Assessment of social demand heterogeneity to inform agricultural diffuse pollution mitigation policies

Agroecosystems provide several agroecosystem disservices, among which diffuse nutrient pollution is one of the most significant, mainly due to its negative impacts on surrounding ecosystems, such as coastal ecosystems. Therefore, the implementation of agricultural measures to mitigate nutrient pollution might become a way to overcome this environmental challenge. However, proper implementation requires both a cost-effectiveness assessment and social support. This paper aims to value the social demand for agricultural measures to mitigate nutrient pollution and the benefits gained in the surrounding ecosystems from their implementation. Additionally, the demand preference heterogeneity is assessed. Measures proposed by a law intended to mitigate diffuse nitrate pollution in the Campo de Cartagena catchment area (south-eastern Spain) and thereby restore one of the main coastal lagoons in the European Mediterranean Sea, the Mar Menor, are used as a case study. A choice experiment and latent class mixed logit were employed to disentangle heterogeneous social preferences. Despite the fact that preference heterogeneity was revealed regarding the proposed agricultural measures, strong preferences linked to the restoration of the Mar Menor were shown by all the distinct classes. The socioeconomic benefits derived from the measures along with the expected environmental benefits from the restoration of the surrounding ecosystems exceed the farmers' costs for their implementation. Consequently, the results provide guidance to policy makers in the establishment of socially supported strategies for agricultural nitrate pollution mitigation.