Managing saline soil to boost crop yield and halve nitrogen losses

Soil salinity is an escalating global challenge that reduces crop productivity and exacerbates reactive nitrogen (Nr) losses, threatening food security and environmental health. However, the dual impacts of salinity on crop yields and nitrogen cycling remain under-quantified at the global scale. This study aims to quantify how salinity alters nitrogen dynamics and yield outcomes in croplands and to assess the effectiveness of integrated mitigation strategies designed to reverse these adverse trends. We focus on identifying practical solutions that deliver co-benefits for agricultural output and environmental sustainability in saline croplands. For this, we integrate the IMAGE and CHANS models to construct the nitrogen budget for saline croplands worldwide. A pairwise comparison framework was employed to quantify changes in nitrogen flows across saline and non-saline conditions. Additionally, a global database of field-based mitigation strategies and simulated combined interventions to evaluate their effectiveness. Afterwards, cost-benefit analysis was conducted to evaluate the societal benefits of implementing mitigation measures at scale. Our results show that soil salinity increases nitrogen inputs by 13%, exceeding 1 million tonnes per year, while reducing nitrogen harvest by 7% and amplifying Nr losses by 61%. To assess mitigation potential, we compile and evaluate ten categories of salinity management measures, which collectively reduce Nr losses by 58%, equivalent to 1.9 million tonnes annually, while enhancing yield and generating net global benefits of approximately US$12.6 billion. Regional analyses highlight Asia (e.g., China, Pakistan, Indonesia) and the Middle East (e.g., Iran, Egypt, Saudi Arabia) as hotspots for saline croplands mitigation. The study provides an evidence-based framework for integrating nitrogen budgeting with mitigation policy and highlights the importance of prioritizing salinity mitigation policies and enhancing sustainable agriculture management under increasing environmental stressors.