Characterizing Cropland Patterns Across North‐East Africa Using Time Series Vegetation Indices

Abstract

AbstractThe global community faces challenges of agroecosystem sustainability in the face of changing climate and intensified agriculture, particularly in Africa. In this study, annual and seasonal cropland Normalized Vegetation Difference Index (NDVI) trends and phonological variations, and associated key drivers in North‐East Africa were generated using Moderate Resolution Imaging Spectral‐radiometer NDVI of 8‐day satellite images and climate data between 2001 and 2020, which were further analyzed by a modified dynamic threshold method. The results showed that the annual cropland NDVI increased at an average rate of 0.0106 per year. The seasonal cropland NDVI was positive for the most significant changes observed in the boreal autumn season across the region. The start of the season and end of the season cropland NDVI in the boreal autumn season increased at an average rate of 0.015 (13.4% significant, p < 0.05), and 0.0151 × (12.8% significant, p < 0.05), respectively. The findings indicated that the boreal autumn season was getting longer, whereas the boreal summer season was becoming shorter during the last two decades. The most rapid cropland NDVI changes and maximum farmland NDVI variability were observed in the sub‐tropic warm arid and tropic warm semiarid agro‐ecological zones. The land surface temperature was found to be the main driving factor for the cropland NDVI and associated agroecosystem changes. This study provides essential information on the cropland productivity and shifting of greening patterns, which will support climate change mitigation measures at national and regional scales, contributing to sustainable agriculture.