Land Degradation Neutrality, Agroecological Transition, and Farmer Welfare in Nigeria’s Middle Belt: A Systems Modelling Approach

Nigeria's Middle Belt, spanning the North Central geopolitical zone across Benue, Kogi, Plateau, Nasarawa, Niger, and Kwara States, is undergoing accelerating land degradation driven by deforestation, intensive tillage, erosion, and declining soil organic matter. The land degradation neutrality concept, framing the policy goal of no net loss of productive land by 2030, requires modelling the systems-level interactions between land use change, soil health trajectories, crop productivity, and farmer welfare across diverse farming system types. This study applies a systems modelling approach combining a biophysical soil carbon and productivity model with an agricultural household economic model to analyse land degradation neutrality pathways and the welfare implications of agroecological transition strategies in Nigeria's Middle Belt. Biophysical model parameterisation draws on soil survey data from five states, historical land use change data derived from satellite imagery from 2010 to 2024, and crop yield response functions from experimental trials. The household economic module is calibrated using longitudinal survey data from 400 farm households across three representative farming systems. Scenario analysis compares a business-as-usual trajectory with three agroecological transition pathways of varying ambition and public support intensity. Results indicate that the business-as-usual trajectory generates a 14 percent reduction in crop output by 2040 due to accelerating soil degradation. The highest-ambition agroecological transition pathway, combining conservation agriculture, agroforestry, and integrated soil fertility management, achieves land degradation neutrality by 2035 while increasing average household farm income by 19 percent. Payment for ecosystem services significantly accelerates transition. The study provides an original integrated systems modelling contribution to the land degradation neutrality policy literature for sub-Saharan Africa. Keywords: land degradation neutrality, agroecological transition, systems modelling, Middle Belt Nigeria, farmer welfare