Preparation of chicken litter biochar and its improvement of selenium-cadmium associated acidic soil
In order to explore the efficient preparation of chicken litter biochar(JF-BC)and its effects on the improvement of selenium-cadmium associated acidic soil in Enshi area,the temperature and time parameters of oxygen limited pyrolysis technology were optimized to prepare chicken manure biochar with high adsorption performance.A 52 days soil incubation experiment was conducted to explore the effects on chemical properties of soil with different addition of JF-BC(no addition was referred to CK,2%addition was referred to 2%BC,4%addition was referred to 4%BC).The experimental results showed that JF-BC showed the highest pH value and cadmium adsorption capacity which was prepared at 700℃for 1.5 h.The product had a stable adsorption effect on Cd2+solution of 4≤pH≤8,and the adsorption capacity was 244.81-248.22 mg·g-1.The incubated soil was improved from acidic to neutral or weakly alkaline by 2%BC and 4%BC.At the 3rd day,the contents of organic matter,available phosphorus and available potassium of 2%BC and 4%BC were significantly increased by 29.19%and 56.90%,425.4%and 449.09%,884.11%and 1475.82%,respectively,compared with CK.The effect was stable and sustained in incubation.The alkali-hydrolyzed nitrogen in 2%BC was significantly higher than that in CK,but there was no significant difference between 4%BC and CK.On the 52nd day of culture,the cation exchange capacity of 4%BC soil was significantly increased by 45.34%,compared with CK.During the incubated process,the soil available cadmium were decreased gradually in 2%BC and 4%BC,and the maximum decrease was 32.32%,while the effective selenium increased in 4%BC,and the maximum increase was 26.47%,compared with CK.JF-BC could effectively improve the pH,organic matter,cation exchange capacity of acidic soil in Enshi area,improve the soil phosphorus and potassium fertility,reduce the availability of cadmium,and improve the activation rate of selenium.The 4%addition showed a better improvement.However,when JF-BC was applied in large quantities,attention should be paid to the addition of nitrogen and the reduction of phosphorus and potassium.This study provideed useful exploration for improving soil acidification,increasing the utilization rate of selenium and inhibiting the migration and transformation of cadmium in Enshi area.
chickenbiochar litteracidic soilselenium-cadmium associationchemical properties of soil
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