【作者】 郝高建；

【导师】 赵先贵；

【作者基本信息】 陕西师范大学 ， 环境科学， 2005， 硕士

【摘要】 自20世纪80年代以来,伴随着资源与环境问题日益恶化,环境污染作为一个全球性的严重问题,已经引起了世界各国的重视。而其中由于化学肥料的污染引发的生态环境破坏和农产品污染等问题也日趋严重,已成为新阶段制约农业持续发展的瓶颈之一。因此对于控制氮肥淋溶污染,提高化学肥料的利用率,减少环境污染与控制方法的研究已经成为人们研究的重点和热点问题。 本研究分为模拟试验和田间试验两个部分。模拟试验主要模拟农田的基本情况,测定土壤淋溶液中氮的含量,采用半微量开氏法。试验方法是称取相同质量的尿素和不同质量的包膜材料,将包膜材料均匀地包裹在尿素颗粒的表面,将包裹后的包膜肥料施入模拟试验的土壤中,每隔24个小时用蒸馏水淋溶,收集淋溶液,用蒸馏滴定法滴定淋溶液,即加碱蒸馏,使氨释放出来,用硼酸溶液吸收,而后用标准酸滴定之。通过公式计算出淋溶液中N素的含量。目的主要测定缓释肥料的淋溶释放速度,以及比较不同质量比的缓释肥料的释放差异。 田间试验主要检验缓释肥料在农作物生长过程中的吸收利用状况。模拟试验供试土壤为关中平原典型耕作土壤娄土,地点位于西安市灞桥区新筑镇,供试作物为大青菜。 经过2004年3月——2005年3月的试验研究,对天然包膜材料粘土、木炭、腐殖质和红胶泥5种材料的选择比较,主要从延长尿素的淋溶时间进行了对比,并根据淋溶曲线进行了分析,从中选择出了粘土和红胶泥作为主要的研究对象。在化学物质的包膜材料中主要研究了硫磺、硼砂、石膏等3种,并与天然包膜材料进行了对比分析。 对不同质量比红胶泥包膜尿素、粘土包膜尿素、硫磺包膜尿素、硼砂包膜尿素、石膏包膜尿素等淋溶曲线的对比分析,不同质量比、不同包膜材料的淋溶变化曲线整体变化趋势相似,多数都呈现单峰状的变化趋势,在试验开始的大约1～15天这一阶段,淋溶液N浓度较高;而后随着淋溶时间的延长,淋溶液N浓度逐渐降低。根据对淋溶时间、经济成本等的对比,经过方差分析,找出了不同包裹材料的最佳质量比的搭配组合:红胶泥包膜尿素的质量比是5:7时最好,可以延长淋溶时间11天,减少氮素淋溶损失16.12%;粘土质量的多少对延长尿素的释放时间作用不大,效果不明显;石膏和尿素两者的最佳质量比是5:8时,可以延长淋溶时间8天,减少23.86%的氮素淋溶损失;硼砂和尿素的质量比是5:7可以延长淋溶时间30天,当对照尿素N素全部淋出时,减少16.58%的氮素淋出,是最优更多还原

【Abstract】 Since the 1980’s, following with the deterioration of resources and environmental question day by day, the environmental pollution has already caused the attention of the countries all over the world as a global serious problem. And the questions of the ecological environmental disruption and agricultural product pollution etc that caused by the pollution of the chemical fertilizer are also serious day by day, which has already become one of the restriction factors of agriculture sustainable development in the new stage. So controlling the nitrogen fertilizer eluviationing pollution, improving the utilization ratio of the chemical fertilizer, reducing environmental pollution and studying of controlling method have already become focal and important point that people study.The research of this text is divided into simulated test and field test. The simulated test mainly simulates the basic situation of the farmland, determines the content of nitrogen in soil drench solution, and adopts semi-micro Macro Kjeldahl method. The test method is to fetch the urea of the same quality and coated material of different quality first, make coating material parcel evenly the urea particle s’ surface, grant them into the soil, eluviate with the distilled water every 24 hours, collect the eluviationing solution, titrate the eluviationing solution with distillation titrimetric method, that is, add alkali distillation, make the ammonia release out, absorb with boric acid solution, then titrate it with standard acid. Through the formula the content of N can be calculated in the eluviationing solution. The purpose is to determine the speed of the eluviation and release, as well as the release difference of the different mass ratio fertilizer that releases more slowly.Field test mainly examines the absorption situation of the fertilizer that releases more slowly during the growth of the crops simulated test takes Leaching Loss of the Guanzhong plain of Shaanxi province as example. The test place lies in Ba Qiao district of Xi’an., the test crop is big green vegetables.Through the experimental study from October of 2004 to March of 2005, the compare of the five kinds of materials: natural coating materials, clay , charcoal, humus, red clay, the compare of the time that postpones the nitrogen eluviationing and the analyze of the eluviationing curve, the text chooses clay and red clay as the mainresearch object. Such three kinds of coating materials as main research sulfur, borax, gypsum, etc. are mainly studied in the coated material of chemical compounds, and are compared and analyzed with the natural coating material.The eluviationing curve changes trend of different mass ratio and different coated urea resemble and the majorities all present the variation tendency of the unimodal form through the eluviationing curve’s compare and analyze of different mass ratio coated urea: red clay, clay, sulfur, borax, gypsum. At the stage of about 1-15 days when the test begins, it is higher in density of N in the eluviationing solution; and then with the extension of eluviationing time, the density of N reduces gradually. According to the contrast of eluviationing time and economic cost ,etc. through analysis of variance, the best mass ratio of different coating material matching is found out: It is the best matching when the mass ratioof red clay membrane urea is 5:7,which can lengthen the eluviationing time for 11 days, reduce the nitrogen eluviationing loss by 16.12%; the amount of the clay quality has no use to lengthen the eluviationing time and the result is not obvious; when the quality ratio of urea and gypsum is 5:8,it can lengthen the eluviationing time for 8 days, reduce the nitrogen eluviationing loss by 23.86%;when the quality ratio of urea and gypsum is 5:7,it can lengthen the eluviationing time for 30 days, reduce the nitrogen eluviationing loss by 16.58% when the contrast urea N is all eluviated out ; it is the optimum matching association; When the quality ratio of the urea and the sulfur is 5:6, which is a optimum proportion ,it can lengthen the eluviationing time for 13 days , reduce the nitrogen eluviationing loss by 39.95%.Arranged by the order of the five coated materials’ eluviationing time, according to the longest one: Borax >Sulfur >Gypsum >Red clay>clay, it is obvious that chemistry materials are higher than natural materials. The increasing range of the production of the crop is found in the little district test of field: the districts of gypsum coated urea >the districts of red clay >the districts which are planted with urea experimental districts of blank. It is obvious that the coated urea after dealed with obviously improves on the fertilizer efficiency. Through the measure of the N content in the soil sample from the test district, it is found that the whole nitrogen amount in the parcel fertilizer after dealed with is high 1.68-2.45 times than those which is not dealed with, this shows that the urea that is dealed with bag membrane can lengthen the fertilizer efficiency.This text is supported by natural science fund project in Shaanxi Province, and combine with actual conditions of China, choose from the coated material which is更多还原