我国需增加硝基肥产量,提升硝态氮施肥比例

论述了近年国内外生产和施用的氮肥中所含铵态氮和硝态氮的比例关系。硝态氮肥产量占全球氮肥总产量:世界约14%,欧盟约40%,而我国仅占2%。消费结构比例与产量比例相近。世界最大3家氮肥生产商Yara、Terra和PCS的主要产品为硝铵尿素溶液、硝酸盐等含硝态氮产品,产量和销售量占其氮肥总量的50%以上。加快发展我国硝基肥产业,提高硝态氮肥施用量,对优化我国施肥结构、提高肥料利用率有重要意义。     

发展“干法”硝尿磷肥正当时

近年来,我国氮肥产业快速发展,氮肥总产量2010年已达4 521万t(折纯);但铵态氮和硝态氮两种形式氮肥的发展却极不平衡,其中绝大多数是含酰胺态氮(尿素)和铵态氮(碳铵、氯化铵等)肥料,占氮肥总产量的95%以上,含硝态氮的氮肥不足5%(国外一般为10%,欧盟达40%),且仅有硝铵和硝酸磷肥两个品种(前者按国务院国发(2002)52号文件已不能直接作化肥使用),造成硝态氮和铵态氮两种含氮肥料比例失调,结构很不合理。     

高塔多形态氮素蔬菜专用肥的研制

在制造高塔尿基复合肥的基础上,通过合理搭配原料及添加中微量元素,研发了一种含硝态氮、铵态氮、酰胺态氮等多形态氮素蔬菜专用肥.介绍了蔬菜专用肥的工艺流程、技术指标和配方,并有效解决产品吸潮问题.大白菜种植试验表明,该肥氮肥利用率提高9.3百分点,白菜的营养品质明显改善.     

肥料中硝态氮、铵态氮、总氮的研究

研究仅含硝态氮、铵态氮的肥料,结果表明,用GB/T8572-2010《复混肥料中总氮含量的测定蒸馏后滴定法》检测含有硝态氮、铵态氮的肥料中铵态氮含量、硝态氮含量(差减法总氮含量-铵态氮含量=硝态氮含量)(标准GB/T8572-2010《复混肥料中总氮含量的测定蒸馏后滴定法》中没有体现总氮含量-铵态氮含量=硝态氮含量,这是根据铵态氮与硝态氮性质总结研究出来的)与标准NY/T1116-2014《肥料硝态氮、铵态氮、酰胺态氮含量的测定》单独检测铵态氮含量、硝态氮含量结果无显著性差异。GB/T8572-2010检测总氮含量与SN/T0736.5-2010《进出口化肥检验方法第5部分:氮含量的测定》检测总氮含量无显著性差异。     

硝态氮浓度对短程反硝化的反硝化速率影响研究

短程反硝化的反硝化过程是将水中的硝态氮反硝化控制在亚硝态氮阶段,亚硝态氮被直接还原成氮气的过程。硝态氮是亚硝态氮积累的来源,是影响短程反硝化过程的重要因素。通过改变硝态氮浓度,研究了不同浓度条件下的亚硝态氮的积累率,以及以短程反硝化的反硝化速率。结果表明,随着硝态氮浓度增加,亚硝态氮积累率先增大后趋于稳定,反硝化速率先增大再降低后趋于稳定,硝态氮浓度影响亚硝酸根积累率从而影响反硝化速率。实验采用双Monod方程模拟其反硝化过程动力学,根据方程可以预判不同硝态氮浓度下的反硝化速率。     

不同浓度亚硝态氮在弱碱性土壤中的转化规律研究

选取陕西省华县耕作土壤,在实验室条件下研究该弱碱性土壤在不同初始浓度的亚硝态氮(11.2,56,112,280,560 mg/kg土)存在下的氮的转化规律,并进一步阐明亚硝态氮在该土壤中的累积效应。结果表明,土壤中的亚硝态氮的累积效应随着浓度的增大不断增强,即土壤中亚硝态氮转化为硝态氮的转化时间随着亚硝态氮的初始浓度的增加而增加。但是,高浓度的亚硝态氮(560 mg/kg)向硝态氮转化过程中,从第10 d开始,亚硝态氮的转化速率明显下降,低于初始浓度为280 mg/kg时的状态,反应受到强烈的抑制作用;当调整土壤的初始pH值时,该浓度下的抑制作用也几乎不被影响。因此,对出现高浓度亚硝态氮的地区环境需要引起重视,并及时采取一定的措施,以防止其对人类健康产生进一步的影响。     

