In the case of application of the technique with the presence of the crop on the field, two different methods can be used depending on the type of crop to be treated and the degree of growth of the same.

FULL SURFACE TREATMENT

The technique of flame treatment on the whole cultivated area in the presence of plants is applied whenever the plants themselves, often shrubs or are by their nature very resistant to heat or have quick recovery capacity due to the presence of roots with considerable nutrient reserve.

In the case of shrub plants, the technique is applied on woody plants that are normally perennial and stand out from the tree by their generally lower height and by the ramification starting from the bottom, from the base of the plant, rather than from a distinct trunk. In other words, a shrub does not have a main trunk well defined as a tree, but rather a series of branches that originate from the base. In this type of crop the part that is harvested are the leaves.

 

Examples of these crops may be the

• Medicinal plants whose leaves are cut off such as: thyme, sage, rosemary, tea plant, myrtle, etc.
• shrub plants d whose flowers are cut as: roses, peonies, hydrangeas, lilac, jasmine, etc.

In the case of perennial plants, the technique is applied to plants that are appreciated for their flavour, aroma and culinary properties, and their leaves can be harvested repeatedly, even in an automated manner, during the growing season as the plants continue to regenerate.

These crops have enlarged roots that store carbohydrates, vitamins and minerals, which the plants use during periods of growth or in stressful situations.

Some examples of perennial plants whose leaves are collected are: laurel, mint, parsley, chives, wild celery, sorrel, acetosella, wild spinach, portulaca, borage, wild chicory, dandelion, etc.

TREATMENT LOCATED ON FILE

The heat treatment with flame can be carried out in a localised manner on seed rows or crop transplants. The intervention is carried out by operating with the same number of rows that were used in the sowing or transplanting phases. Often the operation is carried out with the aid of a weeder that allows to perform simultaneously, when there is need, the operation of weeding between rows. The minimum distance between rows shall not be less than 30 cm.

This operation must take place when the development of the crop to be treated makes it resistant to heat; the height of the plant should be 10 – 15 cm. variable depending on the type of culture and its resistance to heat.

The work is carried out in a localised manner on the row and the working width of the flame is adjusted according to the size of the plant to be treated.

Each burner is equipped with an air jet air jet channelled over the flame produced by the burner in order to control the inflow of heat directed onto the crop. The function of the air jet is to prevent heat from rising towards the apex of the plant, which would certainly cause damage. The heat-affected area on the row may be up to a maximum of 40 cm wide.

For each row of product there are two burners that are directed directly towards the base of the plant to be treated (height of the intervention of the flame from the ground less than 5 cm).

The surface area to be treated depends on the type of crop to be treated, the width between rows of the product and the working speed. Normally the working speed never falls below 3 km/h

LPG/hectare consumption is also linked to the parameters mentioned above.

Post-emergence heat treatment cultivation is often essential not only for weed control but also for combating fungal diseases and insects, as in this case it involves treating fungal spores and small insects that are not resistant to average amounts of heat, even for very short periods. Crops in the field that are exposed to these controlled heat levels during flame heat treatment do not suffer any damage.

See also: APPLICATION TECHNIQUE

See also: ELIMINATION OF HARMFUL INSECTS

See also: MEDICINAL PLANTS

See also: GARLIC – LEEK – ONION

See also: CORN – SUNFLOWER – SOY