Crop Guide: Tomato

1. Tomato crop guide: Dynamics of nutritional requirements

Nitrogen and potassium uptake is initially slow but rapidly increases during the flowering stages.

Potassium is peaking during fruit development, and nitrogen uptake occurs mainly after the formation of the first fruit. (Figs. 5 and 6).

Phosphorus (P) and secondary nutrients, Ca and Mg, are required at a relatively constant rate, throughout the life cycle of the tomato plant.

Figure 5: The uptake dynamics of the macro- and the secondary nutrients by a tomato plant

(Source: Huett, 1985)

Uptake rate (g/plant)

Figure 6: Daily uptake rates of plant nutrients by processing tomatoes yielding 127 T/ha

(Source: B. Bar-Yosef . Fertilization under drip irrigation)

Uptake rate (kg/ha/day)
	Days after planting

As can be seen in figures 5 and 6, the greatest absorption of nutrients occurs in the first 8 to 14 weeks of growth, and another peak takes place after the first fruit removal. Therefore, the plant requires high nitrogen application early in the growing season with supplemental applications after the fruit initiation stage. Improved N use efficiency and greater yields are achieved when N is applied under polyethylene mulches via a drip irrigation system. At least 50 % of the total N should be applied as nitrate-nitrogen (NO3- ).

The most prevalent nutrient found in the developed tomato plant and fruit is potassium, followed by nitrogen (N) and calcium (Ca). (Figures 7 and 8)

Figure 7: Element composition of a tomato plant

(Atherton and Rudich, 1986)