不同浓度亚硝态氮在弱碱性土壤中的转化规律研究

选取陕西省华县耕作土壤,在实验室条件下研究该弱碱性土壤在不同初始浓度的亚硝态氮(11.2,56,112,280,560 mg/kg土)存在下的氮的转化规律,并进一步阐明亚硝态氮在该土壤中的累积效应。结果表明,土壤中的亚硝态氮的累积效应随着浓度的增大不断增强,即土壤中亚硝态氮转化为硝态氮的转化时间随着亚硝态氮的初始浓度的增加而增加。但是,高浓度的亚硝态氮(560 mg/kg)向硝态氮转化过程中,从第10 d开始,亚硝态氮的转化速率明显下降,低于初始浓度为280 mg/kg时的状态,反应受到强烈的抑制作用;当调整土壤的初始pH值时,该浓度下的抑制作用也几乎不被影响。因此,对出现高浓度亚硝态氮的地区环境需要引起重视,并及时采取一定的措施,以防止其对人类健康产生进一步的影响。     

化肥与无公害食品

目前无污染的安全、优质、营养类食品的名称众多 ,按农业行业标准 ,统称为无公害食品为宜。农业生产中的有机废弃物应当尽可能地循环利用 ,但经验证明 ,在农业本身封闭的系统中进行生产 ,作物产量难以大幅度提高 ,而且在市场经济的今天也是不可能的。在无公害食品生产中 ,不应该把有机肥与化肥对立起来 ,而应当配合使用。世界各主要化肥生产国的氮肥中 ,硝酸铵是主要品种。有些生产条件和作物 ,适宜施用硝态氮肥。我国进口的三元复混肥中的氮约有 1/ 2是硝态氮。而我国生产硝态氮十分有限 ,应适当发展。蔬菜 (主要是叶菜、根菜 )中硝态氮的高量积累有种种原因 ,主要是过量、单一施用氮肥和采收期离追肥期太近 ,应当改正。     

玉米优化施肥效应研究

高产田中对玉米施肥的研究表明：在不减少产量的前提下,增加P、K基施量,减少N追施量的优化施肥要比习惯施肥节约40％,氮肥利用率提高程度最高达44．30％,养分资源得到合理利用.除节约成本外,优化施肥还能使土壤硝态氮残留量减少,保护环境,实现耕地的可持续发展.     

肥料中氨态氮、硝态氮、尿素态氮含量的测定与比较

本文主要介绍了肥料中的氨态氮、硝态氮、尿素态氮含量测定的反应原理以及测定方法的比较。     

Use and efficiency of a liquid nitrogen fertilizer on grassland

Liquid nitrogen fertilizers are, per unit of N, generally cheaper than granulated ammonium nitrate because of lower production costs. Although very corrosive, the storage and handling of liquid nitrogen fertilizers does not usually present any problems. The applicability and efficiency of a commercial liquid nitrogen fertilizer (containing 39% N, half urea and half ammonium nitrate) on grassland was investigated in comparison with granulated ammonium nitrate (27% N). The liquid nitrogen fertilizer was applied on continuously grazed paddocks without any repercussions for animal health. No scorching was observed provided that certain measures were adopted while spraying the fertilizer: i.e. little dilution with water, use of low pressure and large droplets and application on dry grass in cloudy whether. In comparison with the granulated ammonium nitrate, the liquid nitrogen fertilizer was less efficient; dry matter yield and N-uptake of the grass treated with the liquid nitrogen fertilizer were 76% and 73% respectively of the dry matter yield and N-uptake of the grass treated with the granulated ammonium nitrate fertilizer.Fertilization, especially with nitrogen, represents the biggest single cost in grass production. Because liquid nitrogen fertilizers can be produced less expensively then granulated ones, their price per unit of N, delivered to the farmer, is also lower.Another advantage is that liquid fertilizers are easy to handle (despite being corrosive) and can be distributed uniformly over the field. The greatest advantage can be expected on the large grass areas of continuous grazing systems. Because of these benefits, an investigation was carried out to assess the potential use and efficiency of liquid nitrogen fetilizer in comparison with granulated ammonium nitrate nitrogen, from 1983 up to 1987. In 1983 and 1984, the grass quality, especially NH₃ and NO₃ concentration directly after spraying, and animal behaviour were assessed. From 1985 to 1987, the grass yield and nitrogen uptake were measured under mowing conditions.     

