Effects of Water-Saving Technologies on the Establishment and Reproductive Phenology of Five Crop Species Under Rain-Fed Conditions on Floreana Island (Galápagos)

Water scarcity is a major constraint to agricultural production on small oceanic islands, where freshwater availability is naturally limited and production systems depend heavily on rainfall. In the Galapagos Islands, agriculture plays an important role in local food supply and rural livelihoods, yet increasing climatic variability has intensified water-related constraints. Floreana Island is particularly vulnerable, as agricultural production depends almost entirely on rainfall following the deterioration of its natural freshwater sources. This study evaluated different combinations of water-saving technologies (Waterboxx®, Growboxx®, and Hydrogel) and crops against controls, cultivated against on Floreana Island: two annual vegetable crops (tomato and pepper) and three fruit crops (papaya, mango, and tangerine). Early growth rate was assessed during the establishment period (90 days for tomato and pepper and 150 days for fruit crops) using linear mixed-effects models. Survival was evaluated using Kaplan–Meier analyses, and Cox proportional hazards models were used to assess the timing of first flowering and fruiting events. All models were made at the individual species level while controlling for within-site variation. Waterboxx® was associated with reduced early growth in tomato and pepper and a marginal reduction in mango, but with increased growth in tangerine. Waterboxx® was also associated with increased survival in tomato and tangerine but reduced survival in pepper. It delayed fruiting in tomato and both flowering and fruiting in papaya, while showing a marginal tendency toward earlier fruiting in pepper. Hydrogel delayed flowering in pepper without significantly affecting early growth or survival, whereas Growboxx® reduced early growth in tomato and survival in pepper. Due to imbalance in the sample sizes bootstrap analyses were done, which generally supported the direction of the observed treatment responses, although statistical support was retained for only a subset of them. Overall, responses to water-saving technologies depended on both crop species and the component of plant performance evaluated, with no single technology consistently producing favorable responses across crops. These findings support crop-specific selection of establishment technologies under water-limited island conditions.