Nitrogen fertilizer use in Wisconsin as anhydrous ammonia, urea-ammonium nitrate solutions, and urea ranged from about 148,000 to 213, 000 tons of N during the 19952000 period (Terry and Kirby, 2001). This amount is similar to that used about 10 years earlier when 170,000 tons of N was used in 1984. However, a substantial materials shift has occurred since 1984 when about 56% of the N used as t...

This paper presents the most important issues relating to the infl uence of mineral fertilizers on both the natural environment and human and animal health. The physiological, environmental and economic impact of fertilizer production and application, resulted from a low assimilation of mineral components by crops, has been described. The research on the development and production of a large an...

A new controlled release fertilizer was developed by coating urea particles with bio-based polyurethane. Coating materials were synthesized from liquefied wheat straw, isocyanate, and castor oil. The effects of liquefied solvents, mass ratio of liquid to solid, size of wheat straw, and reaction time during liquefaction process on the nitrogen release rate of polyurethane-coated urea (PCU) were ...

Controlled release urea (CRU) has been widely adopted to increase nitrogen (N) use efficiency and maize production, but the impacts can range widely depending on water availability in the soil. In an experiment using Zhengdan 958 (a popular summer maize hybrid), three levels of water treatments (adequate water condition [W3], which maintained soil moisture at about 75% ± 5% of the soil's field ...

A new type of controlled release fertilizers coated with polyurea was prepared. The granulated urea was firstly changed into a liquid urea by heating as the coating liquid. By spraying uniformly the urea was coated with the polyurea synthesized by the reaction of isocyanates with a liquid urea. The effects of different modifiers on N release characteristics of polyurea-coated urea (PCU) were st...

Effect of different nitrogenous fertilizers on the growth and yield of three years old tea (Camellia sinensis L) plants was investigated at National Tea Research Institute, Shinkiari, (Mansehra) during 2005-06. The nitrogenous fertilizers used were ammonium sulphate, calcium ammonium nitrate, urea and nitrophos along with control receiving no fertilizer. All the nitrogenous fertilizers were app...

High-precision oxygen isotope analyses were carried out on dissolved phosphate extracted from discharge waters from three wastewater treatment plants (WTP) located in western France, as well as on the different phosphate-based fertilizers applied by farmers in the same region. Measured delta(18)O values of phosphate from chemical fertilizers range from 19.6 to 23.1 per thousand, while those of ...