Heterogeneous effects of agrochemical use, land availability, and population growth on cocoa yields in Nigeria: Evidence from a modified cross‐quantile regression

The cocoa ( Theobroma cacao L.) sector in Nigeria has experienced declining productivity despite its historical importance and favorable agroecological conditions. Persistent challenges, including inefficient agrochemical use, land constraints, and rapid population growth, continue to hinder yield improvement, yet their effects across different farm performance levels remain poorly understood. This study examines the impact of agrochemical practices, arable land availability, and population growth on cocoa bean yields in Nigeria from 1990 to 2023 using a modified cross‐quantile regression (MCQR) approach. Unlike conventional regression models that estimate average effects, the MCQR approach captures heterogeneous and distribution‐specific relationships, enabling the analysis of how these factors affect low‐, medium‐, and high‐performing farms differently. The results show that nitrogen fertilizer and insecticide use often exert negative effects at higher yield levels, suggesting inefficiencies or diminishing returns associated with excessive input application. In contrast, arable land availability consistently exerts a positive influence across all quantiles, while population growth demonstrates mixed and context‐dependent effects. Overall, the findings highlight the need for targeted policies that promote efficient resource use, sustainable cocoa production, and improved farm management practices in Nigeria.