A Systematic Review of Drivers and Constraints on Agricultural Expansion in Sub-Saharan Africa

Nugun P Jellason,Adam J M Devenish,Abbie S A Chapman,June Y T Po,Dora Neina,Barbara Adolph,Elizabeth J Z Robinson

doi:10.3390/land10030332

Abstract

Understanding the dynamics of agricultural expansion, their drivers, and interactions is critical for biodiversity conservation, ecosystem-services provision, and the future sustainability of agricultural development in Sub-Saharan Africa (SSA). However, there is limited understanding of the drivers of agricultural expansion. A systematic review of the drivers of agricultural expansion was conducted from 1970 to 2020 using Web of Science, Elsevier Scopus and Google Scholar. Two researchers reviewed the papers separately based on inclusion and exclusion criteria. Fifteen papers were included in the final systematic review. The paper proposed expansion pathways in a conceptual framework and identified proximate and underlying drivers. Population dynamics and government policies were found to be key underlying drivers of agricultural expansion. The proximate drivers include economic opportunities such as agriculture mechanisation and cash crops production, and more troubling trends such as soil fertility decline and climate change and variability. This paper further explores the constraints that have been found to slow down agricultural expansion, including strong land institutions and good governance.

Highlights

Population growth and rising incomes are generating ever greater demands on agriculture to supply food, fuel, fibre, and animal feed [1,2]
The rest of the paper is divided into six sections: we explore the global level drivers and constraints to agricultural expansion; in section three, we describe the conceptual framework and the systematic review methodology; section four presents the results and findings of the systematic review; section five discusses the implications of the findings for future agricultural land-use; and, section six concludes
The fifteen papers identified through the systematic review comprise two studies each that focus on Ethiopia and Ghana; two that are multiple country studies; and one study each that focuses on Angola, Nigeria, Senegal, South Africa, Tanzania, Uganda, and Zambia

Summary

Introduction

Population growth and rising incomes are generating ever greater demands on agriculture to supply food, fuel, fibre, and animal feed [1,2]. Agricultural expansion, defined as the conversion of natural vegetation to land-use for agriculture [7], that occurred in the 1980s and 1990s has resulted in an increase in the area under food production in SSA and increased opportunities for income-generation and food security [6]. This expansion may threaten a wider array of provisioning and regulating ecosystem services that are provided by areas of natural vegetation [6,11,12,13,14,15]. Given the increasing pressure on agricultural land and the impacts of agricultural expansion on livelihoods and ecosystem services, a better understanding of the drivers of agricultural expansion in SSA, where a driver in this context is defined as any factor that alters “an aspect of an ecosystem” [15,16], is both imperative and timely

Methods

Results

Discussion

Conclusion