Near real-time Feed On Offer (FOO) from MODIS for early season grazing management of Mediterranean annual pastures

Abstract

Near real-time estimation of Feed On Offer (FOO) from Moderate Resolution Imaging Spectroradiometer (MODIS) data was developed to help farmers improve their grazing management during early growth of annual pastures to maximize grass utilization for wool production. Data were collected from 72 fields on 15 farms in southwestern Australia. From these data, an exponential relationship at the field scale between the Normalized Difference Vegetation Index (NDVI) estimated from MODIS and FOO data was derived for the vegetative growth phase for FOO between 0 and 2000 kg ha^–1 (R ² = 0.71–0.75). This relationship transformed the dimensionless index NDVI to a dimensioned (kg ha^–1) measure of FOO, from which farmers could apply extension advice received from the Western Australian (WA) Department of Agriculture and Food Production (DAFP). Above an FOO of 2000 kg ha^–1 or when the annual pasture species began to senesce, the relationship ceased to have predictive value. Near real-time estimates of FOO from MODIS proved useful to farmers despite an apparent standard error of ±300 kg ha^–1. How to reduce the errors in FOO predicted from MODIS NDVI is also discussed.