SOLUBILITY OF SELECTED INORGANIC FERTILIZERS IN BRACKISH-WATER

Diammonium phosphate, monoammonium phosphate, triple superphosphate, a nd urea were dropped through a I-m column of water which ranged from 0 to 40 ppt salinity. Mean solubility of nitrogen was 4.1% from diammon ium phosphate, 11.8% from monoammonium phosphate, and 76.8% from urea. Mean solubility of phosphorus was 4.6% from diammonium phosphate, 10. 4% from monoammonium phosphate and 4.4% from triple superphosphate. Sa linity did not significantly affect the solubility of nitrogen and pho sphorus from diammonium phosphate. Nitrogen solubility from monoammoni um phosphate and phosphorus solubility from triple superphosphate sign ificantly decreased with increasing salinity, but the correlations wer e low. Urea solubility, and phosphorus solubility from monoammonium ph osphate responded curvalinearly to increasing salinity. Solubility dif ferences caused by salinity disappeared after 24 h of contact with wat er when all fertilizers dissolved completely regardless of salinity. N o adjustment for salinity is necessary when fertilizer rates are calcu lated for brackish water or marine application.