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Full-Text Articles in Physical Sciences and Mathematics

Using Urea Nitrogen As A Fertilizer, Kenneth L. Wells Dec 1984

Using Urea Nitrogen As A Fertilizer, Kenneth L. Wells

Soil Science News and Views

Solid granular or prilled urea (45-46% N) has become widely available in Kentucky, as has 28% nitrogen solution (UAN solution) which is half urea and half ammonium nitrate. When applied to a field, urea is transformed to ammonium N soon after application. The rate of transformation is greatly increased by urease, the enzyme found to varying degrees in soil and on plants and plant residues. Due to the chemical reactions involved as urea nitrogen undergoes transformation, there is some degree of likelihood for volatilization loss of some N. Whether such a loss will occur, and how much N will be …


Evaluation Of Nitrogen And Phosphorus Enrichment Using In Situ Enclosure Bags With Temporal Indigenous Phytoplankton Populations, Richard L. Meyer, W. Reed Green Sep 1984

Evaluation Of Nitrogen And Phosphorus Enrichment Using In Situ Enclosure Bags With Temporal Indigenous Phytoplankton Populations, Richard L. Meyer, W. Reed Green

Technical Reports

An in situ experimental procedure and protocol was developed to evaluate nitrate and phosphate enrichment using isolated indigenous phytoplankton assemblages during different seasons. Results of the comparison of the parameters-temperature, pH, alkalinity, conductivity, and dissolved oxygen between the open water and enclosed systems indicated that there was no significant influence of the physicochemical factors on the isolated biological processes. Growth responses were measured by turbidity, biomass and chlorophyll-a, the most sensitive being chlorophyll-a. Additions of nitrate and phosphate were added in known concentrations and in different magnitudes of concentration based upon ambient conditions and ratio. During the fall, phosphorus influenced …


Use Of Urea For Crop Production In Kentucky, Wilbur W. Frye Mar 1984

Use Of Urea For Crop Production In Kentucky, Wilbur W. Frye

Soil Science News and Views

Current trends indicate that urea will become the major source of solid and liquid N fertilizer in the future. Although urea has several advantages over other N fertilizers, especially in manufacturing, transporting, and marketing, there are some potential agronomic problems that farmers should keep in mind when using urea.