A multi-dimensional approach to assess crop mapping and farmer strategies in drylands of Bamyan, Afghanistan

Context

Global warming's impacts on agriculture are well-documented, yet the multiple challenges farmers face, particularly regarding water resources, remain poorly understood. Despite substantial scientific research, regions like Afghanistan, where the level of undernourishment remains very high, still require in-depth investigations into the interactions between climate trends and agriculture. Similar to many arid agricultural regions globally, Afghanistan's agricultural systems have already suffered from depleted groundwater levels due to overuse and increasing drought frequencies due to shifting climate patterns. Therefore, interdisciplinary research on climate trends and adaptive strategies using available datasets is urgently needed in Afghanistan, where food security is one of the most critical challenges to address in the short term.

Objectives

This study aims to explain the current challenges faced by Afghan farmers related to their agricultural strategies - specifically, their crop choices and the reasons behind them - and the impacts of climate change on water resources using a holistic approach. After characterizing the crop choices, the agricultural practices and their related challenges using interviews and remote sensing, we aim to use CORDEX models, specifically downscaled for Northern Afghanistan, to analyze future predictions of key climate variables for agriculture. Our goal is to highlight future challenges and formulate recommendations to improve the adaptation of agricultural systems to climate change.

Methods

We applied crop mapping using Sentinel-2 imagery to quantify farmers' crop choices. Classification was performed using Google Earth Engine, following the Rapid Classification of Croplands instructions and ground-collected crop type data during the growing season in 2023. Along with remote sensing quantification, we conducted in-depth interviews with farmers to understand the economic and climate pressures they face in their agricultural systems. While the crop map shows the area for each crop type, it does not reveal the significant socio-economic reasons behind crop selection. To extract century-long trends of key climate variables for agriculture, we used projections from the World Climate Research Programme's Coordinated Regional Downscaling Experiment (CORDEX-CORE), adjusted to the local context of Afghanistan. Representative Concentration Pathways 8.5 and 2.6 were selected to illustrate the most optimistic and pessimistic greenhouse gas emission scenarios for the coming century.

Results and conclusions

Farmers predominantly cultivate potatoes (52 %), followed by wheat (37 %) and alfalfa (11 %), based on a crop map with an overall accuracy of 83 %. Family subsistence and profitability are the main reasons for their crop choices, and historical climate trends and droughts did not significantly influence the agricultural strategies of farmers, according to their interviews. The cultivation of profitable crops like potatoes has led to a significant drawdown of the groundwater level by 13 m over three decades due to the more intense use of water resources. Consequently, the monoculture of potatoes is unsustainable for local water resources. Climate predictions do not indicate significant changes in extreme precipitation under either RCP 2.6 or RCP 8.5 scenarios, but there is a noticeable trend of increasing heat days in the region over the next century. The number of days above 25 °C and 30 °C will rise, extending the growing season and raising temperatures. Concurrently, soil moisture is expected to decrease during this period, with possible consequences on the yields and productivity.

Significance

In this study was conducted a holistic analysis of the impacts of climate change on agricultural practices and water resources in Afghanistan. By integrating satellite imagery, farmer interviews, and climate projections, the findings provide crucial insights into sustainable farming strategies and highlights the urgent need for adaptive measures to ensure food security in the face of rising temperatures and water scarcity.