Tomato paste is an important industrial agri-product. Tomatoes originated in America but were quickly adopted by Mediterranean and Western cuisines. Peeled, mashed or dried, tomato products can be found everywhere.

Most processing varieties are determinate: they produce a given number of clusters,   stop growing and die. Tomatoes can be seeded or transplanted. It takes 70-110 days from planting to harvest. They are harvested mechanically or manually.

Environment

Climate: Tomatoes require warm, dry weather. Very high or low temperature at flowering will decrease pollination. Summer rain can induce diseases and fruit rot and spring frost can be lethal. 

Soil: Soil should be well-drained and free from soil infestations like nematodes and witch broom. Slightly acidic, fertile soil is optimal.

Salinity in the soil or water can reduce vegetation and yield, but will later increase dry matter percentage of fruits.

Planting layout

For determinate processing varieties, plant density is 3-4 plants per m2, depending on the variety vigor. The distance between rows is adjusted to the available agricultural machinery, from 90cm for single rows to 192cm when double rows are planted.

Water demand

Most growers start planting on a deeply moist soil profile. Plants are irrigated at germination or at the transplanting stage. When the plants start growing, irrigation is stopped in order to control vegetation and enhance deep root development.

At fruit set, irrigation is renewed to help fill the fruit.  At this stage, crop coefficient (Kc) is 0.7-1.0 and irrigation frequency is high.

When the fruit begins maturation, a slight water stress is imposed to increase the dry matter percentage in the fruit. A few days before harvest, irrigation is turned off to allow for convenient harvest. Not earlier, because drying the soil too early can result in leaf abscission and fruit sunburn.

Irrigation

Tomatoes may be irrigated by sprinklers or drip. Most growers prefer the drip system which increases yields and contributes to better foliar health. In some locations, irrigation is started with sprinklers in order to activate herbicides and help during the stand up stage after transplanting. Direct transplanting into the wet soil strip is also common when no chemical activation is needed.

In clay soils, one dripline can serve two rows, spaced at 50 cm apart. In sandy soils, the spacing should be less. The spacing between drip emitters along the dripline ranges between 20cm in sandy soil and 60cm in clay soil.

Fertigation

Tomatoes consume a lot of nutrients. Most can be efficiently applied by fertigation. Fertigation starts at fruit set and lasts as long as the fruit fills up.