Salinity and tomato production

Tomatoes are moderately tolerant to salinity and will grow in an EC up to 2,5mS cm-1 without yield reduction. Above this EC level yields will be gradually reduced, although the reduction will vary with variety.

EC level, type of salinity, and the balance between the nutrients in solution will all influence the quality of the harvested fruit.

A high EC will:

• Reduce fruit size (see graph Salinity and Fruit Size). Adding potassium will correct this problem.
• Increase sugar (see graph Salinity and TSS) as well as the acid content of the fruit, improving taste.
• Increase fruit firmness and peel thickness improving shelf life.
• Reduce the mealiness of the whole fruit therefore improving texture.
• Increase pigment content and so enhancing color. Care is needed though, because using solutions with an EC above 5 will result in pigment concentrations declining again.

Using sodium chloride to increase EC has been found to improve tomato taste, flavor and firmness. However too much sodium chloride will be toxic to the tomato plant and reduce growth (see graphs Salinity and Leaf Retention and Salinity and Plant Height) severely reducing yield.

Increasing potassium and calcium in plants under sodium chloride stress will improve the growth and yield of tomatoes.