April 1951 _.I
87 s
INDUSTRIAL AND ENGINEERING CHEMISTRY
4
SUMMARY
Correlations have been found between empirical solubility relationships of urea-formaldehyde reaction products and their nitrification characteristics which permit laboratory evaluation of the snitahility of such products for fertilizer use. The reaction hetween urea arid formaldehyde leading to fornxition of urea-form appears t o progress through iiiethylol urea G- 5 CY-22 formation t o increasingly more Dilute solution Concentrated solution complex polymethylene urea product product compounds. Neutralization of the reaction misture a t the 1.31 1.35 U/F proper stage largely inhibits 14.3 / 18.7 49.0/ 11.2 A/B,, % completion of the reaction to 38.5 38.0 Total N, % excessively insoluble materials Urea N, % 0.9 4.3 and stabilizes the product t,o s u b s e q u e n t heat treatment. Application of the procedures of solubility analysis to a tiilute and a concentrated solution product indicated that the Composition of the system, LHz0/ g sample solubility of the major portion of the nitrogen was in the Figure 6. Application of Solubility Analysis Procedure to Urea-Forms CY-22 and G-5 range equivalent to 4 t o 18 rng. of urea per liter. Vegetative esperiments have shown that properly prepared 80% of its nitrogen in the solubility range equivnlent to 14 to urea-form materials are superior as the sole source of fertilizer 18 mg. of urea per liter. nitrogen for turf t o more soluble and more rapidly available nitrogen fertilizers. Experiments also have given some indication PLANT GROWTH TESTS that the use of urea-form t o supply a portion of the fertilizer Greenhouse studies ( 1 , 8 ) with grasses have shown that the nitrogen may improve both the yield and quality of row crops. nitrogen in urea-form materials becomes available to the crop more slowly and more uniformly throughout the gron-ing season LITERATURE ClTED than that of conventional nitrogen fertilizers. This difference .kniiger, J\-, H., Clark, K. G., Lundstrom, F. O., and Blair, between the nitrogen availability patterns of the two types of A. E., A g r o n . J . , 43, 123-7 (1951). rlrmiger, W. H., Forbes, I., Jr., Wagner, R. E., and Lundstrom, materials for equivalent applications of nitrogen resulted in a F. O., I h d . , 40, 342-56 (1948). lower initial response to urea-form than t o st’andard nitrogen Clark, K. G., S e e , J. Y., and Love, K. S., ISD. ENG.CHEIr , sources, and in a relatively greater response t o urea-form during 40, 1178-83 (1948). the later stages of growth. T h e over-all upt,ake of nitrogen from Crone, G .I.,Jr., and Lynch, C. C., J . A m . Chem. SOC.,70, 3795-7 (1948). properly prepared urea-form materials equaled or exceeded that Fuller, IT. H., and Claik I
