Study on the Seasonal Dynamic of Net Ecosystem Exchange over a Poplar Plantation of Yueyang City in Hu’nan Province Characteristics of net ecosystem exchange and environmental factors of rice-wheat rotation system in the Yangtze River Delta of China Analysis of net ecosystem CO2 exchange (NEE) in the rice-wheat rotation agroecosystem of the Lake Taihu Basin, China Impacts of solar radiation on net ecosystem carbon exchange in a mixed plantation in the Xiaolangdi Area Net ecosystem carbon exchange and its main driving factors in meadow grassland ecosystems in the Horqin Sand Lands EFFECTS OF SOLAR RADIATION ON NET ECOSYSTEM EXCHANGE OF BROADLEAVED-KOREAN PINE MIXED FOREST IN CHANGBAI MOUNTAIN, CHINA