硝氯基复合（混）肥生产的安全性分析

概述了硝酸铵、氯化铵自身的安全性,分析了硝酸铵与氯化铵及其他无机肥料混合物的热稳定性、硝氯基复合（混）肥生产的安全性。分析结果表明：在硝酸铵系氮磷钾复合（混）肥生产过程中,在高温条件下,Cl-会促进硝酸铵分解,有机物、油类更是促进硝酸铵分解的重要因素;在生产中,尤其是硝酸铵溶解、熔融过程中,严禁混入有机物和油类,特别是在生产有机-无机复合（混）肥中,禁止用含有有机质的洗涤水溶解硝酸铵,在干燥过程中必须遵循“低温大风量”的操作原则,以防止硝酸铵分解而引发爆炸。     

Plant response to the management of fluid and solid N fertilizers applied to furrow-irrigated corn

The use of fluid fertilizers has increased in recent years. Plant response to field management practices of fluid and solid N fertilizers in furrow-irrigated field studies has not been well-documented. This research studied the response of corn (Zea mays L.) to several field management practices of fluid and solid N fertilizers applied at several rates. Corn grown with sidedressed applications of the fluid fertilizers, urea ammonium nitrate (UAN) and 18-0-0+7Ca, generally had higher grain yields, higher yield efficiencies, higher ear populations, larger seed size, more kernels per ear, and a higher ear leaf N concentration than corn grown with preplant broadcast treatments of urea, ammonium nitrate (AN), and UAN. In 1988, corn grown with 280 kg N ha^–1 of AN applied preplant broadcast had a lower grain yield, yield efficiency, kernels per ear, and ear leaf N concentration, while ear population and kernel size were unchanged, in comparison to split applications of UAN at 224 kg N ha^–1. In 1989, corn grown with three split applications of UAN at 280 kg N ha^–1 had a higher grain yield and produced more kernels per ear without affecting yield efficiency, ear population, kernel size, or ear leaf N concentration compared with treatments at the 224 kg N ha^–1 rate. Use of split, side-dressed N management practices in furrow-irrigated corn should eliminate the need to use excessive N rates while maintaining grain yields and other plant responses, resulting in more efficient N use than traditionally achieved.     

The comparative effect of a mixed urea,ammonium nitrate,ammonium sulphate granular formulation on the efficiency of N recovery by perennial ryegrass

The¹⁵N isotope was used to study the mode of action of individual nitrogen sources in a 30% urea:30% ammonium nitrate: 10% ammonium sulphate:30% filler (w/w) granular fertilizer for perennial ryegrass in a greenhouse pot experiment. The fertilizer consisted of two types of granules, one containing 80% urea and 20% filler and the second containing 48% ammonium nitrate (AN), 16% ammonium sulphate (AS) and 36% filler. In addition the effect of dolomite compared with silica as the filler was investigated on nitrogen recovery from the 30:30:10:30 formulation.Dolomite adversely affected the recovery of nitrate N from the system and evidence suggested that MgCO₃ was the active component. Granules containing dolomite resulted in a lower dry-matter yield than those containing silica, however the difference was not significant as nitrate contributed only 20% of the N in the formulation. AN gave the greatest DM yield and urea the lowest with AS being intermediate. The¹⁵N budget in shoots, roots and soil indicated that only 65% of the N from urea was recovered at the end of the experiment compared with 86% for AN and 91% for AS. The dry-matter yield of the 30:30:10:30 formulation using silica as the filler was intermediate between urea and AN; however, the apparent N recovery was significantly higher than expected from the sum of the individual components. The use of¹⁵N labelling indicated that using separate granules for ammonium N and urea the recovery of urea was improved by 11% in the triple N mixture when both AN and AS were present in the second granule compared to the recovery on its own. The enhanced recovery of urea appeared to be a function of AN and AS acting together as neither source in double combination with urea had any effect on urea N recovery.Urea enhanced the recovery of nitrate N by 10% but decreased the recovery of AS by 6% (in the 30:30:10:30 formulation) in comparison with the single sources on their own. The results indicate that interactions can occur between N sources even when they are physically separated by being in different granules.     

