In Hexi irrigation area of Gansu Province managed for eight year corn seed production

field test method was used to study the relationships among soil improved special fertilizer

physical properties of seed production cornfield and corn economic traits and benefits. Results showed that the factors affecting corn production followed the order of CO(NH2)2>(NH4)2HPO4> PVA and ZnSO4·7H2O. Best combination for the factors is 30kg/hm 2 PVA

736kg/hm2 CO(NH2)2

420kg/hm2(NH4)2HPO4 and 52kg/hm2ZnSO47H2O. Withthe increases of soil improved specific fertilizer

corn field total porosity

capillary porosity

non-capillary porosity and aggregates increased

but bulk density decreased. When soil improved special fertilizer application increased

corn botanical traits

economic traits and yield increased

but yield increment by unit(1kg) amount of soil improved special fertilizer decreased gradually withthe increase of soil improved special fertilizer

showing the law of diminishing return. Withthe increased amount of soil improved special fertilizer

marginal corn yield and profit in the reduced profit margins. The additional 337.50kg/hm2 application rate over the 1350kg/hm2 soil improved special fertilizer made revenue to be negative. The optimum economic fertilization capacity was 1350.01kg/hm2 and theoretical corn yield was 6700.99kg/hm2.