凋落茶叶对华中地区酸化茶园土壤N_2O与CO_2排放的影响

Effects of tea litter applications on N_2O and CO_2 fluxes from acidification of tea garden soil in Central China

采用室内培养试验方法,研究了凋落茶叶添加(0、5、10 g·kg-1和20 g·kg^(-1))对酸化茶园土壤N_2O和CO_2排放特征的影响。结果表明:4种添加水平下,N_2O和CO_2排放通量分别为0.24~3.92μg·kg^(-1)·h^(-1)和0.33~1.84 mg·kg^(-1)·h^(-1);凋落茶叶的添加显著促进了酸化茶园土壤N_2O和CO_2排放(P<0.05),且两种气体的排放通量随着凋落茶叶添加量的增加而增加;凋落茶叶显著提高了酸化土壤pH值(P<0.05),且添加量越多,pH值变幅越大,其一定程度上改善了茶园土壤酸化现象。茶园土壤铵态氮与N_2O排放通量呈极显著相关,而硝态氮与N_2O排放通量未呈显著相关性。土壤可溶性有机碳含量与N_2O和CO_2排放通量均呈极显著相关关系。茶园土壤N_2O排放通量和CO_2排放通量呈极显著正相关。研究结果有助于阐明凋落茶叶对茶园土壤温室气体排放的作用规律,且对了解茶园生态系统碳氮循环有一定的理论意义。

Tea litter may impact soil microbes and soil properties, thus greenhouse gas emissions from soil. In this paper, a laboratory study was conducted to investigate N2O and CO2 fluxes from acidification of tea garden soil receiving different amounts of tea litter：0, 5, 10 g·kg-1 and 20 g·kg-1 soil. Results showed that N2O and CO2 fluxes from four treatments ranged from 0.24μg·kg-1·h-1 to 3.92μg·kg-1·h-1 and 0.33 mg·kg-1·h-1 to 1.84 mg·kg-1·h-1, respectively. Tea litter applications significantly increased N2O and CO2 fluxes（P〈0.05）in a dose-effect manner. Soil pH values from three tea litter treatments were significantly higher（P〈0.05）than that from the control treatment, and the pH values increased with increasing amounts of tea litters added. The N2O emissions from tea garden soil had significantly positive correlation with soil NH＋4-N content, but did not show relationship with soil NO-3-N. Soil DOC content was significantly positive correlated with N2O and CO2 fluxes. There was highly significant and positive correlation between N2O and CO2 fluxes in tea garden soil. These results would advance our understanding of greenhouse gas fluxes and carbon and nitrogen cycling in tea garden soil system.