Effects of Phosphate and Potassium Fertilizers on Water Absorbent and Nutrients Holding Ability of Water Retaining Agent

The interactions between different P,K fertilizers and Water Retaining Agents(WRAs) with different water absorbent rate(WAR) were studied by determining the WAR and the amount of fertilizers absorbed and fixed by WRAs.The results showed that all the four phosphate fertilizer and potassium fertilizers: monoammonium phosphate,super phosphate,potassium chloride and potassium sulfate,obviously decreased the WARs of the WRAs,and the WARs of the WRAs were markedly decreased with an increase in fertilizer concentration.The relationship was described by power function.The order of the effects of the fertilizers on WAR were potassium chloride potassium sulfate monoammonium phosphate super phosphate,and the four fertilizers had stronger influence on polyacrylic salt polymer than polyacrylic salt-polyacry lamide polymer.The WRAs,when swelled in water,absorbed and fixed the fertilizers dissolved in water.The amount of absorbed and fixed fertilizers differed with WRAs and fertilizer types and decreased at some fertilizer concentrations with a decrease in the WARs.