Recent changes in cropland area and productivity indicate unsustainable cropland expansion in Malawi
Recent changes in cropland area and productivity indicate unsustainable cropland expansion in Malawi
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DOI：
10.1088/1748-9326/ac162a
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发表时间：
2021
影响因子：
6.7
通讯作者：
Chengxiu Li;Matt Kandel;D. Anghileri;Francis Oloo;Oscar Kambombe;T. Chibarabada;C. Ngongondo;J. Sheffield;J. Dash
中科院分区：
文献类型：
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作者：
Chengxiu Li;Matt Kandel;D. Anghileri;Francis Oloo;Oscar Kambombe;T. Chibarabada;C. Ngongondo;J. Sheffield;J. Dash
耕地扩张是撒哈拉以南非洲地区促进农业生产的一种常见战略，尽管它往往会导致经济、环境和社会方面的权衡。确保农田的可持续利用及其管理对于改善粮食安全和保护生态系统服务至关重要。为了制定支持国家和地方层面可持续耕地管理的政策和方法，有必要了解耕地扩张（/减少）的空间分布，以及由此导致的耕地生产力变化。这在马拉维这样的SSA国家尤其重要，因为这些国家缺乏对耕地面积和耕地生产力变化的空间明确评估。为了解决马拉维的这一差距，我们使用了多源卫星数据和社会经济数据，结合卫星图像分类和趋势分析，首先量化了耕地面积和生产力的空间变化，其次评估了未来扩展的潜在可用耕地。我们在马拉维发现了不可持续耕地利用的证据，这表现在：(a) 2010年至2019年期间农田迅速扩张（土地面积增加8.5%），其特征是作物种植扩展到高地地区，这表明马拉维的土地稀缺性加剧；(b)未来扩展的潜力有限，大约只有5%的土地仍然是潜在的可用耕地（相当于4671 000公顷）；(c)耕地生产力的总体下降和土壤侵蚀的普遍增加。我们的研究结果强调了采取措施促进可持续农田利用的迫切需要，包括保护现有农田免受进一步退化（如马拉维南部）和改善农田利用规划（如马拉维北部）。
Cropland expansion is a common strategy for boosting agricultural production in sub-Saharan Africa (SSA) even though it often leads to economic, environmental, and social trade-offs. Ensuring sustainable cropland use and their management is critical for improving food security and preserving ecosystem services. To develop policies and approaches that support sustainable cropland management at national and sub-national scales, there is a need to understand the spatial distribution of cropland expansion (/loss), and any resultant changes in cropland productivity. This is especially important in SSA countries such as Malawi, where spatially explicit assessments of changes in cropland area and cropland productivity are lacking. To address this gap in Malawi, we used multi-source satellite data and socio-economic data, combined with satellite image classification and trend analysis, firstly to quantify spatial changes in cropland area and productivity, and secondly to evaluate potentially available cropland for future expansion. We found evidence of unsustainable cropland use in Malawi, which was demonstrated by: (a) rapid cropland expansion between 2010 and 2019 (increase 8.5% of land area), characterized by an expansion of crop farming into upland areas which indicate increased land scarcity in Malawi; (b) limited potential for future expansion, as approximately only 5% of the total land remained as potentially available cropland (corresponding to 4671 000 ha); and (c) an overall reduction in cropland productivity and a prevalence of increase in soil erosion. Our findings underscore the urgent need for taking measures to promote sustainable cropland use, including by protecting current cropland from further degradation (e.g. Southern Malawi) and improving cropland use planning (e.g. Northern Malawi).