生物炭对干旱区绿洲农田土壤呼吸的影响

Effect of Biochar Addition on Soil Respiration of Oasis Farmland in Arid Areas

为探究不同粒径秸秆生物炭添加对绿洲农田土壤CO_2排放及Q10的影响,以新疆典型绿洲农田土壤灰漠土为供试材料,采用室内土柱培养的方法,研究添加>5、1～5、0.25～1和<0.25mm共4种粒径棉花秸秆生物炭和葡萄藤生物炭对农田土壤CO_2释放的影响。结果表明:(1)试验周期内(0～85d),添加生物炭处理土壤呼吸速率呈先增加后降低的趋势,前10d土壤呼吸增速较高;添加生物炭的土壤呼吸速率(1.27μmol·m^(-2)·s^(-1))高于不添加生物炭的对照处理(1.01μmol·m^(-2)·s^(-1)),棉花秸秆生物炭处理土壤呼吸速率(1.43μmol·m^(-2)·s^(-1))高于添加葡萄藤生物炭处理(1.08μmol·m^(-2)·s^(-1))。培养期内土壤CO_2累积过程符合一级反应动力学方程,生物炭添加改变了土壤CO_2潜在排放量、周转速率和半周转期。(2)添加棉花秸秆和葡萄藤两种生物炭处理与土壤CO_2累积排放量(y)分别符合y=7.51x+88.53和y=2.68x+75.85的线性关系(x为生物炭粒径)。(3)添加生物炭处理土壤呼吸速率与空气温度和土壤温度显著相关,棉花秸秆生物炭处理土壤呼吸速率与温度的相关性高于葡萄藤生物炭处理,土壤温度敏感系数随粒径的减小而增加。综合土壤呼吸速率和温度敏感系数考虑,建议绿洲农田施用1～5mm中等粒径生物炭。

In this paper,authors investigated the influence of biochar addition with four different particle sizes of cotton stalks biochar and vine biochar(>5,1-5,0.25-1 and<0.25mm)on the changes of soil CO2 emission using the soil column incubation method in a grey desert soil.The results showed that:(1)addition with biochar soil respiration rate increased first and then decreased during the incubation period(0-85d),and the increase of soil respiration in the former 10d was higher than that in the late stage.The soil respiration rate(1.27μmol·m-2·s-1)under the biochar addition was higher than that of the not biochar addition control treatments(1.01μmol·m-2·s-1),and the soil respiration rate under cotton stalk biochar(1.43μmol·m-2·s-1)was higher than that of the grapevine biochar addition treatments(1.08μmol·m-2·s-1).The accumulation of soil CO2 emission accorded with the first-order reaction kinetics equation during the incubation period.Biochar addition changed the potential emissions,the turnover rate and half-life time of soil CO2.(2)The equations of linear regression between the two biochar treatments and the cumulative emission of CO2 were y=7.51x+88.53 and y=2.68x+75.85(x was biochar particle diameter)for cotton stalks biochar and vine biochar,respectively.(3)Soil respiration rates under biochar addition were significantly correlated with air temperature and soil temperature.The correlation between soil respiration rate and temperature under cotton stalks biochar was higher than that of the grape vine biochar.The temperature sensitivity coefficient of CO2 emissions increased with the decrease in grain size.Considering the soil respiration rate and temperature sensitivity coefficient,we suggested that medium size biochar(1-5mm)should be applied in oasis farmland.