High field yields are obtained on freely drained soils where water is not limiting.
Crop nutrition is also essential for increasing tomato yield.
Nitrogen is one of the most important nutrients required for optimum crop growth and high tomato crop yields. Tomato crops remove around 2.2-2.4kg for every tonne of fruit produced, therefore high rates of 250kg/ha or above are needed for average 100t/ha field crops. However, too much nitrogen can depress tomato yields, so it is important to confirm rates following local trials.
Correct form is critical, ammonium can restrict growth and adversely affect overall quality.
Phosphorus is important for early growth and root development of the establishing seedling. It is also essential at the stage of fruit set. In soils with low available phosphorus, fertilizer phosphate increases tomato fruit yield and ripening, reducing the number of rejected fruit at harvest.
Tomatoes have a relatively high potassium requirement with over 300kg/ha of potassium typically being utilized. High potassium levels provide high tomato yields. Balance to other nutrients such as calcium and magnesium is also important.
Calcium is required in the tomato for canopy growth, root development and yield. Mid-season availability is critical for high tomato crop yield. Continuous supply throughout the season is also important, balanced along potassium and magnesium.
Sulfur is important for overall tomato yield. Sulfur application is required throughout the whole season. Soils are often sulfur-deficient: Foliar applications can be more effective than soil applied fertilizer.
Unavailability of any micronutrients will limit tomato yield. It is important though to make sure that manganese and boron are not present in excess as this can lead to toxicity and restricted growth. The most important micronutrient is boron, which if in short supply, will result in fruit with corky areas on the shoulders and in severe deficiency instances may restrict fruit formation.