Field data on aboveground net primary productivity, photosynthetically active radiation absorbed and the derived calculation of radiation use efficiency, from trials with Medicago sativa L and Lolium arundinacea (2020-2021).

Dataset description This dataset includes records of aboveground net primary productivity (ANPP), absorbed photosynthetically active radiation (APAR), and the derived radiation use efficiency (RUE). It also contains associated climatic variables for each evaluation period, specifically mean air temperature and cumulative precipitation. The data correspond to the 2020–2021 growing seasons and were obtained from successive harvests in field experiments conducted with Medicago sativa L. and Lolium arundinaceum in Colonia, Uruguay. Method for calculating APAR and RUE RUE values were derived from the Monteith equation as follows: RUE (g DM MJ⁻¹) = ANPP (g DM m⁻² t⁻¹) / ∑ (PARi (MJ m⁻² t⁻¹) × fPARg) Where:RUE = radiation use efficiencyANPP = aboveground net primary productivityPARi = incoming photosynthetically active radiationfPARg = fraction of photosynthetically active radiation intercepted by green vegetation The product of PARi and fPARg corresponds to the photosynthetically active radiation absorbed by the vegetation (APAR). Incoming photosynthetically active radiation (PARi) was estimated as 48% of incoming global radiation on a daily basis and then integrated over time. The equation used to estimate fPARg from NDVI was that proposed by Pellegrini et al. (2019). To estimate APAR during each growth cycle, the mean fPARg value (calculated from two consecutive NDVI measurements) was multiplied by the incoming photosynthetically active radiation for the same period (PARi, between NDVI measurements). The sum of these partial values over the entire growth period up to harvest corresponds to the total APAR. These calculations were performed for each harvest.