Remote sensing-based assessment of dry-season forage quality for improved rangel and management in sahelian ecosystems

Lo Adama, Diouf Abdoul Aziz, Leroux Louise, Tagesson Torbern, Fensholt Rasmus, Mottet Anne, Bonnal Laurent, Diédhiou Ibrahima. 2024. Remote sensing-based assessment of dry-season forage quality for improved rangel and management in sahelian ecosystems. Rangeland Ecology and Management, 96 : 94-104.

https://doi.org/10.1016/j.rama.2024.05.009

Article de revue ; Article de recherche ; Article de revue à facteur d'impact

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Url - autres données associées : https://github.com/adamalo/CaSSECS_FATIMA_files

Résumé : Residents of the Sahel depend on livestock, but harsh environmental conditions during the dry season limit rangeland forage, which is the main source of livestock feed. Al-though operational tools exist for assessing and monitoring forage quantity during the dry season, assessments of forage quality are lacking. We addressed this gap by developing satellite-based monitoring of forage quality across Sahelian rangelands during the dry season. Acid detergent fiber (ADF), neutral detergent fiber (NDF), and crude protein (CP) content (%) were measured in forage samples collected from 11 sites across the Senegalese rangelands in 2021. Multilinear (MML) regression and support vector machine (SVM) models were calibrated with spectral indices to estimate these parameters of forage quality. The vegetation variables assessed were herbaceous mass (HQ), woody foliage mass (LQ), and total fo-rage mass (HLQ). The MML regression provided the most accurate estimates for CP (HQ: R2 = 0.81, LQ: R2 = 0.72, and HLQ: R2 = 0.70), ADF (HQ: R2 = 0.70, LQ: R2 = 0.77, and HLQ: R2 = 0.61), and NDF (HQ: R2 = 0.47, LQ: R2 = 0.83, and HLQ: R2 = 0.60). Temporal analysis revealed a slight decrease in CP and an increase in fiber during the dry season. Spatial analysis indicated that CP was higher in the steppe zone than in the savanna zone, and a decrease correlated with the rainfall gradient. The HQ alone was insufficient to meet livestock needs during the dry season, highlighting the importance of woody plants as an additional forage source. These findings will improve feed balance calculations in Sahelian countries, enable more sustainable use of rangelands, and contribute to the resilience of Sahelian communities to climate change.

Mots-clés Agrovoc : télédétection, fibres insolubles dans les détergents acides, rangeland improvement [EN], qualité, spectroscopie infrarouge, facteur du milieu, saison sèche, parcours, fibre détergente neutre, suivi des terres de parcours

Mots-clés géographiques Agrovoc : Sahel, Sénégal

Mots-clés libres : Crude protein, Dry vegetation, Fibers, Nutritional value, Sentinel-2, Silvopastoral

Agences de financement européennes : European Commission

Agences de financement hors UE : Swedish National Space Agency, Svenska Forskningsrådet Formas

Projets sur financement : (EU) Carbon Sequestration and Greenhouse Gas Emissions in (Agro) Sylvopastoral Ecosystems in the Sahelian CILSS States (CaSSECS), (EU) Development Smart Innovation through Research in Agriculture, (EU) FArming Tools for external nutrient Inputs and water MAnagement

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