Remote sensing

Estimation of forage biomass on plots using satellite imagery.

The "Normalized Difference Vegetation Index" (NDVI), or Normalized Vegetation Index Is calculated from the "red" and "near infrared" (PIR) spectral bands of a so-called multispectral satellite image. The PIR reacts to the chlorophyll in plants. It therefore allows us to estimate the forage biomass present on plots. It is a non-destructive method that allows the collection of data over large surfacea areas and from a distance. To do this, a field survey phase is required beforehand in order to link the quantity of biomass in the field to the calculated NDVI. This work was carried out during the first phase of the ARChE_Net project. A web interface will be set up to allow quick access to the information.

Initially, the objective of the studies conducted through the NDVI is to validate one or more soil-climate dependent models for each country in the Indian Ocean region. The satellite images measure the evolution of plant activity during the different seasons and the data acquired by the satellites, in the visible and near infrared regions, is used to calculate NDVI indices; these indices are highly correlated with the density of the vegetation cover and the capacity of the plants to absorb sunlight and to convert it into biomass.

Thus, the biomass monitoring tool interrelates the soil-climate dependent grass growth models and the geo-referenced information (NDVI indices, meteorological data, ground measurements) to map (Geographic Information System) the availability and nutritional value of forage resources in an area. The tool can provide real-time information that enables livestock producers to manage their livestock numbers better and/or the mobility of their herds in relation to the expected availability of fodder resources.


Follow-up of the progress of the work: Summary of Cyprien ALEXANDRE’s thesis

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