Effect of Biochar and Chemical Fertilizer Mixture on Ammonia Volatilization and Phosphorus Fixation

In order to explore biochar fertilizer addition, two types of industrial wastes (YM) and lees (JZ) and agricultural waste corn stover (JG) were used as the raw materials to make biochar, and the biochar was modified to make smoke-modified biochar (M-YM). The culture test method was used to study the law of ammonia volatilization and phosphorus fixation over a certain period of time with the different fertilizer ratios of the four biochars. We aimed to provide a scientific basis for the agricultural utilization of biochar. The results show that:① The cumulative volatilization and volatilization rate of ammonia of the four kinds of biochar with different fertilizer ratios were as follows:A1 > A2 > A3 (A1:2.25 g urea; A2:2.25g urea +2.25 g chlorination potassium; A3:2.25 g urea +2.25 g potassium dihydrogen phosphate). The addition of potassium chloride and potassium dihydrogen phosphate in urea reduced ammonia volatilization, and the cumulative ammonia volatilization and volatilization rate of different biochars under all chemical fertilizer ratios was JZ > M-YM > YM > JG; ② The amount of phosphorus by biochars fixation under the B1, B2, and B3 treatments (B1:0.4 g potassium dihydrogen phosphate; B2:0.4 g potassium dihydrogen phosphate +0.3 g urea; B3:0.4 g potassium dihydrogen phosphate +0.3 g potassium chloride) all increased and then decreased. Then, the fixation amount of phosphorus not significantly changed in period from 30th to 60th day. Among four biochar, the fixation rate of phosphorus was the highest under the B1 treatment.With the ratios of B1, B2, and B3 fertilizers, the order of the fixation rate of the four biochars to phosphorus was:M-YM > YM > JG > JZ. Therefore, in order to reduce the volatilization of ammonia in nitrogen fertilizers in agricultural fertilization, potassium chloride and potassium dihydrogen phosphate can be added to urea. At the same time, in the fixation of phosphorus, increasing the particle size of biochar may weaken the phosphorous fixation ability.