不同热解温度茶渣生物质炭对茶园土壤吸附解吸NH4-N的影响

生物质炭对铵根的吸附解吸影响着土壤的固氮效果,为探讨茶渣生物质炭对茶园土吸附—解吸NH_4~+—N性能的影响,减少土壤中氮素的淋失,提高氮素利用效率,通过模拟培养试验,采用平衡吸附法及HCL解吸法,研究了不同热解温度下制备的茶渣生物质炭在不同添加比例(0.35%,0.70%,1.40%,2.80%)下,茶园土对NH_4~+—N吸附解吸的特性。结果表明:施用生物质炭能有效增强茶园土对NH_4~+—N的吸附,并随生物质炭添加量的增加而增强。同一生物质炭添加量下,4种生物质炭处理下茶园土对NH_4~+—N的吸附量大小表现为BC400BC300BC500BC600。生物质炭的CEC含量是影响土壤吸附NH_4~+—N能力的主要因素。土壤对NH_4~+—N的吸附过程均以Langmuir方程拟合达到显著水平(0.953 7R~20.995 5),以单层吸附为主。施用生物质炭后,土壤产生了解吸滞后,有效降低了茶园土对NH_4~+—N的解吸率,BC400的解吸率最低。茶渣生物质炭能够增强土壤对NH_4~+—N的吸附,降低对NH_4~+—N的解吸,有利于提高土壤对氮素的吸持能力,其中BC400,2.80%处理下效果最佳。

Effect of NH4+-N Adsorption-desorption by Tea Residue Biochar Prepared at Different Pyrolysis Temperatures in Tea Plantation Soil

The adsorption and desorption of ammonium by biochar affects the nitrogen fixation effect of soil. To explore the effect of tea residue biochar on the adsorption-desorption of NH₄⁺-N in tea garden soil, reduce nitrogen leaching in soil, and improve nitrogen use efficiency, through a simulated culture experiment, the equilibrium adsorption method and HCL desorption method were used to study the adsorption-desorption of NH₄⁺-N characteristics in tea garden soil in which the biochar that prepared at different pyrolysis temperatures was differently added (0.35%, 0.70%, 1.40%, 2.80%). The results showed that the application of biochar could effectively enhance the adsorption of NH₄⁺-N by tea garden soil and the enhancement increase with the increase of biochar addition. Under the same addition, the adsorption amount of NH₄⁺-N in the tea garden soil treated by four kinds of biochar trended as BC400 > BC300 > BC500 > BC600. The CEC content of biomass carbon was the main factor affecting the ability of soil to adsorb NH₄⁺-N. The adsorption process of NH₄⁺-N by soil, which was dominated by monolayer adsorption, reached a significant level by matching the Langmuir equation (0.953 7<R²<0.995 5). After the application of biomass charcoal, the soil produced a known absorption hysteresis, which effectively reduced the desorption rate of NH₄⁺-N in tea garden soil, and the desorption rate of BC400 was the lowest. Tea residue biochar can enhance the adsorption of NH₄⁺-N in soil, reduce the desorption of NH₄⁺-N, improve the ability of soil to absorb nitrogen, and the treatment of BC400 with 2.80% addition showed the best effect.