Based on micrometeorology, the study of energy dynamics and the exchange of gases between the biosphere and the atmosphere is a key tool to know the eco-physiology of coffee production systems, helping to understand the influence of climate variables on crops growth and production. In this research the energy, carbon and water dynamics were determined in four types of coffee agroecosystems typical of the Andean equatorial slope: Agroforestry or under shade with Guandul (Cajanus cajan L.), with maize, with bush bean and under full sun exposure. Using the Eddy Covariance method (EC), the energy balance was established by measuring its components: latent heat flux, sensible heat flux and soil heat flux, and their distribution, according to different climatic periods. This allowed to make inferences about the agroecosystems response to the radiative supply, finding differences in water, light and carbon use efficiency, depending on their composition and structure. The net ecosystem exchange of CO2 (NEE) between the atmosphere and each agroecosystem, and its partition into gross primary productivity (GPP) and ecosystem respiration (Reco) was evaluated; this information, together with energy and water balance, allowed the construction of ecophysiological indicators such as water use efficiency as a function of GPP, and light use efficiency, through photosynthetically active radiation . We determined in this study, mathematical functions and parameters that explain, at a potential level, the storage of carbon by photosynthesis as a response to solar radiation. The final contribution of this work was to obtain a general explanatory model of GPP, from measurements which, for the first time in Colombia, integrate the soil-plant-atmosphere components at the same time and space scale, in a coffee agroecosystem under full sun exposure. This was done through the relationships found between the rate of increase of gross primary productivity and climatic variables.

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