[PhD’s Corner] Enzo Castro : Exploiting multi-year high-resolution Sentinel image time series for a better understanding of fallow dynamics in West Africa

Enzo Castro is one of the #DigitAg co-funded PhDs


Exploiting multi-year high-resolution Sentinel image time series for a better understanding of fallow dynamics in West Africa

  • Starting date: 1st December 2020
  • University: AgroParisTech, Montpellier
  • PhD School: GAIA
  • Field(s): Sciences of Earth and water
  • Doctoral Thesis Advisor: Agnès Bégué, UMR Tetis, Cirad
  • Co-supervisors : Raffaele Gaetano, Tetis, Cirad/ Louise Leroux, Aida, Cirad
  • Funding: #DigitAg – Cirad
  • #DigitAg: Axis 5:Data Mining, Data Analysis and Knowledge Discovery, Axis 6: Multiscale modelling and simulation, Challenge 1: ICT and the agroecology challenge, Challenge 4: ICT and sustainable animal production, Challenge 6: ICT and agricultural territory management, Challenge 8: ICT and agricultural development in Southern countries (Africa)

Keywords: Tropical agricultural systems, fallows, land use, remote sensing, Sentinel, radar and optical imagery, multi-year time series

Abstract: Extensive farming systems, still widespread in the tropics, are generally based on fallow practices, because of their ability to regenerate soil fertility, particularly through the maintenance of biomass reservoirs. Their importance has also been emphasized in adaptation to climate change, as they contribute to carbon sequestration and the reduction of greenhouse gases. As a result, the estimation of fallow areas is an important piece of information in assessing the performance of an agricultural system, both in terms of short-term productivity and the quantification of the “land stock” available for the establishment of strategies in response to climatic and/or anthropogenic factors. If the documentation of this practice in different regions of the world is important, a regular and exhaustive inventory of fallow land in West Africa does not exist. Given the stakes involved in this practice, this thesis aims to define a methodological framework combining expert knowledge and satellite imagery for the implementation of a fallow monitoring system at large scale. Indeed, fallow mapping is poorly taken into account in real-world remote sensing based land cover products. At best, this problem is naively approached omitting any consideration of the specificities related to these practices (extents, durations, strategies, but also their role in landscapes). In order to overcome these limitations, and with a growing availability of satellite images adapted to the monitoring of West African complex agricultural landscapes (such as those from ESA’s Sentinel missions), we will promote an interdisciplinary approach to (i) study the relationship between fallow land use and remote sensing indicators and (ii) to convey this information in the design of methods for analyzing multi-year series of images for their identification and characterization.

Contact: nzcstr [AT] gmail.com – Tel: 07 54 19 65 75