Multi-level analysis of nutrient cycling within agro-sylvo-pastoral landscapes in West Africa using an agent-based model

Authored by Benoit Gaudou, Myriam Grillot, Francois Guerrin, Dominique Masse, Jonathan Vayssieres

Date Published: 2018

DOI: 10.1016/j.envsoft.2018.05.003

Sponsors: French National Research Agency (ANR)

Platforms: GAMA

Model Documentation: Other Narrative Flow charts

Model Code URLs: https://www.comses.net/codebases/5608/releases/1.3.0/

Abstract

Livestock-driven nutrient flows are the main sources of soil and crop fertilization in West African agro-sylvo-pastoral landscapes. They result from nutrient recycling between farm activities and the spatial transfer of nutrients within the landscape. ``Extensive{''} systems, based on livestock mobility are tending to be replaced by more ``intensive{''} systems based on in-barn livestock fattening. We built an agent-based model to compare these systems in terms of nitrogen cycling at land plot, herd, household and village levels. Model evaluation, based on field-data from two real contrasted villages, showed that the model satisfactorily reproduces the differences between an ``extensive{''} and an ``intensive{''} system with key parameters such as variability among households and soil fertility gradients. Simulations highlighted bottlenecks along the nitrogen (N) cycle like accumulation of N in manure heaps and housing areas, reducing N recycling efficiency, especially in ``intensive{''} systems. The model can be further used to explore improved agro-sylvo-pastoral landscapes.

Tags

Multi-agent system Decision-Making multi-level modeling soil fertility Simulation-models Crop-livestock systems Nitrogen Biomass flows Crop-livestock integration Nutrient spatial transfers Soil fertility management Global activity model Mixed-farming system Smallholder farmers Phosphorus budget Spatial carbon