Publications

Mpakairi, KS; Dube, T; Sibanda, M; Mutanga, O; Nin, E (2024). Remote sensing crop water productivity and water use for sustainable agriculture during extreme weather events in South Africa. INTERNATIONAL JOURNAL OF APPLIED EARTH OBSERVATION AND GEOINFORMATION, 129, 103833.

Abstract
The impact of climate variability and extreme weather events on agricultural productivity in arid environments has become a focal point in contemporary research. Monitoring crop water productivity (CWP) is critical and urgently required especially in the arid regions where agriculture consumes an above-average portion of the available fresh water resources. In this context, this study aimed to demonstrate the utility of remotely sensed data in assessing CWP and water use dynamics across diverse crop types in South Africa during the El Nino (2018/19) and non-El Nino (2021/22) events. In addressing the objective, the study also assessed the intra- and inter-annual variations in crop water productivity for diverse crop types including, grains, grapes, citrus fruits, teas, planted pastures, and oil seeds. The study used potential evapotranspiration and biomass derived from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite to estimate CWP from 2017 to 2021. This period included El Nino (2018/19) and non-El Nino (2021/22) years. The results showed that potential evapotranspiration (PET) derived from MODIS was related to the PET estimated from weather stations (R-2 > 0.6; RMSE < 21.90; p-value < 0.001). In terms of water use, planted pastures had the highest water use 114 mm/ month), while teas and citrus fruits had the lowest water use (6 mm/month). Citrus fruits, grapes and teas consistently had the lowest annual mean crop water productivity (<0.02 kg/m(3)/annually), while oil seeds had the highest annual mean crop water productivity (>0.1 kg/m3/annually). Lastly, there were no significant differences (p-value > 0.05) between the CWP for all the crops observed between El Nino (2018/19) and non-El Nino (2021/22) periods, suggesting the effectiveness of adaptation measures and interventions during this period. These results provide a simple, spatially explicit framework, relevant to understanding crop-water use, laying the groundwork for informed decision-making and sustainable agricultural practices. Integrating these findings into policy frameworks and agricultural strategies is paramount for ensuring food security and resilience in a changing climate.

DOI:
10.1016/j.jag.2024.103833

ISSN:
1872-826X