Abstract In order to investigate the effects of sulfuric acid pretreatment on the chemical properties and ammonia volatilization of White Fungus Chaff, dilute sulfuric acid solution with different concentrations was used to preprocess wood ear bran. Changes of the chemical properties and ammonia volatilization during fermentation were analyzed. The experiment was conducted with four treatments, 0 (A0), 0.1 (A1), 0.3 (A2) and 0.5 (A3)mol/L of acidification treatment concentration, and 15 d fermentation of all. The results show that during the composting process, the highest temperature of A0 was 56 ℃ and maintained within 55-56 ℃ from the 5th to the 10th day; the high temperature period of A1 treatment was 8 days, and its highest temperature was 59 ℃; the highest temperature of A2 was 48 ℃; there was no significant temperature change in A3. At the end of composting, compared with pH value of A0 with no sulfuric acid addition (6.63), pH value of A1,A2 and A3 decreased by 1.37, 4.73 and 5.105, respectively, and EC value of A0, A1, A2 and A3 was 0.163, 0.278,0.415 and 0.603 mS/cm, respectively. Water content of A0, A1, A2 and A3 decreased by 42.73%, 43.07%, 33.72% and 22.00% compared with the initial stage. Organic matter content of A0, A1, A2 and A3 decreased by 5.55%, 8.59%, 12.91% and 2.15%, respectively. N content decreased first and then increased with the extension of the maturity time, which increased by 40.50%, 32.70%, 18.20% and 0, respectively. The trend of P and K content was basically the same, and A1 content had the largest increasing trend, which was 66.7% and 80%, respectively. A0 was in the second place, with an increase of 56.67% and 60%, respectively; A2 increased slightly, with an increase of 5% and 24%, respectively; In A3 treatment,phosphorus content decreased by 42.22% and potassium content increased by 12%, respectively. Ammonia volatilization accumulation of A0, A1, A2 and A3 was 1.01, 0.81, 0.18 and -0.11 g/( kg·h), respectively, and compared with A0, the loss of N in A1, A2 and A3 decreased by 72%, 96% and 113%, respectively, indicating that ammonia volatilization was significantly decreased after acid pretreatment, which accelerated the degradation of organic matter and the content of N, P and K increased. Sulfuric acid pretreatment can shorten composting period, improve compost quality and reduce N loss, and the treatment with 0.1 mol/L (A1) has the best effect.
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