Agriculture yield gap reduction: The interplay of capitals, crop diversity and specialization

Meeting food demand without expanding agricultural land remains one of the greatest sustainability challenges. While crop diversification is often promoted as a strategy for sustainable intensification, its real-world effectiveness under varying socio-environmental conditions remains unclear. We addressed this critical gap by analyzing national-scale yield gap reduction across 105 countries from 1992 to 2021, linking crop diversification "strategies" with forms of capital defined by the Sustainable Livelihood Framework. Using Random Forest model we found that the dominance of major crops is consistently associated with yield gap reduction, especially in countries with strong financial, human, and socio-political capital. Diversification within major crops often has neutral or negative effects. By contrast, broader functional diversity across all crops contributes positively under enabling conditions (high human, financial and socioeconomic capital). These results emphasize the value of agriculture specialization and redefine diversification as a context-dependent strategy, thus providing a framework for advancing sustainable intensification.