臭氧升高对东北典型黑土区旱田土壤跳虫功能群和碳动态的影响

Elevated ozone would significantly reduce plant yields and amplify the "greenhouse effect" due to the alteration of carbon allocation pattern. In black soil region in Dehui, modified-open top chambers were used to simulate the circumstance of elevated ozone concentration, and the response of functional group of Collembola and carbon dynamics in maize-soybean rotation system were investigated under elevated concentrtion of ozone. Phospholipid fatty acids (PLFAs) and stable C13 isotope analysis were adopted to clarify the feeding relationships among functional group of soil Collembola, microbes and crops. In different growth periods of maize and soybean, dissovled organic carbon, mineralizable carbon and soil respiration were determined to indicate carbon input and output that were connected with functional group of soil Collembola. In upland agroecosystem in Northeast China, We want to uncover the relationships and alterations between functional group of soil Collembola and carbon input/output under current atmospheric condition and elevated ozone concentration. We would 1) predict carbon input/output under elevated ozone concentration in different crop growth periods, 2) interpret response mechanisms of ecological process and productivity under climate change conditions, and 3) provide fundermental data to ascertain the mechanisms of elevated ozone concentration on food production.

大气O3浓度升高可以使作物减产，加剧温室效应。这种影响很大程度上是由于碳分配格局变化所造成的。在东北德惠黑土区，利用改进的开顶式气室研究O3浓度升高对玉米-大豆轮作农田跳虫功能群和土壤碳动态的影响；以磷脂脂肪酸结合C13同位素的方法阐明跳虫对微生物和植物的取食关系；以不同作物生长期玉米和大豆根际土壤可溶性有机碳、可矿化碳和土壤呼吸表征土壤跳虫功能群（土壤跳虫-微生物-植物）相关的土壤碳输入和输出；解析当前大气状态下东北主要旱作农田中跳虫功能群与土壤碳输入和输出的关系；揭示未来O3浓度升高对这种关系产生的影响。通过上述研究可以预测大气O3浓度升高下，东北旱作农田生态系统不同作物生长期土壤碳收支的变化；同时，从碳形成物变化和土壤动物功能群结合的角度，解释气候变化对作物地下生态过程及相关生产力影响的机制，为调查未来大气O3浓度升高对东北地区粮食产量影响的总体机制提供必要的地下理论基础。

大气O3浓度升高可以通过影响地上、地下碳源物质分配使作物减产，加剧温室效应。本项目在东北黑土区，利用改进的开顶式气室研究O3浓度升高对玉米—大豆轮作农田跳虫功能群和土壤碳动态的影响；以磷脂脂肪酸结合13C同位素的方法阐明跳虫对微生物和植物的取食关系；以不同作物生长期玉米和大豆根际土壤可溶性有机碳变化表征碳源物质变化。研究发现跳虫的取食特性是以根系为主的食物，根系生物量在作物不同生长时期的变化对跳虫群落起决定性作用。臭氧升高通过降低根系生物量及相关的碳源物质地下分配，降低了根际的可溶性碳和土壤跳虫的密度，这可能会对未来地下生态系统碳循环及相关的作物产量都发生严重的影响。而臭氧升高并未改变作物凋落物性质，因而通过凋落物途径并未对跳虫产生显著影响。本研究解释气候变化对作物地下生态过程及相关生产力影响的机制，为调查未来大气O3浓度升高对东北地区粮食产量影响的总体机制提供必要的地下理论基础。