Production of tomato plants grown in a greenponics system under automated irrigation management

Cultivation of tomatoes in greenponics offers an alternative for organic production. This study evaluated the performance of tomatoes grown in greenponics in the field, with plants grown in planting-pits filled with non-composted biomass from grass clippings (Paspalum notatum) (GC) and tree-legume leaves (Gliricidia sepium) (GLI). Effects on water use efficiency (WUE) and residual nutrients in the substrate recovered from the planting-pits at the end of the production cycle were also evaluated. Treatments in 2023 were: T1, soil + fermented Bokashi compost (control); T2, 100% GC; T3, 100% GLI + thermophosphate (Y); T4, 100% GC+Y; T5, 75% GC + 25% GLI+Y; T6, 50% GC + 50% GLI+Y; and T7, 75% GLI +25% GC+Y. In 2024, T6 was tested under different watering regimes. Drip irrigation with sensor-based management was used. In 2023, after 10 harvests, yields ranged from 79.0 (T2) to 121.1 Mg ha−1 (T6) and WUE from 17.9 to 27.3 kg m−3. The total yield in T6 was 44.9% higher than in the control, with 37.6 commercial fruits plant−1 (NCF) and 148.8 g average fruit weight. The superior performance in T6 was likely linked to higher nutrient input, with N and K supplies in T6 being approximately 3 and 10 times higher than in T1. Low residual nutrient concentrations in the recovered substrate indicated near-complete biomass mineralisation. In 2024, after 6 harvests, yields ranged from 94.2 to 107.5 Mg ha−1 with the highest NCF of 39.6 and WUE of 36.0 kg m−3, as estimated by regression models. Results indicated that greenponics can be a viable option for organic tomato production.