發(fā)布時間：2018-04-25 16:56

  本文選題：肥料氮素 + 秸稈　； 參考：《沈陽農(nóng)業(yè)大學(xué)》2017年碩士論文

【摘要】：秸稈還田作為一種改善土壤理化性質(zhì),提高土壤肥力的有效措施受到了極大的關(guān)注和廣泛的應(yīng)用。一方面高碳氮比的作物秸稈還田能夠刺激土壤微生物的氮需求,增強(qiáng)土壤微生物對無機(jī)氮素的固持,使更多的肥料氮以易分解的有機(jī)過渡態(tài)在土壤中保存,有利于提高肥料氮的利用率。另一方面秸稈配施化肥為土壤微生物提供了大量能源和營養(yǎng),必然會對土壤微生物產(chǎn)生劇烈的影響,并進(jìn)一步影響土壤微生物相關(guān)的土壤碳氮循環(huán)過程。本研究擬通過盆栽水稻試驗(yàn),利用~(15)N標(biāo)記技術(shù),研究秸稈還田條件下無機(jī)肥料氮在土壤及其團(tuán)聚體中的截留和在土壤氨基糖中'氨基位"中富集情況,以期進(jìn)一步了解土壤及其團(tuán)聚體中氮素更新和微生物轉(zhuǎn)化情況,揭示秸稈還田對水稻土無機(jī)肥料氮的微生物轉(zhuǎn)化過程的影響機(jī)制,為農(nóng)田肥料氮素的高效管理提供理論依據(jù)。主要結(jié)論如下:(1)相對于不施肥的情況,氮肥配施秸稈增加了土壤和各粒級團(tuán)聚體中TN含量;與單施氮肥相比,增施高量秸稈增加了 ~(15)N 土壤中的固持,且促使更多的肥料來源~(15)N在粒徑2000μm團(tuán)聚體中積累下來。(2)無論是單施氮肥或是氮肥配施秸稈,對土壤氨基糖積累都有促進(jìn)作用,尤其是在高量秸稈施入時,促進(jìn)作用更加明顯。相對于單施氮肥,增施秸稈處理顯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)土壤團(tuán)聚體,尤其是250μm團(tuán)聚體是水稻土壤氨基糖重要的儲存庫。秸稈配施氮肥使氨基糖的富集由微團(tuán)聚體向小團(tuán)聚體中轉(zhuǎn)移;氮肥配施低量秸稈增加了粉粒+黏粒對氨基糖積累的相對貢獻(xiàn),而配施中高量秸稈處理,則促使大團(tuán)聚體對土壤氨基糖的貢獻(xiàn)加強(qiáng)。(4)同位素分析表明,與單施氮肥相比,施加中高量秸稈促進(jìn)了各粒級團(tuán)聚體中~(15)N-氨基糖的微生物合成,但土壤和團(tuán)聚體中新增加氨基糖的主要來自與土壤或秸稈引入的氮。(5)在不同粒級團(tuán)聚體中,微生物對施肥的響應(yīng)不同,氮肥配施高量秸稈有利于大團(tuán)聚體中真菌來源氨基糖的積累,而在250μm的團(tuán)聚體中,細(xì)菌對氨基糖積累的貢獻(xiàn)增強(qiáng)。(6)在水稻不同生長期分別施入等量~(15)N肥料,~(15)N在土壤及各粒級團(tuán)聚體中積累量順序?yàn)?基肥分蘗肥拔節(jié)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。隨著水稻的生長發(fā)育,較晚施入的~(15)N易于向大團(tuán)聚體富集的而減少向53～2000μm團(tuán)聚體中的富集。綜述所訴,土壤250μm粒徑團(tuán)聚體是土壤肥料氮和氨基糖主要儲存庫,這表明較大粒級土壤團(tuán)聚體是土壤碳氮微生物轉(zhuǎn)化的重要場所,對維持土壤肥力具有重要作用。增施秸稈雖然沒有增加肥料~(15)N在土壤中的截留,但氮肥配施秸稈使更多的肥料氮進(jìn)入53μm的團(tuán)聚體中,促進(jìn)了土壤和團(tuán)聚體微生物對無機(jī)肥料氮的固持,長期來看,這有利于肥料氮的固持和逐漸礦化被農(nóng)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.
【學(xué)位授予單位】：沈陽農(nóng)業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：S158
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本文編號：1802178