Cultivation techniques

Development of sustainable cultivation techniques :

  • Define cultivation directives for a controlled quality and mastered production costs
  • How to successfully achieve the drilling ? When and how to plant ? Which fertilization ? When to harvest ?
  • Which disease or pest is it ? How to get protected ?
  • How to best stabilise the harvest ? (directives for drying and storage)

Exemples

Incidence of the harvesting stage (white Genepi )

The floral stems of white genepi, Artemisia umbelliformis, are in great demand, essentially for the production of alcoholic beverages. The phytochemical quality of the harvested material is assessed by the analysis of volatile substances (essential oil) and the determination of bitter principles, especially the costunolide that represents about 80 % of the sesquiterpenic lactones.

The considerable harvest quality fluctuation lead to investigating the role of the maturity status at harvest. So the plants were harvested at regular intervals during the whole flowering period. Losses up to 60 % were noted for essential oil and costunolide, within one week. An optimal stage, i.e. the beginning of flowering, could that way be defined to obtain a high quality harvest.

Effect of altitude - Edelweiss (Leontopodium alpinum)

The environmental parametres (soil, climate, altitude, …) together with the varietal aspects and the cultivation techniques, are the main factors responsible for the internal quality of plants. The potential effect of altitude on the plants’ phytochemical composition, although frequently mentioned, had not been studied very much. It is indeed a difficult factor to pinpoint, as it is tightly related to other variables such as rainfall, soil nature, temperatures, wind, …

In tight cooperation with two institutes, Mediplant set up a one of a kind study, with edelweiss as a model. That way, two characterized edelweiss genotypes were cultivated in containers with an identical substrate, on an altitudinal transect ranging from 500 to 2400 m. a.s. in central Valais. The follow-up of the plants’ development  and their phyto-chemical composition, but also the measurements of the anti-oxydant and anti-radical activities lead to very interesting conclusions. The results show indeed that the cultivation site (temperature, rainfall) would have more influence than the altitude (e.g. UV radiations) on the induction of the plant’s stress and its anti-oxydant substances production.

Drying and storage (Artemisia annua)

The stabilisation of vegetal material harvested for medicinal and aromatic plants is generally carried out through a drying operation. Important questions arise such as how to prepare the plant before drying ? At which temperature to dry ? How and how long to preserve the plants after drying ? These questions come with a double requirement, a qualitative one (the plant) and an economical one (energy costs). For the annual wormwood, the stake is very important with several thousands tons leaves harvested each year.

After several years trials on temperatures and relative air humidity levels, we have now gained a good knowledge of the optimal drying  and preservation parameters.

Diseases and pests

These sanitary problems often come together with any new culture of medicinal or aromatic plants. It goes along with the selection and putting into culture works.

The knowledge of the incriminated bio-offender (fungus, virus, insects, …) is necessary in order bob e able to adapt the selection programmes (research of tolerant varieties) as well as to define fight strategies to reduce economical losses.

With the support of specialists we are regularly lead to set diagnosis.