Nitrogen transformations during hydrolysis and nitrification of urea

Nitrogen transformations occurring in ten soils fertilized with urea were determined during incubation in the laboratory for four weeks. Urea was applied at one rate, but with different placement methods. Urea was applied in solution, as prills with a 1 cm grid spacing and as prills with no spacing. Unfertilized soils and soils amended with KNO₃ solution were included as controls.Nitrite accumulated in the majority of soils treated with urea, and the maximum nitrite concentration measured was directly related to initial soil pH. Cumulative gaseous N losses as percentages of applied N were: NH₃, 0-59.6; N₂, 0-4.9; N₂O, 0-9.9; KMnO₄-N, 0-1.3; CH₃ONO, 0-<0.1. No gaseous N evolution was detected in control treatments. Gaseous N losses were correlated with soil pH (NH₃) maximum NO ₂ ^- concentration (N₂, N₂O, KMnO₄-N) and organic C content (N₂, N₂O). Fertilizer placement effects were generally not significant and were small in comparison with differences between soils.

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Resumo Foram determinadas, durante incubação em laboratório por quatro semanas, as transformações do nitrogênio ocorridas em dez solos fertilizados com uréia. A uréia foi aplicada a um só nivel, mas com diferentes métodos de aplicação: em solução e em grânulos com 1 cm de espaçamento de grade e em grânulos sem espaçamento. Solos não fertilizados e solos corrigidos com solução de KNO₃ foram incluidos como controles.O nitrito acumulado na maioria dos solos tratados com uréia e a concentração máxima de nitrito medido foram diretamente relacionados ao pH inicial do solo. As perdas cumulativas de N gasoso tomadas em percentagens de N aplicado foram: NH₃, 0-59.6; N₂, 0-4.9; N₂O; 0-9.9; KMnO₄-N, 0-1.3; CH₃ONO, 0-<0.1. Não foi detectada liberação de N gasoso nos tratamentos de controle. As perdas de N gasoso foram relacionadas com o pH do solo (NH₃), concentração máxima de NO ₂ ^- (N₂, N₂O, KMnO₄-N) e teor de C orgânico (N₂, N₂O). Efeitos da aplicação de fertilizante não foram de um modo geral significativos e foram pequenos em comparação com as diferenças entre os solos.

     

蓬勃发展的中国磷肥工业如何面对磷矿资源瓶颈

近10年来,我国磷肥工业取得了突飞猛进的发展,其主要标志是以基础肥料磷酸二铵（DAP）为代表的高浓度磷复肥从无到有、从小到大,生产装备的技术水平和国产化程度快速提高,产品结构不断优化,自给率不断提高。但在高速发展的同时,风险和隐忧已经显现,即DAP市场可能出现严重的供过于求、原料磷矿供不应求、磷矿资源衰竭速度加快,这直接威胁我国中、远期的粮食安全。为此,笔者建议采取坚决禁止磷矿石的出口、鼓励进口磷矿石、限制磷铵的发展速度、继续坚定不移地实行“矿肥基地”和“酸肥基地”并举和并重的方针、大力提倡两大基地的资源整合和鼓励有条件的“酸肥基地”企业参与开发矿山等措施,切实保障我国磷复肥工业的可持续发展。     

The roles of nitrogen,phosphorus and Potassium in the production of sugarcane in South Africa

The amounts of N and K fertilizers used in the South African sugar industry have increased dramatically in the past four decades, due partly to an increase in the area under sugarcane but also to large increases in the amounts of N and K fertilizers applied per hectare. There has also been an increase in the amount of P fertilizer used but this has been more gradual. The main fertilizer carriers for cane and their relative efficiency are discussed. During this period there has been considerable research into the nutrient requirements of sugarcane. Correlations established between soil and leaf analysis and crop responses to N, P and K fertilizers, and their effects on cane quality, are reviewed. While fertilizer recommendations based on soil and leaf analysis have provided a useful guide for determining the nutrient requirements of cane, they are continually being modified in the light of current research.     

Outlook on fertilizer use efficiency in the tropics

In this paper efficiency of applied fertilizers under tropical conditions is examined. Understanding of the fertilizer efficiency is particularly important for the developing countries mainly because there is need for enhancement of crop yields at a reduced cost. Many of the soil, plant and climatic factors of the tropical regions that contribute to the efficiency of the applied fertilizers have been discussed. Many of the tropical soils are acidic in nature and in these soils efficiency of applied fertilizer is relatively poor, mainly because plant roots are unable to grow and function to their fullest extent in utilizing the soils available nutrients. To enhance yield potentials there is need for understanding of interaction between crop species and soil and climatic variables. Incorporation and adoptation of a suitable application time can greatly enhance efficiency of urea form of nitrogen. Research findings in tropical soils have shown that an initial broadcast application of P and subsequent band treatment is more effective than either method of application alone. Current crop yields in tropical countries are far below the known yield potentials. Such low production potentials are attributed to the lack of suitable crop germplasms and understanding of improved agronomic practices. Intensification of research activities in fertilizer use efficiency in tropical countries is suggested.Senior author formerly was a Research Advisor to EMBRAPA/IICA/World Bank Program in Brazil.     

Application of a rice field experimental error distribution function to nitrogen-phosphorus-potassium fertilizer response model analysis

A distribution function of rice yield deviations from the mean was developed from field experiments with 555 plots at 16 sites in Zhejiang province, China, for three years. The deviation distribution in interval of 50kg/ha appeared as a symmetrical distribution with a high peak (Mean=0.279 [kg/ha], SD=240.686 [kg/ha]). Normality test using Kolmogrove-Smirnov test between the observed cumulative distribution and the normal cumulative distribution function indicates that the observed deviation distribution is not normal. An empirical exponential cumulative distribution function was developed. The distribution function was used to remove outliers during the development of a rice yield fertilizer response model, based on data from a non-replicated NPK field experiment.     

硝酸磷肥中有效钙的提取与测定

对经特殊工艺试制的硝酸磷肥中总钙进行测定。用中性柠檬酸铵提取、草酸沉淀、高锰酸钾滴定 ,提取率达 88.3 %～ 91.7% ,测定值的标准偏差为 0 .11,回收率为 98.4%～ 10 1.9%。     

如何撰写肥料发明专利申请文件 第八讲 用废物、废料制造肥料申请文件的撰写

这一讲着重介绍了用废物、废料制造肥料的专利申请文件撰写中的几个问题。     

化肥行业走新型工业化道路的思考

2 0 0 2年我国化肥产量达 3 0 70万t,化肥消费量约 4 0 60万t,国产化肥占 80 %。预测我国化肥的需求量 2 0 0 5年为4 60 0万t,2 0 1 0年为 5 1 0 0万t,2 0 2 0年为 5 60 0万t。指出了目前我国化肥行业存在的问题 ,提出了关于总体发展目标和国家应采取的政策。     

颗粒硫酸钾生产新工艺

介绍了硫酸钾肥料的施用现状，以及本工艺的主要原料、过程、特点和对农业生产的重要意义。给出了在曼海姆工艺基础上生产颗粒硫酸钾的温度、压力、活性物质添加量等条件。该工艺的最大特点是生产出来的粉状硫酸钾含水分极少，一般质量分数小于0．1％。     

关于高氮尿素磷肥工艺的试验研究

介绍一种用尿素生产高氮磷肥的新工艺 ,分析该工艺的技术参数和影响因素。新工艺克服了过磷酸钙和尿素直接相混时会释放出结晶水的局限性 ,所得产品不仅可以作为复肥生产的原料 ,而且可以直接喷浆造粒生产NP复肥 ,因而具有良好的实用性