Korreltje Zout: A Literature Review of Saline Irrigation

Abstract

Globally, soil salinity and the salinization of water resources is increasing. For plants in particular, this trend could be troubling as saline water and soil can cause ion toxicity, osmotic stress, and nutrient imbalances. However, responses to salinity vary greatly across the Plantae kingdom. In general, three strategies—adaptation, mitigation, and desalinization—can be applied to address these issues. Mediamatic is an arts, science, and cultural organization that is exploring the use of saline water for myriad irrigation projects in Amsterdam, the Netherlands. Their goal is to stop using any tap water to irrigate outdoor gardens and supply an aquaponics greenhouse. Within this context I review the current literature discussing the first two strategies of adaptation and mitigation and make recommendations for adapting Mediamatic to a sustainable and salty future. Overall, while some species of plants, and halophytes in particular, show remarkable resilience to saline conditions, others are very sensitive to salt stress and require special attention. Therefore, plant selection is vitally important to adapting to a saline irrigation system. However, current literature also describes many potential strategies to mitigate these responses to salt stress, allowing a broader range of plants to tolerate high levels of salinity. Most literature focuses on using different soil treatments, such as potassium, gypsum, and bio-organic amendments to alter ion imbalances in the soil and promote uptake of vital nutrients. Further research suggests different irrigation strategies, such as mulched drip irrigation and freshwater flushing of the soil to control the salt levels in the soil. Taken together, I recommend that Mediamatic employ a mulched drip irrigation system that is supplemented with bio-organic soil amendments, while also choosing plants that can tolerate the moderate salinity level of the brackish water in the Dijksgracht with an EC of ~2-5 dS m-1. I also recommend that they increase their rainwater storage capacity for use in the aquaponics system and for flushing outdoor irrigated areas. Finally, I outline the design of a potential integrated system of all irrigated areas within Mediamatic, where I propose to implement a stage-based halophyte filter.