A series of laboratory and greenhouse experiments were conducted to
evaluate the compaction of metal salt urea with monocalcium phosphate (MCP) to
prepare urea-based fertilizers that contain monocalcium phosphate and still maintain
good physical properties during storage. Results revealed that minimizing the
hydrated water was observed from compacted metal salt urea with MCP. However a
slightly increase in the free water content for the urea + MCP; indicating the
replacement of the hydrated water of MCP. H20 by the urea. Data also showed that
the compacted metal salt urea with MCP resulted in a reduction of urea hydrolysis,
total inorganic nitrogen and NH3 volatilization than compacted urea with MCP during
the incubation periods. Results showed that the release of phosphours from different
products varied depending on some physical. chemical characteristics of the
materials. The reaction with MCP to form the adduct complexing metal salts with MCP
increase of these variation in the releaseable-P in the soil. The addition of compacted
metal salt urea with MCP at any ratio improved the characterization of metal salt urea
complexes comparing with other treatments. Results also showed that the availability
fraction of Fe and Mn in the treated soil with Fe(urea)s 504.MCP or Mn(urea)4504.
MCP, tended to increase as compared with compacted urea + MCP. This result may
be due to the formation of stable complexes with Fe and Mn. These process may
creat suitable condition to maintain both fractions in available forma through
increasing its solubility products. The addition of Fe(urea)6 504 or Mn(urea)4 504
without compaction with MCP the fresh and dry weight of shoot and root of radish
plant were significanUy increased as compared with urea compacted with MCP.
However the addition of compacted urea with MCP was a remarkable effect on root
and shoot of radish plant as compared with urea alone. It was noticed that the addition
of Fe (ureaj, 504 or Mn (urea), 504 enhanced the utilized of N, P, K. Fe and Mn
uptake through improving the management practices of nutrient supply. Whereas the
application of compacted Fe (urea)s 504 or Mn (urea)4 504 with MCP were more
pronounced effect on the N, p. K, Fe and Mn uptake. Generally. the use of compacted
metal salt urea complexing with MCP may offers some advantages such as, reduction
in urea hydrolysis andlor NH3 volatilization. improvement of seed germination and
supply of micronutrients to soils.