Abstract

GALLEGO, Federico et al. Estimating Aboveground Net Primary Production and Carrying Capacity: a Case Study in Sierras del Este, Uruguay. Agrociencia Uruguay [online]. 2017, vol.21, n.1, pp.120-130. ISSN 1510-0839.

In livestock production systems under grazing it is essential to know the Carrying Capacity (CC). Aboveground Net Primary Productivity (ANPP) is the most important variable to estimate the CC as it represents the main source of energy for herbivores. The ANPP can be estimated from successive biomass harvests or from spectral information. The aim of this study was generate information about the ANPP, for two grassland units (dense and open), based on satellite data. For this purpose, the Efficiency in the Use of the Radiation (EUR) was determined for two grasslands units, by combining satellite and field data. In turn, we estimated, based on a simplified method, the CC of a representative cattle farm in Sierras del Este region. EUR was 0,38 and 0,44 grMS/MJ (Dry Matter/Mega Joules) for dense and open grasslands, respectively. The EUR for each grassland unit did not show significant differences. For this reason the total EUR was of 0,36 grMS/MJ. The average ANPP for the 14 years of the dense and open grasslands was 2876 and 1711 kgMS/ha*year, respectively. The average CC for the analyzed farm was 0,44 UG/ha. CC varied among paddocks depending on the relative importance of each grassland unit. The ANPP information generated and the CC estimation procedure used in this study provides to technicians and producers a simple way to estimate the CC of their farm.

Keywords : remote sensing; radiation use efficiency; grasslands.

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