生物黑炭输入对茶园土壤呼吸的影响

生物黑炭是化石燃料或生物质不完全燃烧产生的一种非纯净碳的混合物，施入土壤后能有效减少温室气体排放、改良土壤性状、促进植物生长，但生物黑炭施用对土壤碳排放的影响仍存在不确定性。茶园是我国南方地区主要土地利用类型之一，为明确生物黑炭输入对茶园土壤碳排放的影响，本文采用田间试验研究生物黑炭施用对茶园土壤呼吸的影响。试验设置生物黑炭施用量0 t·hm^-2（CK）、8 t·hm^-2、16 t·hm^-2、32 t·hm^-2和64 t·hm^-25个水平，采用LI-Cor8100开路式土壤碳通量测定系统对不同生物黑炭施用水平处理下茶园土壤呼吸速率进行长期定位观测。结果表明，茶园土壤呼吸速率的季节变化规律呈现单峰曲线特征，最高值出现在8月份，最低值出现在1月份；土壤呼吸速率与土壤10 cm温度呈极显著的指数相关关系，土壤10 cm温度能够解释各处理土壤呼吸月动态变化的67.79%-89.16%。生物黑炭输入提高了茶园土壤呼吸速率，各处理年平均土壤呼吸速率分别比CK提高10.75%、17.52%、35.78%和42.58%，并与CK差异达显著水平（p〈0.05）；生物黑炭输入降低了茶园土壤呼吸敏感性（Q10值），各处理土壤呼吸Q10值分别比CK降低1.96%、3.14%、4.01%和10.76%。土壤呼吸温度敏感性的降低验证了生物黑炭具有热稳定性和生物学稳定性，是可以在茶园土壤中长期固存的惰性有机碳。

Effect of biochar application on soil respiration in tea plantation

Biochar is a mixture of non pure carbon by incomplete combustion of fossil fuel or biomass. It could effectively reduce greenhousegas emissions, improve soil properties and plant growth after applied into soil, but the effects of biochar application on soil carbon emissions are still uncertain. Tea plantation is one of the main land-use types in the southern area of China. In order to investigate the effects of biochar application on soil respiration, a long-term field experiment with five biochar application treatments included 0（CK）, 8, 16, 32, 64t·hm-2 was carried out, by using LI-8100 automated soil CO2 flux system. The results showed that the monthly variation of the soil respiration in tea plantation expressed in a single-peaked curve, the peak appeared in August, the lowest value appeared in January. There was a significant positive correlation between the soil respiration rate and soil temperature at 10 cm depth in tea garden, and soil temperature at 10 cm depth could explained 67.79%-89.16% of the monthly variation of soil respiration. The application of biochar could increase the soil respiration rate, which were increased 10.75%, 17.52%, 35.78%, 42.58% contrasted to CK by the application of biochar rate at 8, 16, 32, 64 t·hm-2, respectively. Moreover, the application of biochar could decrease theQ10 value of soil respiration, theQ10 value decreased 1.96%, 3.14%, 4.01%, 10.76% by the application of biochar rate at 8, 16, 32, 64 t·hm-2, respectively. The thermal stability and biological stability of biochar were verified by the reduced of the sensitivity of soil respiration to temperature. It could be concluded that biochar is an inert organic carbon that could be long-term sequestrated in the soil of tea plantation.