茶尺蠖侵染对贵州有机茶园土壤有机碳碳排放的影响

Soil carbon pool is the largest terrestrial ecosystem carbon stocks. Due to agricultural activities, it leads to increase atmospheric carbon dioxide. Soil organic carbon can easily be distributed by some factors. In especial, soil organic carbon of cropland is very fragile coming into atmosphere by disturbance and feedback to climate change. Projection of future climate change will promote diseases and pests outbreak. The development of organic agriculture in China rapidly is the important development trend of future agriculture. Based on previous research, pest and disease disturbance reduced soil organic carbon by declining litter and increasing soil respiration. But, the soil organic carbon decomposition process remains great uncertainty because of the quality of the input litter and microbial under pests and diseases. In order to simulation of pest and disease infection, Ectropis oblique hypulina Wehrli would be inoculated in tea plantation. Collecting litter for testing the hypothesis that litter input promotes soil organic carbon decomposition. Analysis of soil microbial community structure and composition of dissolved organic carbon, verify root exudates changed the composition of the microbial community affecting soil organic carbon decomposition hypothesis. Similarly, the determination of the different functional components and the carbon content of soil organic carbon in the root exudates of carbon components, verify pest infestation induced changes in soil carbon decomposition and transformation of labile carbon and inert hypothesis. Likewise, biomarkers of soil organic carbon can trace conversion process. Thus, we integrated spectrometry and biomarkers methods discover soil carbon transform and test labile and resistant carbon decomposition hypothesis..The results will offer key parameters for understanding effects for soil carbon sink and emission in cropland. Furthermore, it provides necessary and basic data for policy-making and management of cropland pest and disease affecting litter and soil organic carbon decomposition.

土壤碳库是陆地生态系统最大的碳库，农田土壤碳库很脆弱容易受到干扰并反馈于气候变化。气候变暖，促进病虫害发生。有机农业是农业的重要发展趋势。基于项目前期研究，病虫害侵染减少了土壤有机碳的输入促进了碳的排放，导致土壤有机碳降低。但是，关于病虫害发生后，对土壤有机碳的排放仍然存在很大的不确定性。本项目以贵州有机茶园及重要的虫害茶尺蠖为对象，研究有茶树遭受尺蠖侵染后对土壤有机碳过程及碳排放的影响，收集茶尺蠖侵染后凋落物的输入，验证凋落物输入促进土壤有机碳分解假说；分析土壤微生物群落结构组成和可溶性有机碳，验证土壤可溶性碳输入改变了微生物群落组成，进而影响土壤有机碳分解假说。同时，测定土壤有机碳中不同功能组分碳含量和可溶性碳组分，验证病虫害侵染诱导改变了土壤有机碳输入，加速了惰性碳分解降低了土壤有机碳假说，揭示病虫害侵染对土壤有机碳的分解转化过程，为有机农田碳减排及相关的决策部门提供必要的科学依据。

在过去的100年间，全球气候呈现出变暖趋势，气温平均升高了0.74℃。冬季气温的增加有利于害虫的虫卵/病原孢子越冬，而生长季温度增加又加速了病虫害的发育速度、缩短了病虫害的世代时期。气候变化是病虫害发生的重要驱动力，气温升高与极端事件促进了病虫害的爆发并向新的区域蔓延传播。病虫害侵染植物后生产力降低，关于病虫害对生态系统功能方面的研究甚少。土壤碳库很容易受到外界环境的扰动从土壤圈进入大气圈，反馈于气候变化。据研究由于农业活动和土地利用方式转变，对大气二氧化碳的贡献约33%。因此，探讨病虫害侵染对土壤有机碳的转化机制。.研究结果表明：（1）茶尺蠖侵染后土壤活性有机碳增加；（2）稳定性有机碳增加，随着时间的推移，土壤活性有机碳和微生物碳含量呈现降低趋势；（3）茶尺蠖侵染后改变了土壤活微生物群落结构发生变化，土壤中的细菌、真菌、放线菌和原生动物数量呈现增加趋势，土壤微生物中真菌的数量稍微高于细菌增加。土壤真菌呈现稍微增加趋势；（4）茶尺蠖侵染后土壤有机碳中酚基、羟基或羧基结构的增加；脂肪族土壤有机碳增加。土壤中的芳香性有机碳比例上升, 芳香性趋于升高和增强。由于这些基团相对比较稳定，在中后期出现稍微的变化，间接证明土壤有机碳相对比较稳定。茶尺蠖侵染后随着时间的推移，与对照相比土壤有机碳降低0.4%-0.9%。.总之，用土壤有机碳标志物研究表明茶园土壤有机碳没有明显变化。茶尺蠖侵染改变了土壤有机碳的组成变化，影响了土壤微生物群落组成结构，激发了土壤有机碳的矿化。本研究表明茶尺蠖干扰后，土壤稳定性有机碳无显著变化，土壤活性有机碳变化较大，中稳定性有机碳和稳定性土壤有机碳无明显变化。意味着土壤有机碳的稳定是大量中稳定性好稳定性有机碳的稳定。