水分和氮肥相互作用对水旱轮作体系氮素转化的影响

发布时间：2018-03-09 10:54

本文选题：氮肥用量　切入点：土壤质地　出处：《华中农业大学》2016年硕士论文　论文类型：学位论文

【摘要】：长江流域是我国重要的粮食产地,其中水旱轮作是该地区重要的轮作制度。常年的水旱轮作、不同的氮肥施用量以及土壤质地同影响农田土壤的氮素供应能力,进而影响着粮食的产量。本文通过田间定位实验和室内培养试验相结合的方式展开研究:在田间试验中,研究了不同轮作体系和施用氮肥对农田土壤全氮及有机氮库组分的影响;在室内培养试验中,模拟田间试验研究了不同轮作体系、氮肥施用以及土壤质地对土壤溶解性氮库、有机氮库及其相互转化的影响。通过对土壤氮素组分浓度的监测,该研究明确了在水旱轮作体系中氮肥施用后土壤有机氮组分的转化过程。试验结果如下:(1)田间试验数据表明,氮肥施用能显著提高土壤全氮含量。与初始土壤全氮含量相比,经过3年6季耕作后水稻-油菜和棉花-油菜两种轮作模式下土壤全氮含量分别增加了16.80%-24.97%和13.57%-23.50%。尽管两种轮作方式下土壤全氮含量并无显著差异,但水旱轮作体系土壤全氮储量的年增涨速率显著高于旱地轮作。氮肥和轮作方式对土壤有机氮库各组分的影响不同,氮肥施用显著增加土壤酸解铵态氮、氨基酸态氮以及酸解未知态氮的浓度;而相比旱地轮作,水旱轮作则显著增加土壤氨基糖态氮的浓度。(2)室内培养试验结果表明,氮肥施用能明显提高土壤无机氮浓度。在水旱轮作体系下,与不施氮处理相比,氮肥施用在水改旱处理中,土壤铵态氮先增加后降低,而硝态氮没有显著变化,而对土壤有机氮转化影响较小;在旱改水处理中,土壤铵态氮没有显著变化。与模拟旱地处理相比,会促进土壤有机氮向氨基糖态氮和酸解氨态氮转化。在不实施水旱轮作下(淹水或者旱地),与不施氮处理相比,模拟淹水处理氮肥施用增加了土壤酸解铵态氮和氨基糖态氮的浓度,施用的氮肥优先转化为酸解铵态氮,进而再转化为氨基糖态氮和酸解未知态氮;而模拟旱地处理氮肥施用会增加土壤氨基酸态氮浓度,氮肥施用则优先转化为氨基酸态氮,进而再转化为酸解未知态氮。(3)土壤质地的差异对不同水分条件下土壤氮素转化产生显著影响。砂土及粉砂质粘壤土酸解铵态氮浓度对氮肥的响应主要是受到水分影响。在淹水条件下,与不施氮处理相比,施用氮肥对粘壤土酸解铵提升最为显著。在旱改水处理下,氮肥施用显著降低砂土及粘壤土酸解铵态氮浓度。在旱地条件下,氮肥施用显著增加粘壤土氨基酸态氮浓度,而粉砂质粘壤土氨基酸态氮浓度降低了80 mg/kg-100 mg/kg,砂土降低了20 mg/kg-40 mg/kg。长期培养发现,氮肥施用后不同土壤氨基酸态氮均会降低,而酸解未知态氮浓度会进一步提高。
[Abstract]:The Yangtze River valley is an important grain producing area in China, in which the rotation of water and drought is an important rotation system in this area. Then the grain yield was affected. In this paper, the research was carried out by the combination of field location experiment and indoor culture experiment: in the field experiment, The effects of different rotation systems and application of nitrogen fertilizer on total nitrogen and organic nitrogen pool components in farmland soil were studied, and simulated field experiments were conducted to study the effects of different rotation systems, nitrogen application and soil texture on the dissolved nitrogen pool of soil. By monitoring the concentration of soil nitrogen components, the transformation process of soil organic nitrogen components after the application of nitrogen fertilizer in flood and drought rotation system was clarified. The results were as follows: 1) the field experiment data showed that, Compared with the initial soil total nitrogen content, nitrogen application could significantly increase soil total nitrogen content. After 3 years and 6 seasons tillage, the soil total nitrogen content increased by 16.80 -24.97% and 13.57-23.50%, respectively, under the two rotation patterns, although there was no significant difference in soil total nitrogen content between the two rotation modes. However, the annual increase rate of soil total nitrogen storage in paddy and dry cropping system was significantly higher than that in dryland rotation. The effects of nitrogen fertilizer and rotation on the components of soil organic nitrogen pool were different, and the application of nitrogen fertilizer significantly increased soil ammonium acidolysis nitrogen. The concentration of amino acid nitrogen and acidolysis unknown nitrogen, and the concentration of soil aminosaccharide nitrogen increased significantly compared with dryland rotation. Application of nitrogen fertilizer could obviously increase the concentration of inorganic nitrogen in soil. Compared with the treatment without nitrogen application, the ammonium nitrogen of soil increased first and then decreased, but no significant change of nitrate nitrogen was observed. But it has little effect on soil organic nitrogen transformation, and there is no significant change of soil ammonium nitrogen in dry water treatment, compared with simulated dry land treatment, It can promote the conversion of soil organic nitrogen to aminosaccharide nitrogen and acidifying ammonia nitrogen. In the absence of irrigation and drought rotation (flooding or dry land), compared with no nitrogen application, Simulated flooding treatment increased the concentration of ammonium and aminosaccharide nitrogen in soil, and the nitrogen fertilizer was first converted to ammonium acid nitrogen, and then to aminosaccharide nitrogen and unknown amino nitrogen. However, nitrogen fertilizer application in simulated dry land could increase the concentration of amino acid nitrogen in soil, and the nitrogen fertilizer would be preferentially converted to amino acid nitrogen. The difference of soil texture has a significant effect on soil nitrogen conversion under different water conditions. The response of the concentration of ammonium ammonium to nitrogen fertilizer in sandy soil and silty loam soil is mainly affected by water. Effects... Under flooded conditions, Compared with the treatment without nitrogen application, the application of nitrogen fertilizer had the most significant effect on the increase of ammonium acid in clay loam soil. Under dry water treatment, nitrogen fertilizer application significantly decreased the concentration of ammonium ammonium acid in sandy soil and clay loam soil. Under dry land condition, the concentration of ammonium acidolysis ammonium in sandy soil and clay loam was significantly decreased. Nitrogen fertilizer application significantly increased amino acid nitrogen concentration in clay loam soil, but decreased amino acid nitrogen concentration in silty clay loam soil by 80 mg/kg-100 mg / kg and sand soil by 20 mg/kg-40 mg / kg. However, the concentration of unknown nitrogen in acidolysis will be further increased.
【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S153.6;S344.17

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