过量施肥对土壤微生物群落结构的影响

发布时间：2018-05-28 00:48

  本文选题：氮肥 + 磷肥　； 参考：《沈阳农业大学》2017年硕士论文

【摘要】：过量施肥可导致土壤酸化、盐碱化的现象。特别是在设施生产中,长期大量施用化肥导致土壤中氮磷钾养分严重富积、土壤酸化、次生盐渍化。随种植年限的延长土传病害也越来越普遍,严重制约蔬菜生产的产量和品质。这些已经受到人们的广泛的关注,但是目前关于土壤的养分失衡、酸化、次生盐渍化对微生物群落结构的平衡及土传病害的的影响尚不十分清楚。本文采用室内模拟培养试验,排除作物的影响,研究土壤氮磷钾积累、酸化及次生盐渍化对土壤可培养微生物生长繁殖、群落结构平衡及土传病原菌的直接影响,研究结果可为合理施肥、预防土壤土传病害的发生提供理论依据。试验结果如下:(1)氮肥对土壤细菌、真菌和放线菌数量的影响都较为显著,其中施用高氮量对放线菌生长的抑制作用最大,其次是细菌。当施氮量大于N2处理时,放线菌生长就会受到抑制;在高施氮量下土壤可培养枯萎菌生长旺盛,数量快速增加。施氮肥改变土壤的微生物群落结构,当施氮量大于N2处理时,土壤中放线菌比例不断下降,枯萎菌所占比例快速上升,逐渐成为优势菌群。(2)土壤盐分和NH4+—N含量对土壤可培养细菌数量有直接的正影响,NO3-—N含量通过对盐分的影响对可培养细菌数量有间接的影响。电导率和NH4+—N含量对土壤可培养真菌数量产生直接正影响,影响大小:电导率NH4+—N含量。水溶性盐分含量对土壤可培养枯萎菌数量有较好的正直接影响,NO3-—N通过对水溶性盐分含量对土壤可培养枯萎菌数量产生间接影响。(3)磷肥施入后,对土壤可培养细菌、真菌和放线菌有相同的变化趋势,当施磷量大于P3处理时时,土壤中的细菌、真菌和放线菌数量的生长会受到抑制,但是致病真菌—枯萎菌数量依旧持续增加。施磷肥改变土壤微生物群落结构变化,当施磷量由P3增加到P4时,土壤放线菌比例快速降低,枯萎菌比例快速上升。(4)钾肥和磷肥对是土壤可培养微生物数量的影响是一致的,但是钾肥对其影响小于磷肥;随着施钾量的增加,土壤放线菌比例和枯萎菌比例并没有太大改变。(5)钾肥施入后,土壤可培养微生物与土壤pH呈显著负相关,与水溶性盐分含量呈显著负相关。土壤可培养细菌数量受电导率直接影响大于pH。土壤水溶性盐分含量和pH对土壤可培养真菌数量产生直接影响。水溶性盐分含量对土壤可培养放线菌数量直接影响。水溶性盐分含量和pH对土壤可培养枯萎菌产生直接影响。(6)氮磷钾配施对土壤可培养真菌,尤其是致病真菌—枯萎菌数量影响最大,其次是放线菌,对细菌数量影响最小。速效磷含量含量对土壤可培养细菌和放线菌数量都有较好的正直接影响,NH4+—N含量对其产生较好的负直接影响;速效磷含量对土壤可培养真菌数量有较好正直接影响,pH对其产生较好的负直接影响;NH4+—N和NO3-—N含量通过对pH的影响对其数量产生间接影响;电导率对土壤可培养枯萎菌数量产生较好的直接影响;而NO3-—N含量通过对电导率的影响对其数量产生较好的间接影响。
[Abstract]:Excessive fertilization can lead to the acidification and salinization of soil, especially in the production of facilities. Long term application of chemical fertilizer leads to the serious accumulation of nitrogen, phosphorus and potassium in the soil, soil acidification and secondary salinization. The soil borne diseases are becoming more and more common with the prolongation of planting years, which seriously restrict the yield and quality of vegetable production. These have been affected by people. However, the effects of soil nutrient imbalance, acidification and secondary salinization on the balance of microbial community structure and soil borne diseases are not very clear. In this paper, indoor simulated culture tests were used to eliminate the effects of crops and to study soil nitrogen, phosphorus and potassium accumulation, acidification and secondary salinization. Growth and reproduction, community structure balance and the direct effect of soil borne pathogens, the results can provide a theoretical basis for rational fertilization and prevention of soil soil borne diseases. The results are as follows: (1) the effects of nitrogen fertilizer on the number of soil bacteria, fungi and actinomycetes are more significant, and high nitrogen application has the most inhibitory effect on the growth of actinomycetes. The growth of actinomycetes will be inhibited when the amount of nitrogen is greater than N2 treatment. The growth of the actinomycetes will be inhibited when the amount of nitrogen is high. The soil can grow rapidly and the number of the bacteria can be rapidly increased. The application of nitrogen fertilizer to change the microbial community structure of the soil, when the nitrogen application is greater than the N2 treatment, the proportion of actinomycetes in the soil is decreasing and the proportion of the Fusarium wilt is