Plant biomass and fruit quality response of greenhouse tomato under varying irrigation level and water quality

The impact of water quality with varying deficit irrigation level on the plant biomass and fruit quality parameters of greenhouse tomato (Lycopersicon esculentum L. cv Izmir) was investigated. A pot-based experiment was carried out over two growing seasons (2017-2018 and 2018-2019). Three water qualities: groundwater, recycled wastewater and an equal mix of both were applied in four irrigation scenarios which aimed to maintain soil moisture levels at 60%, 70%, 80% and 100% of field capacity. A surface drip irrigation system was designed maintaining irrigation frequency of two days. Results showed that both water quality and deficit irrigation significantly affected plant biomass. The fresh fruit weight was rather uniform, ranged from 53.2 to 85.4 gram and found highest in full irrigation. Most of the fruit quality parameters were not significantly affected by water quality.The significantly higher values of total soluble solid (7.87 degree brix), fruit firmness (9.28 kg/cm2), fruit pH (4.24) and vitamin C content (68.33 mg/kg) were measured in treatments maintaining soil moisture content at 60% of field capacity (most water-stressed conditions). Based on these findings, it recommended that by adopting deficit irrigation and maintaining soil moisture at 60% of field capacity, fruit quality parameters can be significantly improved. In contrast, fresh fruit weight and plant biomass were reduced.