Author：Ming-Hwi Yao¹, Chun-Jen Chen²

¹ Senior Agricultural Engineer, Taiwan Agricultural Research Institute, COA
² Assistant Agricultural Engineer, Taiwan Agricultural Research Institute, COA

Abstract：

    The eddy correlation system was setup above crop canopy to record the flux data during crop growth for evaluate the model and monitor the agricultural environment. The uptake of carbon dioxide in rice paddies may play an important role in balancing the budget of greenhouse gases, As a result, the average net daily CO₂ uptake in first crop was 22 g m^-2 day^-1, while it was 17.92 g m^-2 day^-1 in second crop. To evaluate the best temperature and light intensity conditions of Phalaenopsis facility by the measurement of daily carbon balance with CO₂ flux using eddy covariance technique for the purpose of improving orchid management in greenhouse cultivation, the results indicated the maximum carbon balance can be reached at the day/night temperature of 25/25℃ on leaf basis, and in range of 24-27℃ on the base of facility as a whole. Determining of the water requirement of rice is important for paddy field irrigation plan, this study were to measure evapotranspiration with eddy correlation system, and to validate four empirical equations of potential evaportranspiration by comparing the model’s estimated values to calculated values of latent heat flux from paddy field, the results showed that Penman-Monteith method and its derived simplified equation (Priestley-Taylor method) were better fitted to the actual measurement values. In addition to, monitor the physiological responses of litchi (Litchi chinensis) in large field areas using the technique of flux measurement. The latent heat flux was highly correlated to the vapor pressure deficit which was calculated by measuring temperature and relative humidity (r = 0.70). Therefore, this study suggests that the vapor pressure deficit is a good index for the water management in litchi orchards.

Keywords: Flux、Crop model、Climate change、Greenhouse gas、Evapotranspiration.