不同秸秆炭在黄壤中降解特征的比较研究

Comparative Study on Degradation Characteristicsof Different Straw Biochar in Yellow Soil

为了估算油菜、玉米和水稻秸秆炭在黄壤中的降解率、表观残留碳量和降解半衰期等降解参数,明确不同秸秆炭在黄壤中的降解特征,采用添加秸秆炭至黄壤中的方法进行室内培养试验,通过耗氧培养过程中总碳的变化来模拟研究秸秆炭在土壤环境中的降解特征.结果表明,黄壤的全碳含量和表观残留碳量与投入至黄壤的纯碳量有关,随其投入纯碳量的增加而增加,4%添加量的3种秸秆炭均可使黄壤的全碳含量由初始的第4等级提高至第1等级.随着培养时间的持续秸秆炭逐渐降解,其降解率由大到小依次为:玉米秸秆炭、水稻秸秆炭、油菜秸秆炭.最终通过公式T_(1/2)(月)=0.693/K计算出油菜、玉米和水稻秸秆炭的降解半衰期分别为4.9~8.2,3.9~6.0,3.0~5.3年.秸秆炭对黄壤的增碳效果取决于投入秸秆炭的纯碳量,而其稳定性与秸秆炭的种类有关,在同一添加量水平下,玉米秸秆炭对黄壤的增碳效果最佳,而油菜秸秆炭的稳定性最好.

The degradation parameters such as the degradation rate,apparent residual carbon content and degradation half-life of rape,corn and rice straw biochar in yellow soil were estimated,and the degradation characteristics of different straw biochar in yellow soil were clarified.Indoor culture experiments were carried out by adding straw biochar to yellow soil,and the degradation characteristics of straw biochar in soil environment were studied by simulating the change of total carbon in the system during aerobic cultivation.The total carbon content and apparent residual carbon content of yellow soil were related to the pure carbon input into the yellow soil,and increased with the increase of the pure carbon input.The addition of 4%of the three kinds of straw biochar could increase the total carbon content of the yellow soil from the initial fourth grade to the first grade.With the passage of culture time,the straw biochar was gradually degraded,and its degradation rate from large to small was as follows:corn straw biochar,rice straw biochar,rape straw biochar.Finally,the degradation half-lives of corn,rice and rape straw biochar were estimated to be 4.9-8.2,3.9-6.0 and 3.0-5.3 years by the degradation formula T_(1/2)(month)=0.693/K,respectively.The carbon-increasing effect of yellow soil is limited by the amount of pure carbon added,and its stability is related to the type of straw biochar.Our results showed that corn straw biochar has the largest carbon-increasing effect,and rape straw biochar was the most stable in yellow soil at the same addition amount level.