ABSTRACT

Land degradation threatens food production especially in smallholder farming systems predominant in sub-Saharan Africa. Monitoring the effects of agricultural land uses is critical to guide sustainable intensification (SI). There are various indicators of sustainable land use (SLU), but conventional methods to quantify their metrics are complex and difficult to deploy for rapid and large-scale assessments. Considering that SLU indicators are dependent on agricultural practices, which can be rapidly identified and quantified, we propose a framework for SLU assessment that includes indirect quantifications of prioritized indicators (crop productivity, soil organic carbon (SOC), acidification, erosion, nutrient balance) using agricultural practices; and a SLU index derived from the integration of these indicators. The application of the framework to a case study, consisting of 1319 farm plots in Tanzania, reveals that SOC and N balance were the main contributors to the SLU gap. Only 2.2% of the plots qualified as being used sustainably. The framework proved to be sensitive to practices commonly used by farmers, thus providing an opportunity to identify practices needed to revert land degradation. Further application of the framework as a decision-support tool can enhance the efficiency of SI investments, by targeting practices which effectively enhance food production and preserve land.

摘要

土地退化威胁到粮食生产，尤其是在撒哈拉以南非洲占主导地位的小农耕作系统中。监测农业土地利用的影响对于指导可持续集约化 (SI) 至关重要。可持续土地利用 (SLU) 有多种指标，但量化其指标的传统方法很复杂，难以部署用于快速和大规模的评估。考虑到 SLU 指标依赖于可以快速识别和量化的农业实践，我们提出了一个 SLU 评估框架，其中包括对优先指标（作物生产力、土壤有机碳 (SOC)、酸化、侵蚀、养分平衡）的间接量化使用农业实践；以及综合这些指标得出的SLU指数。将该框架应用于由坦桑尼亚 1319 个农场组成的案例研究表明，SOC 和 N 平衡是 SLU 差距的主要贡献者。只有 2.2% 的地块符合可持续使用条件。事实证明，该框架对农民常用的做法很敏感，从而为确定恢复土地退化所需的做法提供了机会。该框架作为决策支持工具的进一步应用可以通过针对有效提高粮食生产和保护土地的做法来提高 SI 投资的效率。从而为确定恢复土地退化所需的做法提供了机会。该框架作为决策支持工具的进一步应用可以通过针对有效提高粮食生产和保护土地的做法来提高 SI 投资的效率。从而为确定恢复土地退化所需的做法提供了机会。该框架作为决策支持工具的进一步应用可以通过针对有效提高粮食生产和保护土地的做法来提高 SI 投资的效率。