Effects of nitrogen addition and elevated carbon dioxide on microclimate vapour pressure deficit in a semi‐arid grassland

Our study is based on an open top chamber that includes two treatment factors: nitrogen addition and elevated carbon dioxide concentration, including control (C), nitrogen addition (N), elevated carbon dioxide (CO2), and nitrogen addition plus elevated (CO2+N). Repeat each treatment 6 times. Install sensors at the center of each plot to collect air temperature (AT), relative humidity (RH), and vapor pressure deficit (VPD). Using Li-6800 to measure stomatal conductance (Cond) and ecosystem evapotranspiration (ET), and using ADC camera to determine the normalized vegetation difference index of each plot. The data includes the annual average and multi-year mean from 2021 to 2023