fast. Rising and gradually becoming dominant bacteria groups. (2) soil salinity and NH4+ - N content have a direct positive effect on the number of cultivated soil bacteria. The content of NO3- - N has an indirect effect on the number of cultured bacteria. Electrical conductivity and NH4+ - N content have direct positive effects on the number of cultivated fungi in soil: electrical conductivity NH 4+ - N content. Water soluble salt content has a good direct effect on the number of cultivated wilt in soil. NO3- - N has an indirect effect on the number of cultivated Fusarium Wilt in soil by water soluble salt content. (3) after the application of phosphate fertilizer, the soil culture bacteria, fungi and actinomycetes have the same trend of change, when the amount of phosphorus is greater than the P3 treatment At present, the growth of bacteria, fungi and actinomycetes in the soil will be inhibited, but the number of pathogenic fungi and Fusarium wilt still continues to increase. Application of phosphate fertilizer changes soil microbial community structure, when the amount of phosphorus is increased from P3 to P4, the proportion of soil actinomycetes rapidly decreases, and the proportion of Fusarium wilt rapidly increases. (4) potassium and phosphate fertilizer are the same. The influence of soil cultivable microbes was consistent, but the effect of potash fertilizer was less than that of phosphate fertilizer. With the increase of potassium application, the proportion of Soil Actinomycetes and the proportion of Fusarium wilt did not change much. (5) after the application of potassium fertilizer, the soil cultivable microorganism was negatively correlated with soil pH, and was negatively correlated with the water soluble salt content. The number of cultivated bacteria was directly affected by the electrical conductivity of the soil and the water soluble salt content of pH. soil and the amount of pH had a direct effect on the number of cultivated fungi in the soil. Water soluble salt content had a direct effect on the number of cultivated actinomycetes in the soil. Water soluble salt content and pH had a direct effect on the cultivated wilt of soil. (6) the application of N, P, K and K to soil The number of cultivated fungi, especially the pathogenic fungi - Fusarium wilt, was the most affected, followed by the actinomycetes, which had the least influence on the number of bacteria. The content of available phosphorus had a good direct effect on the number of cultivated bacteria and actinomycetes in the soil, and the content of NH4+ - N had a good negative effect on it; the content of available phosphorus could be cultivated in the soil. The number of bacteria has a good direct effect, and pH has a better negative effect on it. The content of NH4+ N and NO3- N has an indirect effect on the quantity of pH, and the conductivity has a good direct effect on the number of cultivated wilt of soil, and the content of NO3- N has a better indirect shadow by the effect on the electrical conductivity. Ringing.
【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】：S154.3
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本文编号：1944536