不同生物炭对赣南稀土尾矿地土壤有机碳矿化特性的影响

Effect of Different Biochar on Mineralization Characteristics of Soil Organic Carbon in Rare Earth Tailing Areas in Southern Jiangxi

为探讨不同生物炭对尾矿地土壤有机碳矿化特性的影响,以赣南稀土尾矿地为研究对象,设置了玉米秸秆、玉米芯、水稻秸秆、稻壳、芦苇秸秆、椰壳、杏壳、核桃壳、竹子及木屑生物炭10种处理,对土壤有机碳矿化及生物炭特征参数进行了研究。结果表明:(1)低有机质(4.07 g/kg)土壤条件下,生物炭的施用促进了土壤有机碳矿化,在培养的第15天后土壤有机碳的矿化速率基本稳定,其中木屑生物炭的土壤有机碳平均矿化速率最强,为CK的3倍,以玉米芯生物炭的土壤有机碳平均矿化速率最弱,较CK无显著差异。(2)二项式拟合曲线结果表明,生物炭pH值、C含量及N含量与土壤有机碳累计矿化量的拟合值R^(2)分别为0.7417、0.4524和0.6148。(3)通过对木屑和玉米芯生物炭的红外光谱及比表面积、孔径分析可知,玉米芯生物炭较木屑生物炭具有更加丰富的有机官能团和较大的BET比表面积、孔径和总孔体积。综上所述,外源生物炭的添加促进了赣南稀土尾矿地土壤有机碳的矿化,其中以玉米芯生物炭的土壤有机碳平均矿化速率最弱,且生物炭适宜的特征参数在减弱土壤有机碳矿化方面具有良好的潜力。

In order to explore the effects of different biochar on soil organic carbon mineralization characteristics of tailing land,ten biochar treatments of corn stover,corn kernel,rice straw,rice husk,reed straw,coconut husk,apricot husk,walnut husk,bamboo and woodchip biochar were set up in rare earth tailings land of southern Jiangxi to study the soil organic carbon mineralization and the characteristic parameters of biochar.The results showed that(1)the application of biochar promoted soil organic carbon mineralization under low organic matter(4.07 g/kg)soil conditions,and the rate of soil organic carbon mineralization was basically stable after the 15th day of incubation.The average rate of soil organic carbon mineralization of woodchip biochar was the strongest,which was three times higher than that of CK.The average rate of soil organic carbon mineralization of corncobs biochar was the weakest,which was not significantly different from that of CK.(2)The results of the binomial fitting curves showed that the R^(2)of the fit between biochar pH,Carbon content,nitrogen content and the cumulative mineralization of soil organic carbon were 0.7417,0.4524 and 0.6148,respectively.(3)Through the analyses of infrared spectra,the specific surface areas and pore diameters of the wood chips and corncob biochar,the corncob biochar had richer organic functional groups and larger BET specific surface area,pore diameter and total pore volume.The study showed that the addition of exogenous biochar improved the mineralization of soil organic carbon in the rare earth tailings site in southern Jiangxi,and the mineralization of soil organic carbon was the weakest in the case of corn cob biochar.The suitable characteristic parameters of biochar had a better potential in attenuating the mineralization of soil organic carbon.