Effect and mechanism of organic-inorganic compound fertilization on chemical fertilizer utilization I.Effect of urea compounded with organic material on maize yield and fertilizer utilization

In this study,an organic-inorganic compound N fertilizer was processed by combining organic waste material(from monosodium glutamate factory) with urea,and the potted plants experiments(setting up three input rates of urea-N) were carried out to investigate effects of the organic-inorganic compound N fertilizer on crop yield,nutrient uptake,nutrient use efficiency of maize under the same urea-N application rate.The results show that compared to the urea treatment,maize grain yields are increased by 12.4%,4.8% and 5.4%,respectively under the low,medium and high N application rates.Under the same urea N application rate,the relative increases of maize grain yield of the organic-inorganic compound N fertilizer treatments to those of the corresponding organic material treatments are greater than those of the inorganic N fertilizer treatments and the no N fertilizer treatment.The organic-inorganic N fertilization increases uptakes of nutrients.At the low,medium and high urea-N application rates,N uptakes of maize plants are increased by 29.0%,21.6%,and 18.9% respectively under the organic-inorganic compound N fertilizer applications compared to the chemical fertilizer N treatments.The organic-inorganic N fertilizer applications increase urea-N use efficiency,and in the case of the same amount of urea N applied,the organic-inorganic compound N fertilizer applications increase N apparent recovery efficiencies by 11.6-33.5 percent compared to the urea treatments.