Water scarcity is one of the major constraints in agriculture, particularly affecting crop growth and development in arid and semiarid regions. As climate change intensifies the frequency and severity of drought events, there is a growing need for sustainable strategies to enhance crop resilience under limited water availability. Organic amendments such as compost have gained attention for their potential to improve soil health, water retention, and plant stress tolerance. In this line, this study evaluates, in a pot experiment under controlled conditions, the impact of garden waste compost application on tomato (Solanum lycopersicum) growth under varying levels of water deficit (100%, 60%, and 40% of field capacity, FC) in order to simulate optimal, moderate, and severe water stress conditions, respectively. The application of compost significantly enhanced plant growth and biomass accumulation across all the irrigation levels, with the most pronounced benefits observed under moderate water deficit (60% FC). These results suggest that compost amendments can improve plant performance and mitigate the adverse effects of water stress deficit, emphasizing their potential role in promoting water scarcity resilience in sustainable agriculture.

Acknowledgements: This work was supported by the INTERREG-POCTEP Spain-Portugal programme and the European Regional Development Fund through the project FRONTEIRA HUELLA ZERO_2030: POR UNA FRONTERA SUSTENTÁVEL.