不同施肥模式对蔬菜地中氮素流失影响研究

发布时间：2018-01-14 06:05

本文关键词：不同施肥模式对蔬菜地中氮素流失影响研究　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：在点源污染已逐渐得到有效控制的今天,农业面源污染问题的严峻性日益凸显,而蔬菜地作为重要的土地利用方式之一,因其生长周期短、复种指数高和肥料施用量大等特点,导致由不合理施用氮肥造成的蔬菜地氮素面源污染问题相当严重。针对蔬菜地氮素面源污染造成的水体富营养化以及地下水硝酸盐污染问题,本研究从不同施肥模式入手,通过人工模拟降雨试验,以盆栽土培小白菜作为研究对象,探索四种不同施肥模式(不施肥、单施有机肥、化肥有机肥各半、单施化肥)对氮素径流流失、淋溶损失的特征以及氮肥利用率的影响。主要研究结果如下:(1)不同施肥模式对蔬菜地氮素径流流失的影响施肥是导致蔬菜地氮素径流流失的主要因素,化肥有机肥复混的施肥模式下氮素径流流失的风险最小,具有较高的环境效益。总氮和硝态氮浓度随时间总体呈递减的趋势,但氨氮的浓度则是波动减少的,施肥前期和作物生长初期的降雨引发氮素径流流失的风险极高。径流中各形态氮的浓度与降雨强度正相关。氮素径流流失的主要形式是颗粒态氮,而硝态氮是溶解性无机氮径流流失的主要形式。(2)不同施肥模式对蔬菜地氮素淋溶流失的影响化肥有机肥混施造成的土壤氮素淋溶流失程度相对较少。三种不同施肥模式的淋溶液总氮浓度和硝态氮浓度的变化趋势均是先升高达峰值后再降低,逐渐趋于平缓。氨氮淋失浓度随时间虽有波动但总体较为平缓。降雨强度和淋溶液中总氮、硝态氮、氨氮浓度成正相关关系,而且随着降雨强度增大,三种施肥模式的总氮和硝态氮淋溶液浓度的峰值提前出现。氮素绝大多数以硝态氮、氨氮等可溶性无机氮的形式向下淋溶,硝态氮是蔬菜地淋溶的主要氮素形态。(3)地表径流和淋溶液中氮素浓度的比较本试验条件下,降雨后引起的氮素面源污染的主要形式是淋溶损失,总氮、硝态氮和氨氮的地表径流浓度都小于淋溶液中的浓度。(4)不同施肥模式对氮肥利用率的影响各施肥模式都不同程度的促进小白菜植株中氮素的累积,化肥有机肥混施的处理小白菜植株累积的氮素最多,氮肥利用率(26.03%)最高,单施有机肥的小白菜氮素累积效果不如单施化肥。综上所述,在蔬菜种植的短期时间内,采用化肥有机肥混施的施肥模式能够在保障氮肥利用率较高的条件下,减少氮素的流失,从而降低氮素面源污染的风险,走上环境友好、安全高效和可持续发展的农业生产之路。
[Abstract]:In the point source pollution has been effectively controlled today, serious problems of agricultural non-point source pollution has become increasingly prominent, and the vegetable is one of the important ways of land use, because of its short growth cycle, the characteristics of higher multiple cropping index and fertilizer application amount is very large, leading to nitrogen caused by unreasonable application of nitrogen in vegetable sources the pollution problem is very serious. The eutrophication caused by non-point source pollution in vegetable and groundwater nitrate pollution problems, this research from different fertilization modes, through artificial rainfall simulation experiment, the pot of cabbage as the research object, explore four different fertilization modes (no fertilizer, organic fertilizer. Fertilizer and organic fertilizer were chemical fertilizer) on nitrogen runoff loss characteristics, leaching loss and influence of nitrogen use efficiency. The main results are as follows: (1) different fertilization patterns on vegetable n size Influence of flow loss is the main factor leading to fertilization in vegetable nitrogen runoff, organic fertilizer complex fertilizer fertilization mode under nitrogen runoff risk minimization, with higher environmental benefits. Total nitrogen and nitrate nitrogen concentration had a decreasing trend, but the concentration of ammonia nitrogen is less volatile, fertilization early and early crop growth of rainfall caused by nitrogen runoff and rainfall intensity. The high risk concentration of nitrogen in runoff are related. The main form of nitrogen runoff is particulate nitrogen, and nitrate nitrogen is the main form of dissolved inorganic nitrogen runoff loss. (2) different fertilization patterns on the impact of the loss vegetable nitrogen leaching of fertilizer organic fertilizer caused by soil nitrogen leaching loss is relatively less. The change trend of three kinds of different fertilization patterns of total nitrogen leaching solution concentration and nitrate concentration are rising first Up to a peak and then decreased gradually flatten. Leaching concentration of ammonia nitrogen with time although fluctuations, but overall is relatively gentle. Rainfall intensity and total nitrogen leaching solution, nitrate nitrogen, a positive correlation between the concentration of ammonia, and with the increase of rainfall intensity. The peak, three fertilization patterns of total nitrogen and nitrate nitrogen leaching solution the concentration of nitrogen appeared earlier. Most of the nitrate nitrogen, ammonia nitrogen and dissolved inorganic nitrogen in the form of downward leaching, nitrate nitrogen is the main form of nitrogen leaching in vegetable. (3) nitrogen concentration in surface runoff and leaching solution in the experimental conditions, the main form of non-point source pollution caused by rainfall. Is the leaching losses of total nitrogen, runoff concentration of nitrate nitrogen and ammonia nitrogen are less than the concentration of leaching solution. (4) different fertilization patterns on different fertilization patterns affect nitrogen use efficiency of different degree n in Pakchoi leaves. Product, nitrogen fertilizer organic fertilizer of cabbage plants accumulated most, nitrogen utilization rate (26.03%) the highest, single application of organic fertilizer nitrogen accumulation in Pakchoi effect than chemical fertilizer. In summary, in the short time of growing vegetables, using chemical fertilizer and organic fertilizer fertilization mode in nitrogen utilization conditions a higher rate of protection, reducing the loss of nitrogen, thereby reducing the risk of non-point source pollution, on environmental friendly, safe and efficient and sustainable development of agricultural production.

【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X52;X712

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