Português Calibração de um medidor de prato ascendente na estimativa da produtividade de pastagens biodiversas de sequeiro

Calibração de um medidor de prato ascendente

Abstract

This study evaluates a expedient electronic sensor, a rising plate meter (RPM), to estimate pasture dry matter (DM, in kg ha⁻¹). The sampling process was carried out throughout the 2023/2024 pasture growing season. A total of 192 composite pasture samples were collected in two phases (calibration and validation). The calibration phase (n = 144) consisted of measurements on three dates (December 2023, February and  May 2024). On each of these dates, measurements were carried out in 48 georeferenced sampling areas of a 4 ha experimental field. This pasture is representative of biodiverse permanent dryland pastures of Alentejo, a mixture of various botanical species, grazed by sheep. The validation phase (n = 48) was carried out between December 2023 and April 2024 in the same experimental field. The best estimation model for DM was obtained based on measurements carried out in February 2024 (R² = 0.82). The results of this exploratory study in Portugal open perspectives for other works that would allow the testing, calibration, and validation of these electronic sensors in a wider range of pasture production conditions, in order to improve their accuracy as decision-making support tools in pasture and grazing management.