Fate of nitrogen applied in different fertilizers to the surface of a calcareous soil in Syria

¹⁵N-labelled ammonium sulphate or¹⁵N-labelled urea were each applied in solutionat a rate of 30 kg N ha^-1 to the surface of 20soil cores (52 mm internal diameter × 100 mm deep)located on a field experiment at the ICARDA station,Tel Hadya, Syria. Recovery of ¹⁵N-label in theammonium, nitrate, organic and/or urea-N pools in thesoil was measured on days 0, 1, 2, 5 and 13 afterapplication. Total recovery of ¹⁵N was initially100%, but by day 13 after application it had declinedto 51% with urea and 73% with ammonium sulphate.Ammonium nitrate labelled either as ammonium or asnitrate was also applied to the soil surface of 8other cores at the same time. ¹⁵N recovery in thefour soil N pools was measured only on day 12 afterapplication. Total recovery of ¹⁵N-label was 75%with labelled ammonium and 57% with labelled nitrate.Volatilization of ammonia from this calcareous soil(pH 8.1) is one probable mechanism of N loss fromammonium and urea fertilizers: with nitrate bothleaching beyond the base of the core (i.e. 100 mm) and denitrification were responsible for Nlosses. These large losses of N immediately afterapplication have implications for fertilizermanagement practices.     

Efficiency of urea and ammonium sulfate for wetland rice grown on an acid sulfate soil as affected by rate and time of application

A pot experiment was conducted in a greenhouse to assess the effect of rate and time of N application on yield and N uptake of wetland rice grown on a Rangsit acid sulfate soil (Sulfic Tropaquepts). Response of rice at N rates of 800, 1600 and 2400 mg N/pot (5 kg of soil) was compared between urea and ammonium sulfate when applied at two times: (i) full-rate basal at transplanting and (ii) one half at transplanting and one half at the PI stage. In addition, labelled¹⁵N sources were applied either at transplanting or at the PI stage to determine the nitrogen balance sheet in the soil/plant system.No significant difference in grain and straw yields between urea and ammonium sulfate at low rate was observed. At the higher N rates, urea produced higher yields than did ammonium sulfate regardless of timing. The highest yields were obtained when urea at the high N rate was applied either in a single dose or a split dose while lowest yields were observed particularly when ammonium sulfate at the same rate was applied. Split application of N fertilizer was shown to be no better than a single basal application. The occurrence of nutritional disorder, a symptom likely reflected by high concentration of Fe (II) in combination with soluble Al, was induced with high rate of ammonium sulfate.In terms of fertilizer N recovery by using¹⁵N-labelling, ammonium sulfate was more efficient than urea when both were applied at transplanting. In contrast, application at the PI stage resulted in higher utilization of urea than of ammonium sulfate. The recovery of labelled N in the soil was higher with urea than with ammonium sulfate when the two sources were applied at transplanting, while the opposite result was obtained when the same fertilizers were applied at the PI stage. The losses from urea and ammonium sulfate were not different when these fertilizers were applied at transplanting but loss from urea was higher than that from ammonium sulfate when both were applied at the PI stage.     

回收硝铵废液对第2吸收塔NOx排出量的影响

在硝铵生产中,中和、蒸发蒸汽中夹带有一定的硝铵和氨,当其冷凝后成为硝铵废液后直接排放,不仅造成物料流失而且污染环境。为了节能减排,首先将中和废液回收至吸收塔内作为吸收剂进行生产性试验,运行1年后效果明显。之后逐渐回收了全部的中和、蒸发废液,节约了资源并减少了排放,为公司带来巨大效益。但是在回收硝铵废液后,会使第2吸收塔出口NOx排出量相对增加,从而增加了后工序处理的难度。在确定了造成NOx排出量增加的主要因素后,从工艺上采取了相应的措施,减轻了回收硝铵废液后产生的不利影响。     

Nitrification and nitrate movement from ammonium sulphate and urea in sandy soils as affected by their previous applications

Two successive applications of urea and ammonium sulphate (AS) at varying intervals were given in two soils, one of which was salt affected. The nitrification and nitrate leaching after both the applications of fertilizers was studied. The nitrification of first application of AS was faster than urea on both soils. However, the nitrification rate of both fertilizers was slow in salt effected soil. The same trend of results was observed with second application of fertilizers. However, the nitrification of second application given within 6 weeks of the first application proceeded at a much faster rate than that of the first application. The amount of NO ₃ ^- that moved down with periodic water application was related with nitrification rate and the amount of fertilizer nitrified at the time of water application.