氮肥配施秸秆对水稻土氨基糖的影响

发布时间：2018-04-25 16:56

  本文选题：肥料氮素 + 秸秆　； 参考：《沈阳农业大学》2017年硕士论文

【摘要】：秸秆还田作为一种改善土壤理化性质,提高土壤肥力的有效措施受到了极大的关注和广泛的应用。一方面高碳氮比的作物秸秆还田能够刺激土壤微生物的氮需求,增强土壤微生物对无机氮素的固持,使更多的肥料氮以易分解的有机过渡态在土壤中保存,有利于提高肥料氮的利用率。另一方面秸秆配施化肥为土壤微生物提供了大量能源和营养,必然会对土壤微生物产生剧烈的影响,并进一步影响土壤微生物相关的土壤碳氮循环过程。本研究拟通过盆栽水稻试验,利用~(15)N标记技术,研究秸秆还田条件下无机肥料氮在土壤及其团聚体中的截留和在土壤氨基糖中'氨基位"中富集情况,以期进一步了解土壤及其团聚体中氮素更新和微生物转化情况,揭示秸秆还田对水稻土无机肥料氮的微生物转化过程的影响机制,为农田肥料氮素的高效管理提供理论依据。主要结论如下:(1)相对于不施肥的情况,氮肥配施秸秆增加了土壤和各粒级团聚体中TN含量;与单施氮肥相比,增施高量秸秆增加了 ~(15)N 土壤中的固持,且促使更多的肥料来源~(15)N在粒径2000μm团聚体中积累下来。(2)无论是单施氮肥或是氮肥配施秸秆,对土壤氨基糖积累都有促进作用,尤其是在高量秸秆施入时,促进作用更加明显。相对于单施氮肥,增施秸秆处理显著增加了土壤中新合成氨基糖含量,有利于肥料~(15)N在土壤中的微生物固定。(3)土壤团聚体,尤其是250μm团聚体是水稻土壤氨基糖重要的储存库。秸秆配施氮肥使氨基糖的富集由微团聚体向小团聚体中转移;氮肥配施低量秸秆增加了粉粒+黏粒对氨基糖积累的相对贡献,而配施中高量秸秆处理,则促使大团聚体对土壤氨基糖的贡献加强。(4)同位素分析表明,与单施氮肥相比,施加中高量秸秆促进了各粒级团聚体中~(15)N-氨基糖的微生物合成,但土壤和团聚体中新增加氨基糖的主要来自与土壤或秸秆引入的氮。(5)在不同粒级团聚体中,微生物对施肥的响应不同,氮肥配施高量秸秆有利于大团聚体中真菌来源氨基糖的积累,而在250μm的团聚体中,细菌对氨基糖积累的贡献增强。(6)在水稻不同生长期分别施入等量~(15)N肥料,~(15)N在土壤及各粒级团聚体中积累量顺序为:基肥分蘖肥拔节孕穗肥,而且基肥施入土壤的~(15)N更易于被微生物固定在土壤中。随着水稻的生长发育,较晚施入的~(15)N易于向大团聚体富集的而减少向53～2000μm团聚体中的富集。综述所诉,土壤250μm粒径团聚体是土壤肥料氮和氨基糖主要储存库,这表明较大粒级土壤团聚体是土壤碳氮微生物转化的重要场所,对维持土壤肥力具有重要作用。增施秸秆虽然没有增加肥料~(15)N在土壤中的截留,但氮肥配施秸秆使更多的肥料氮进入53μm的团聚体中,促进了土壤和团聚体微生物对无机肥料氮的固持,长期来看,这有利于肥料氮的固持和逐渐矿化被农作物利用。
[Abstract]:As an effective measure to improve soil physical and chemical properties and improve soil fertility, straw returning to the field has been paid great attention to and widely used. On the one hand, returning crop straw with high C / N ratio can stimulate the nitrogen demand of soil microbes, enhance the retention of inorganic nitrogen by soil microbes, and make more fertilizer nitrogen be preserved in soil in the organic transition state that is easy to decompose. It is beneficial to increase the utilization rate of fertilizer nitrogen. On the other hand, straw combined with chemical fertilizer provides a large amount of energy and nutrition for soil microorganisms, which will inevitably have a severe impact on soil microorganisms, and further affect the soil microbial related carbon and nitrogen cycling process. In this study, pot rice experiment was conducted to study the retention of inorganic fertilizer nitrogen in soil and its aggregates and the accumulation of 'amino position' in soil amino sugar under the condition of straw returning to the field. In order to further understand the status of nitrogen regeneration and microbial transformation in soil and its aggregates, to reveal the mechanism of straw returning to soil on the microbial transformation process of inorganic fertilizer nitrogen in paddy soil, and to provide theoretical basis for the efficient management of nitrogen in farmland fertilizer. The main conclusions are as follows: compared with no fertilizer application, nitrogen fertilizer combined with straw increased TN content in soil and aggregates, compared with nitrogen fertilizer alone, high straw application increased soil fixation and retention. In addition, more fertilizer sources, I. e. 15N, accumulated in 2000 渭 m aggregates.) both nitrogen fertilizer and straw application promoted the accumulation of amino sugar in soil, especially when straw was applied in high amount. Compared with nitrogen fertilizer alone, the application of straw significantly increased the content of newly synthesized amino sugar in soil, which was beneficial to the microbial fixation of N in soil, especially 250 渭 m aggregate, which was an important storage of amino sugar in rice soil. The accumulation of amino sugar was transferred from microaggregates to small aggregates by applying nitrogen fertilizer in combination with straw, and the relative contribution of silt clay to aminosaccharide accumulation was increased by applying low amount of straw with nitrogen fertilizer, while the medium and high amount of straw was applied with medium and high amount of straw. The results of isotopic analysis showed that the addition of medium and high amount of straw promoted the microbial synthesis of 15N- amino sugar in the aggregates of different grain levels, compared with that of nitrogen fertilizer alone, which promoted the contribution of macroaggregates to soil aminosaccharides. However, the new amino sugar in soil and aggregates mainly came from the nitrogen introduced by soil or straw. In different grain-level aggregates, the response of microbes to fertilization was different. Nitrogen fertilizer combined with high amount of straw was beneficial to the accumulation of fungal amino sugar in large aggregates, but in 250 渭 m agglomerates. The contribution of bacteria to the accumulation of amino sugar was enhanced. 6) in different growth stages of rice, the same amount of N was applied to the soil and the aggregates. The order of accumulation was as follows: basal fertilizer, tiller fertilizer, jointing and booting fertilizer. And the base fertilizer applied to the soil was more easily immobilized by microbes. Along with the growth and development of rice, the late application of Yumi15N was easy to enrich to the large aggregates, but decreased to the 53 ~ 2 000 渭 m agglomerates. In this review, the soil 250 渭 m particle size aggregate is the main storage bank of soil fertilizer nitrogen and amino sugar, which indicates that the larger grain size soil aggregate is an important place for soil carbon-nitrogen microbial transformation and plays an important role in maintaining soil fertility. Although the application of straw did not increase the retention of N in the soil, nitrogen fertilizer combined with straw could make more fertilizer nitrogen into 53 渭 m aggregate, which promoted the fixation of inorganic fertilizer nitrogen by soil and aggregates microbes, and in the long run, This is beneficial to the sequestration and gradual mineralization of fertilizer nitrogen by crops.
【学位授予单位】：沈阳农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S158
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本文编号：1802178