Nitrogen Availability, Nitrification of Fractions from Commercial Ureaforms

Abstract

Three commercial ureaforms have been fractionated by use of the cold and hot water solubility procedures used in the activity index determination. Approximately equal fractions-cold water-soluble, cold water-insoluble but hot water-soluble, and hot water-insoluble-were nitrified at rapid, intermediate, and slow rates, respectively. Good agreement was obtained in comparing nitrification rates of these ureaforms with the values obtained by recombination of their fractions, showing that the fractions were not greatly changed by the fractionation procedure and had no significant effect on each other in nitrification. The effect of granule size on nitrification rate is much less for commercial ureaforms than for other insoluble nitrogen sources such as oxamide or magnesium ammonium phosphate. While affected by granule size to some extent, ureaforms show their characteristic nitrogen release pattern, even when finely divided.

Biodegradability of Ureaformaldehydes and Related Compounds

“…A comparison of the nitrification of the fractions of ureaform with similar fractions reported by Hays and coworkers (6) shows that agreement exists between the results of biodegradability studies and nitrification. Water-soluble nitrogen b.…”

“…The large water-insoluble portion of ureaforms is responsible for their useful slow release properties in comparison with the rapid release from soluble fertilizer materials. In the continuous series of methyleneurea polymers which make up a ureaform, the lowest polymers are the more soluble in water (6). The lowest member of this series, methylenediurea (NHoCONHCHo-NHCONH)), is 2.5% soluble in water at 25°C .…”

Soluble Fraction of Ureaforms-Nitrification, Leaching, and Burning Properties

“…activity index method (7). The procedure described previously (6) was adapted to a much larger scale preparation. Five pounds of Hercules Nitroform, ground to pass a 35-mesh screen, was slurried with 110 gallons of water at 25°C.…”

Ureaform as a Slow Release Fertilizer: A Review

“…degree of polymerization, whereas the granule size has no pronounced effect as in the case of other urea-aldehyde condensates (IBDU, etc.). (Hays et al, 1965;Jiirgens-Gschwind. 1974;Prusud et al, 1971).…”