生长发育。随着小麦生育进程的推移,秸秆由降解期逐渐进入释氮期,生育中后期特别是抽穗开花期之后水稻秸秆全量还田处理的各层次土壤硝态氮和铵态氮含量升高,为小麦植株生育中后期氮素的吸收积累提供了良好的养分供应。水稻秸秆全量还田提高了土壤耕层硝态氮、铵态氮、速效磷、速效钾、有机质含量,且随着还田年限的增加,各层次土壤铵态氮、速效磷、速效钾、有机质含量逐渐增加,说明持续水稻秸秆全量还田有利于提高土壤肥力水平。3、水稻秸秆全量还田提高了土壤当季麦田CH4和CO2的累积排放量,多年水稻秸秆全量还田麦田CO2排放虽有增加趋势,但同时降低了 N2O的累积排放量。水稻秸秆全量还田提高了麦季净GWP,且随着还田年限的增加而升高。虽然水稻秸秆全量还田较未还田处理增加了温室气体的净排放量,由于还田秸秆中的部分碳(C)源和N源在土壤中转化为有机质和硝铵态N,因而水稻秸秆全量还田对当季麦田具有一定的综合减排效果,且秸秆还田年限越长,减排效果越好。4、水稻秸秆全量还田会影响小麦幼苗的生长,造成麦苗弱小生长缓慢,茎蘖数降低,随着还田年限的增加,土壤养分供应能力逐渐上升,秸秆还田的不利影响也逐渐减小。随着还田年限的增加,小麦群体茎蘖数、LAI、干物质积累量均逐渐增加。花后干物质的积累量占籽粒干重的比例在74.34%-83.77%左右,花后干物质积累量与小麦籽粒产量间呈显著的线性关系。5、水稻秸秆全量还田有利于提高剑叶SPAD和净光合速率,且随还田年限的增加,效应升高。这可能是由于随着还田年限的增加,秸秆腐解后释放的氮素为小麦中后期生长提供了比较充足的氮素,延缓了植株的衰老。氮肥运筹5:1:2:2和3:1:3:3处理的剑叶SPAD值和净光合速率高于7:1:2:0处理。水稻秸秆全量还田条件下,在小麦生育期间氮肥运筹既要适当增加基苗肥用量以利壮苗早发,又要合理使用拔节孕穗肥有利于延缓植株的衰老,提高小麦花后剑叶光合生产能力和籽粒灌浆能力。6、水稻秸秆全量还田提高了小麦植株氮素、磷素积累量,提高了小麦营养器官氮素、磷素转移量、转移效率和对籽粒贡献率。水稻秸秆全量还田条件下采用5:1:2:2和3:1:3:3氮肥运筹施肥方式更有利于小麦生育期内氮素、磷素的吸收积累。水稻秸秆全量还田年限的增加,有利于提高小麦营养器官氮素、磷素转移量、转移效率和对籽粒贡献率。说明连续水稻秸秆全量还田有利于提高小麦花后氮素、磷素的吸收、积累和转运,有利于提高小麦产量水平。
[Abstract]:Nowadays, the application of straw returning as an important agronomic measure is generally emphasized in the world. Previous studies have made it clear that straw returning has the effect of increasing fertility, improving soil quality and reducing the level of chemical fertilizer application. However, straw returning has a certain negative effect on crop production in the current season and affects the popularization and Application of straw returning technology. The experiment was conducted in the Key Laboratory of Crop Genetic Physiology, Jiangsu Province, Yangzhou University from 2014 to 2016. Yangfumai 4 was used as the experimental material to study the effects of years of rice straw returning to the field on soil nutrient status, greenhouse gas emissions and wheat grain yield and quality. In order to provide theoretical basis and technical support for wheat cultivation with high yield, high quality, high efficiency and low carbon, Yangfumai 4 was planted under different years of returning rice straw to field. The main results are as follows: 1. The yield of rice straw returned to field for 1-3 years was lower than that of non-returning treatment, and the yield of wheat was reduced. The grain yield of rice straw returned to the field for 4-7 years was higher than that of the non-returned field, mainly because the total amount of rice straw returned to the field increased 1000-grain weight and the number of grains per panicle, which made up for the decrease of panicle number. The total amount of rice straw returned to the field increased the protein content and hardness of wheat grain. After the straw returned to the field, the wet gluten content, sedimentation value and flour yield of wheat grain decreased. With the increase of returning years, the wet gluten content, sedimentation value and flour yield of wheat grain decreased. The content of soil nitrate nitrogen (N03 - N), ammonium nitrogen (NH4 + - N), available phosphorus and potassium in the whole growth period of wheat returned to field with rice straw increased gradually. The content of ammonium nitrogen decreased and affected the growth and development of wheat seedlings. With the development of wheat, straw gradually entered the stage of nitrogen release from degradation, and the content of nitrate nitrogen and ammonium nitrogen increased in all layers of soil returned to the field at the middle and late growth stages, especially after heading and flowering stages. The total amount of rice straw returned to the field increased the contents of nitrate nitrogen, ammonium nitrogen, available phosphorus, available potassium and organic matter in the plough layer, and with the increase of returning years, the contents of ammonium nitrogen, available phosphorus, available potassium and organic matter in all layers of soil increased gradually, indicating that the continuous total amount of rice straw returned to the field was beneficial to improving the soil quality. Fertility level. The total amount of straw returned to the field increased the net greenhouse gas emissions compared with the untreated straw. As part of the carbon (C) and nitrogen sources in the straw returned to the field were converted into organic matter and ammonium nitrate N in the soil, the total amount of rice straw returned to the field had a certain comprehensive emission reduction effect on the wheat field in the current season, and the longer the straw returned to the field, the better the emission reduction effect. 4 The total amount of straw returned to the field will affect the growth of wheat seedlings, resulting in the weak growth of wheat seedlings slowly, the number of tillers decreased, with the increase of years of returning to the field, the soil nutrient supply capacity gradually increased, the adverse effects of straw returned to the field gradually decreased. The ratio of dry matter accumulation to grain dry weight was 74.34%-83.77%. There was a significant linear relationship between dry matter accumulation after anthesis and grain yield of wheat. The SPAD value and net photosynthetic rate of flag leaves treated with 5:1:2:2 and 3:1:3:3 nitrogen fertilizer application were higher than those treated with 7:1:2:0. Under the condition of returning rice straw to field, the amount of nitrogen fertilizer application during wheat growth period should be increased appropriately. In order to make the seedlings grow early and use booting fertilizer rationally, it is helpful to delay the senescence of the plant, improve the photosynthetic capacity of flag leaf and grain filling capacity after anthesis. 6. The total amount of rice straw returned to the field increased the nitrogen and phosphorus accumulation of wheat plants, and increased the nitrogen and phosphorus transfer capacity of wheat vegetative organs, transfer efficiency and contribution to grain. The application of 5:1:2:2 and 3:1:3:3 nitrogen fertilizer was more beneficial to the uptake and accumulation of nitrogen and phosphorus during wheat growth period. The increase of the years of rice straw returning to the field was beneficial to the increase of nitrogen, phosphorus transfer, transfer efficiency and contribution rate of Wheat Nutrient organs. Total returning to field was beneficial to increase the absorption, accumulation and transportation of nitrogen and phosphorus after anthesis, and to increase the yield level of wheat.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S512.1;S141.4

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