STUDY ON APPLYING PHOSPHOGYPSUM FOR INCREASINGN-FERTILIZER EFFICIENCY

This paper discribed the effect of phosphogypsum(PG) on N-fertilizer productivity and utilization rate by pot and field experiments. The PG was blended fully with urea or ammonium bicarbonate fertilizers before they were used. The main results showed: (1) When the PG was mixed with ammonium bicarbonate, the increase in N-fertilizer utilization rate ranged from 2.82% to 3.70%, the N-fertilizer productivity increased grain by 1.23 kg/kg (wheat), 1.85kg/kg (maize); (2)When the PG was added to urea, the increase in N-fertilizer utilization rate ranged from 6.23% to 8.82%, the productivity increased by 2.11kg/kg (wheat),1.14kg/kg(maize); (3) When the PG and urea were compounded into blending fertilizer, the utilization rate and productivity increased by 13.38%, 3.06kg grains/kg N (maize) respectively; (4) The increase in the yield of wheat ranged from 5.2% to 9.2%, the maize ranged from 5.5% to 8.6% because of adding PG to N-fertilizers; (5) Pot experirment also showed that owing to adding PG the plant recovery of N-fertilizer and N-accumulation increased.