Effects Of Different Conditioners On Aerobic Composting Of Pig Manure And Their Application

Composting is an effective means for livestock manure recycling,and is essential to reduce the risk of environmental pollution.To study the effect of chemical conditioner on pig manure compost quality and its application effect,an aerobic composting was conducted for 35 days using four treatments.The chemical conditioner was prepared by mixing ferrous sulfate,humic acid sodium,and superphosphate(m:m:m=7:2:1).Four treatments were treated with different mass ratios of the fresh pig manure,including 0%(CK),1% conditioning agent(CA1),2% conditioning agent(CA2),and 3% conditioning agent(CA).The physical and chemical properties were measured and explored during composting process.Five treatments including no fertilization(T0),pure fertilizer(T1),1% conditioner-treated compost(T2),2% conditioner-treated compost(T3),and 3% conditioner-treated compost(T4)were treated with field experiment and mathematical statistics to study their effects on SOC,nutrients,enzyme activities,yield components and nutrient absorption of rice and provide a scientific basis for the utilization of livestock manure in Chengdu plain.The main results are as follows:(1)Adding conditioning agent could accelerate start-up speed and maturity process,improve the nutrient content of pig manure composting products,reduce nitrogen loss during composting and eliminate the toxic effect of pig manure on plant growth.The results gradually increased with the raise of conditioning agent amount,and their highest concentrations in the CA3 treatment.At the end of composting,the total P,total K,available P and available K concentrations in CA3 treatment were 1.5%-8.3%,0.6%-4.1%,2.1%-9.6% and 0.9%-9.9% higher than that of other treatments,respectively.Its total amount of ammonia volatiles was 42.5% lower than that of CK,and the total N and organic N concentrations were 16.9% and 13.8% higher than that of CK,respectively.The N fixation rate in CA3 treatment was 2.15 times and 1.74 times higher than that of CA1 and CA2,respectively.Moreover,the seed germination index was as high as 85.7% in CA3 treatment.(2)The application of pig manure composting was beneficial to the positive accumulation of SOC,which can promote the increase of soil nutrient contents and enzyme activities.The concentrations of total P,available N,available P and available K in three pig manure composting were significantly higher than those of T0 treatment by 8.5%-17.1%?11.4%-19.5%?6.2%-10.7% and 20.4%-39.5%(P <0.05),and their highest concentrations were in the T4 treatment.The activities of catalase,sucrase and neutral phosphatase in the T4 were significantly higher than those of T0 and T1(P <0.05),which were 1.01-1.05 times,1.01-1.053 times,1.09-1.13 times,and 1.03-1.08 times of T0 treatment,1.05-1.10 times,1.07-1.09 times,1.08-1.12 times and 1.10-1.15 times of T1 treatment,respectively.(3)Different fertilization treatments could significantly affect the rice yield and its composition,the uptake of N,P and K by rice plants.The rice effective panicles,grain number per panicle in three pig manure composting were significantly higher than those of T0 treatment(P <0.05).The rice yield of three pig manure composting were 43.4%-65.2% and 5.5%-21.5% higher than those of T0 and T1,respectively,and the uptake of N,P and K in plant of three pig manure composting were also significantly higher than that in T0 and T1(P <0.05).Among them,T4 showed the highest.Therefore,adding chemical conditioning agent could effectively reduce ammonia volatilizations and nitrogen loss,and improve the composting efficiency of pig manure.Moreover,the composting products could significantly improve soil nutrient concentrations,soil biological characteristics,and promote rice yield and quality improvement.Among them,T4 showed the best.