Effect and mechanism of organic-inorganic compound fertilization on chemical fertilizer utilizationI. 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 recoveries by 11.6-33.5 percent compared to the urea treatments.