Parton William J, Morgan Jack A, Wang Guiming, Del Grosso Stephen
Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523-1499, USA.
USDA Agricultural Research Service, Rangeland Resources Research Unit, 1701 Centre Ave., Fort Collins, CO 80526, USA.
New Phytol. 2007;174(4):823-834. doi: 10.1111/j.1469-8137.2007.02052.x.
The Prairie Heating and CO2 Enrichment (PHACE) experiment has been initiated at a site in southern Wyoming (USA) to simulate the impact of warming and elevated atmospheric CO2 on ecosystem dynamics for semiarid grassland ecosystems. The DAYCENT ecosystem model was parametrized to simulate the impact of elevated CO2 at the open-top chamber (OTC) experiment in north-eastern Colorado (1996-2001), and was also used to simulate the projected ecosystem impact of the PHACE experiments during the next 10 yr. Model results suggest that soil water content, plant production, soil respiration, and nutrient mineralization will increase for the high-CO2 treatment. Soil water content will decrease for all years, while nitrogen mineralization, soil respiration, and plant production will both decrease and increase under warming depending on yearly differences in water stress. Net primary production (NPP) will be greatest under combined warming and elevated CO2 during wet years. Model results are consistent with empirical field data suggesting that water and nitrogen will be critical drivers of the semiarid grassland response to global change.
草原升温与二氧化碳富集（PHACE）实验已在美国怀俄明州南部的一个地点启动，以模拟变暖和大气二氧化碳浓度升高对半干旱草原生态系统的生态系统动态的影响。DAYCENT生态系统模型经过参数化处理，用于模拟科罗拉多州东北部开放式顶棚箱（OTC）实验中二氧化碳浓度升高的影响（1996 - 2001年），还用于模拟未来10年PHACE实验对生态系统的预计影响。模型结果表明，高二氧化碳处理下土壤含水量、植物产量、土壤呼吸和养分矿化将增加。所有年份的土壤含水量都会下降，而氮矿化、土壤呼吸和植物产量在变暖情况下会根据水分胁迫的年度差异而减少或增加。在湿润年份，变暖与二氧化碳浓度升高共同作用下净初级生产力（NPP）将最大。模型结果与实地经验数据一致，表明水和氮将是半干旱草原对全球变化响应的关键驱动因素。
