ORGANIC ENDIVES ROOTS
Three types of production are defined according to the sowing and pulling-out periods: – sowing in the 2nd fortnight of April under non-woven tarpaulin with a very early pulling-out objective (15 August to early September). This sowing is not recommended in organic farming because false sowing is limited and weeding is made more difficult. – early May sowing for early harvesting (early September to mid-October). The roots are forced after a week in cold storage. The withering technique allows a gain of maturity without any refrigeration system. – normal sowing in May (sometimes early June) for pulling up at maturity (late October to November). The roots are forced immediately or put into cold storage.
The coming back must be at least 5 to 6 years and its place is regulated at the end of the rotation. Crops such as peas, beans, rape, carrots, tobacco and potatoes maintain endive parasites and should be avoided. The endive must be kept away from organic matter inputs. The previous one is generally a cereal whose straws are removed or finely ground and incorporated.
The soil preparation for sowing will be of the beetroot type, but with an even finer and more compacted seedbed. The density varies from 250 to 400,000 seeds/ha in order to obtain final stands of 150,000 (very early pull-out) to 300,000 (pull-out at maturity). As the endive seed is very small, sowing should be carried out at a regular depth of 0.5 to 0.7 centimetres using a precision seed drill specific to vegetables.
Sowing date: around the 2nd half of May in order to allow time for false sowing.
Variety choice: it is determined by two factors: the forcing time and the soil properties. About the planned forcing period, 3 groups of varieties are identified: early varieties with short cycle (October-November production), normal varieties (December to mid-February) and late (March-April).
Varieties are also differentiated by their need and sensitivity to nitrogen: we therefore use a distinction between “sensitive”, “tolerant” and “preferential” varieties. For sensitive varieties, an excess of nitrogen leads to a decrease in quality and a risk of bacterial forcing, while on the other hand, a lack of nitrogen penalizes the productivity and quality of so-called “preferential” varieties.
Nitrogen fertilization is rarely practiced because the soil alone provides the nitrogen requirements of the crop. The choice of variety should be dictated by a 90 cm nitrogen balance carried out at the end of winter. The requirements for other mineral elements are estimated as follows:
P2O5 : 80 kg/ha K2O : 250 kg/ha CaO : 50 kg/ha MgO : 25 kg/ha
Weeding is always a delicate issue because its success depends on weather conditions. Most of the operations are mechanical and depend on the drainage of the soil. Note that thermal weeding is an interesting alternative but still too underused, though it saves time by limiting manual passages. On average, the time spent on manual weeding is considered to decrease by 100 h/ha when a previous thermal treatment is carried out.
Successful weeding requires a set of methods that can be applied independently of each other or in combination:
- Rotation: frequently placed at the end of the rotation for fertilization purposes, the crop is often dirtying if weeding is not controlled. On the other hand, it can be considered as cleansing in view of the many interventions it triggers.
- Choice of variety: it is the quality of the seed that is important. A variety that lifts quickly is more resistant to weed competition. The use of a P17 type tarpaulin often results in a fast and homogeneous lifting that facilitates weeding.
- False sowing: the method consists in preparing a seedbed to germinate weed seeds, which will then be destroyed by a light harrowing. This method can be used several times if weather conditions allow it and in the case of late planting.
- Harrowing: carried out with a spiked harrow, this takes place when the endive reaches the 2 true leaves stage. Harrowing should not be too aggressive and the forward speed slow so as not to break the still fragile pivot, and not to cover the endive with earth. At later stages, harrowing is always possible and recommended. It is possible to pass through the seedling for greater efficiency on the row.
- Hoeing: practiced alone or in combination with harrowing, it helps to control perennials. It can be carried out as soon as the rows appear as many times as necessary up to the ground cover. The hoeing cord left by the discs can be destroyed by harrowing perpendicular to the spiked harrow, finishing the weeding over the entire ground.
- Thermal weeding: the operation consists in creating a thermal shock on the weeds by a passage of heat, which will coagulate the proteins or burst their cells, thus causing the destruction of the plant. This method makes it possible to weed locally on the row when the soil drainage conditions do not allow the use of power tools.
Burning stage: from the 1st true leaf stage of the endive. There is no impact on the quality of the final chicory. At this stage, growing conditions are required in the days following the burning. The best control of weeds is at the 2 to 3 true leaves stage of the endive.
- Manual weeding: it is often required in organic farming. However, it can be very limited if mechanical techniques have been successful or if thermal weeding has been carried out. On the other hand, in the case of dirty plots where manual work is needed, the time required can vary from 150 to 250 h/ha in 2 passages. The staggering of sowing dates avoids a work peak.
