Nitrogen Topdressing on Rhizosphere Soil Nitrogen Supplying Capacity of Greenhouse Tomato with Reclaimed Water Irrigation

Abstract：To discuss effects of different nitrogen topdressing on rhizosphere soil nitrogen supplying capacity of greenhouse tomato with reclaimed water irrigation,field experiments were carried on,and rhizosphere soil mineral nitrogen and total nitrogen,non-rhizosphere soil mineral nitrogen and total nitrogen,plant biomass and yields,apparent N loss and nitrogen supplying capacity of key growth stages of different treatments were measured and analyzed.The results indicated that rhizosphere soil mineral nitrogen content remained 55 mg/kg above of tomato key growth stage,and mineral nitrogen content differences between rhizosphere and non-rhizosphere soil were 10.47% to 12.63% of reduced 20% and 30% fertilizing quantity treatment,thus promoting non-rhizosphere mineral nitrogen to rhizosphere migrating,nitrogen use efficiency,crop nitrogen productivity and yield of reduced 20% and 30% fertilizing quantity treatment were significantly higher than conventional nitrogen topdressing treatment.Therefore,nitrogen topdressing in 189 to 216 kg/hm2 with reclaimed water irrigation,effectively reduced apparent N loss of 0 to 30 cm layer,which promoted the non-rhizosphere mineral nutrients to rhizosphere migrating,and ensured rhizosphere soil mineral supplying during key growth stages of tomato,the rhizosphere soil nitrogen supplying capacity,partial factor producitivity from applied N,yield of nitrogen topdressing in 189 to 216 kg/hm2 was significantly improved than conventional nitrogen treatment.