Study on characteristics of nitrogen from slow-release compound fertilizers using alkali-hydrolyzed reduction diffusing method

In this study, SRCFs developed and produced by ourselves were employed to investigate the N release process using continuous alkali-hydrolyzed reduction diffusing method. The results showed: 1）When absorbing solution was H3BO3, the N accumulated diffusing rate of SRCF increased with the increasing content of NaOH (0-0.1 mol/L). In the meantime, it was higher than that of 0.5-2 mol/L NaOH. 2）Under the same content of NaOH, the N accumulated diffusing rate of SRCF was greater in 0.1mol/L H2SO4 than in 0.1 mol/L H3BO3. 3）When NaOH was used in 0.05 mol/L or 0.1 mol/L, the N diffusing character of SRCF were similar to the N mineralization process of SRCF cultured by means of the soil-fertilizer-packet method. Thus, the ideal operation conditions of continuous alkali-hydrolyzed reduction diffusing method were 0.05-0.1 mol/L NaOH (diffusing solution), 0.1mol/L H2SO4 (absorbing solution), continuously cultured for 40 days at 25℃ and titrated the absorbing solution in different periods.