Sustainability of organic zucchini in Mediterranean environment: an on-farm experimentation.

Background: Excess inputs are commonly applied to high-value crops to ensure high performance. This study hypothesizes that farmers can reduce inputs without compromising yields and aims to investigate the effects of varying irrigation and fertilization strategies on two zucchini genotypes ('Logos' and 'Atlantis') organically grown under greenhouse tunnels in southern Italy over two seasons. Conducted on a large scale within an on-farm experimentation framework, this research compared two different irrigation volumes (the farmer's experience-based volume vs. a 25% reduction) and two nitrogen fertilization rates (the farmer's usual rate vs. a ~50% reduction).

Results: An average reduction of 550 m³ ha^-1 of irrigation water led to a yield decrease of 3.0% (57.4 vs. 55.7 t ha^-1), while a reduction in nitrogen fertilization (-156 kg ha^-1 of N) resulted in a yield decrease of 3.3% (57.5 vs. 55.6 t ha^-1). In light of these modest yield reductions, significant increases in irrigation water productivity (+33%) and fruit nitrogen use efficiency (+75%) were observed. The physical and color characteristics, along with the mineral composition of the fruits, were primarily influenced by the growing season and, to a lesser extent, by the genotype, while inputs had little to no effect.

Conclusion: This paper offers insights into sustainable zucchini production, demonstrating that resource-efficient farming can respond to environmental and economic challenges while maintaining satisfactory yields and fruit quality. The study highlights the effectiveness of a participatory approach as a means to generate reliable results for researchers while also providing outcomes that are directly applicable to farmers. © 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.