Study on fertilizer efficiency and its mechanism of urea and ammonium bicarbonate treated with controlled-release technology

Coated and uncoated ammonium bicarbonate and urea were made by using modified industrial and agricultural waste materials and inorganic minerals Pot experiments,indoors leaching experiment and X ray diffraction were conducted to study the effect and the controlled release mechanism The results showed that both coated and uncoated controlled release fertilizer had higher fertilizer efficiency, and the N use efficiency was increased obviously Owing to the interaction between active group of organic controlled release materials and urea or ammonium bicarbonate, the crystal structure changed obviously and the crystallinity decreased For the tightly coated fertilizer, mixing with the faster releasing fertilizer to adjust the column balance of various nutrient release velocities was more effective to increase yield and fertilizer use efficiency Compared with coated fertilizer, the uncoated fertilizer cost less but had equal or higher fertilizer efficiency Both coated and uncoated controlled release fertilizers could raise the market competitiveness of urea and ammonium bicarbonate, showing a good prospect for industrialization