The endive is a hardy plant, especially if you choose the right varieties. The number of interventions is often limited or null. In case of an incident, the means of control are as follows, in particular for the main parasite, Sclerotinia:
Parasite / Active substance / Conditions of use
Sclerotinia sclerotiorum / Coniothyrium minitans / Fall and/or Spring Application Rate: 2 to 4 kg/ha
Slugs / Ferric phosphate / 50 kg/ha in full
/ Phasmarhabditis hermaphrodita
/ Ferric phosphate / 7 kg/ha
Noctuaries / Bacillus thurigensis / 0.75 l/ha
Oidium / Sulphur 7.5 kg/ha produced at 80%.
/ Sweet orange essential oil 3 l/ha
Bacteriosis / Copper hydroxide / 3.5 kg/ha with lots of water
The decision to pull-out can be confirmed by a maturity test. This depends on the weight of the roots, the percentage of dry matter, the total nitrogen and nitric nitrogen content. The roots must be received quickly to be placed in a cold room or in layer, within 48 hours. The roots that remain in heaps quickly heat up with a development of diseases.
Root reception: After removal, the roots are dug up to remove the earth responsible for
health problems and gain in storage volume. At the same time as digging up, it is recommended to remove roots smaller than 3 cm and larger than 6 cm by calibrating. This operation saves space in storage and saves time during the planting phase.
Roots can be preserved:
- in small piles or pallet boxes at room temperature for a maximum of 1 to 2 months depending on outside temperatures. This technique is not recommended in organic farming because it is too random.
- in layers for 2 to 3 months.
- in boxes with peat (2 to 3 months). The roots can be preserved by planting them in boxes previously filled with 6 to 8 cm of moistened forcing substrate. The boxes will be protected from drying out and freezing and then placed directly in the forcing trays.
- in a cold room. Before the boxes are placed in the cold room, the roots must be kept at outside temperature for 36 to 48 hours so that the wounds caused by tearing and reception can heal. Cold damage occurs when the root drops below -2.5°C.
Root planting: In case of bacterial risk of Erwinia carotovora, especially in early forcing, an application of copper hydroxide on the crown is recommended (5 g/m² of Kocide® 2000). The application of lithothamnium or talcum powder on the crowns reduces the humidity and therefore the conditions for the development of bacterial diseases.
Layer forcing: Layers are strips of soil about 12 metres long by two metres wide located outside or under a hangar.
The soil is worked and enriched each year with manure or an organic amendment. Each layer has an irrigation system and an underfloor heating system.
The planted roots are covered with a canvas, a tarpaulin or more frequently arched sheets, which are themselves insulated with straw and a tarpaulin. The heating (beginning of forcing) is carried out from 1 to 10 weeks after planting at a decreasing temperature depending on the period.
Irrigation of about 20 mm/m² is carried out at planting followed by 4 to 5 irrigations at the same rate during the three weeks of forcing. Tensiometers and thermometers are used to check the forcing conditions.
Forcing in room:
- a) Description: The forcing room is a dark and thermally insulated enclosure. Inside, the trays are stacked in piles and the piles aligned in rows. A row corresponds to a day of forcing and therefore harvesting.
The room is equipped with:
- an internal ventilation system, allowing the air to be homogenized at all points. Whether independently or integrated into this system, many rooms have one or more air conditioning units associated with a setpoint thermostat.
- an irrigation system for the forcing trays, allowing the water to be conveyed to the tray at the top of each stack. In conventional systems, water flows by gravity from one tray to another and from one pile to another, while the excess water is returned to the general supply tank. In organic farming, it is better to bring the water bin by bin or, failing that, pile by pile without recycling through the main tank in order to avoid any contamination of pathogens. The use of forcing trays with water tank avoids the need for an irrigation system.
- an air humification system by misting for rooms that do not naturally obtain a high hygrometry level.
As irrigation water cannot contain fertilizer, the roots must be forced by a substrate authorized in organic farming (vermicompost, peat, fertile soil, etc.) to which organic fertilizers can be added in small quantities. Hydroponics (water solution + fertilizer element) is prohibited. Therefore, the forcing room is a place where the ambient parameters “air” and “water” must be checked and monitored the most possible.
- b) Forcing process: The water and air temperatures must be such that chicory can be formed within 21 days. Each batch requires a given temperature which tends to decrease as the roots evolve in conservation.
Some existing references indicate that organic fertilizers, rich in ammoniacal nitrogen, cause the blue heart of the endive. This is why chicory is often forced on a mixture based on black peat + lithothamene + organic manure (green waste, guano, feather meal, vermicompost, etc…). Feather meal mixed with black peat with lithothamnium causes less “blue stain” than the use of guano or castor oil cake. Vermicompost mixed 20% with peat and lithothamnion seems to give good results. In all cases, the addition of lithothamnium (320g/100l of peat) is essential to neutralize the acidity of black peat.
PRICES OF ENDIVES
There are few references in organic endive production. The stated figures are often extrapolated from conventional cultivation mainly for the forcing part. Depending on the marketing method, a distinction must be made between wholesale prices (3 €/kg) and direct selling prices (4 to 6 €/kg).