Andrew Cartmill

Subirrigation of containerized vegetable crops is a promising strategy to increase water and fertilizer use efficiency. However, the nutrient solution may cause salts accumulation in the substrate top layer. The objective of this study was to determine the effect of nutrient solution concentration in container-grown tomato under surface drip-irrigation and subirrigation. The plants were irrigated with solutions at concentrations of −0.072, −0.058 and −0.043 MPa (100%, 80% and 60% of Steiner's nutrient solution, respectively). Except at the highest concentration, the greatest yields occurred in subirrigated (10.6 kg plant −1) compared to drip-irrigated plants (9.5 kg plant −1). In drip-irrigated plants, yield was higher with the highest solution concentration. The increased yield in subirrigated plants at low solution concentrations was related with increased fruit N and Ca content. The higher accumulation of N, P, K and Ca demonstrates that subirrigation allows for increased nutrient use efficiency, particularly when using nutrient solutions of low concentration. Water use efficiency was markedly increased in subirrigated tomato, as 300 to 460 g of fruit L −1 were produced, compared to 50 g L −1 in drip-irrigated plants. Our results indicate that subirrigation is a feasible system for soilless-cultivated tomato provided the nutrient solution is reduced to a 60% of the total concentration.