Manual of Cultivation of Hemp
Manual of Cultivation and First Processing of Hemp
ACCORDING TO THE BIOLOGICAL AND BIODYNAMIC METHOD
Cannabis sativa (L.) is a herbaceous species with an annual cycle, belonging to the Cannabaceae family. Hemp stands out from all other plant species due to the wide range of a particular family of active ingredients: cannahinoids. The flora of the plant normally contains over a hundred different cannabinoids, the best known of which is tetrahydrocannabinol or THC, the only cannabinoid to our knowledge with psychoactive properties. Industrial hemp varieties are distinguished by their very low THC content, but regardless of the THC level, all varieties of ca napa belong to the same species.
Hemp is characterized and appreciated as an agricultural crop for two other properties: the fiber with high resistance and absorbent capacity and the seed with high nutritional value, as it is rich in polyunsaturated fatty acids, vitamins and other bioactive molecules.
Hemp is considered to be one of the oldest known crops
to man. Its first use, in terms of cultivation, dates back to about 12,000 years ago. In China, at the time of Emperor Shennung (2700 BC), hemp was the most important "textile plant" used for the production of ropes, sheets, curtains, carpets, sacks, sails for ships. Its use, on the other hand, as a raw material for the production of paper, seems to date back to more than 2000 years ago. The decline of hemp, which occurred following the Second World War with the profound crisis that affected the textile sector, led, in many regions of Western Europe, to the total disappearance of the crop, which was followed in the first 90s of the last century, a renewed interest with its gradual re-introduction into the crop systems of the European Union.
Hemp today can be used for three types of consumption: industrial, medical, personal. This manual only deals with the cultivation of industrial hemp, ie plants a
low THC content. Generally in Europe the limit of
THC for industrial hemp is 0.2%.
ITALIAN LEGISLATION ON INDUSTRIAL HEMP: CULTIVATION RULES
Industrial hemp in Italy is governed by the law
of 2 December 2016, which introduced important news to protect growers.
These in summary are the salient points:
The law protects only those who cultivate the varieties of hemp admitted in the European catalog of varieties of agricultural plant species, all with low THC content (Article 1); 1
To cultivate these varieties it is not necessary to ask for authorization (Article 2);
The permitted uses are as follows (Article 2, paragraph 2):
production of food and cosmetics,
production of semi-finished products for industries and craft activities,
green manure practices,
organic material for bioengineering or green building work,
f crops for teaching and research activities,
g. crops destined for horticulture,
and finally energy uses for self-production.
The grower's only obligations are to keep the tags of the seeds purchased (for at least 12 months) and the purchase invoices (Article 3);
Controls, sampling in the field and subsequent analyzes by the police must be conducted according to the criteria of European legislation and in the presence of the grower, who must be issued a sample taken for any counter-tests (art. 4);
In the event that the control shows a THC content higher than 0.2%, 2 but within the limit of 0.6%, the grower is not responsible for any responsibility (provided that he has complied with the criteria we have indicated in points I and 4 - article 4, paragraph 5);
Seizure and possible destruction of crops are allowed only if the THC limit is higher than 0.6% and can only be ordered by the judicial authority; but also in this case the grower who has respected the previous criteria is not responsible for any responsibility (Article 4, paragraph 7).
These are the main rules governing the cultivation of industrial hemp in Italy and its possible uses.
INFIORESCENCES: THE RECOGNITION OF HEMP AS A OFFICINAL PLANT
In the rules of Law 242, which also guarantee a series of protections for growers, there has nevertheless remained a fundamental gap which has so far held back industrial investments in hemp.
In fact, a fundamental part of the hemp plant is never mentioned in the text of the law: the inflorescences.
If in the past industrial hemp was cultivated above all for the fiber and much later, from the beginning of the 2000s, also for the
for food use, today the inflorescences represent the potentially most income-producing part for growers all over the world.
Hemp inflorescences contain over 500 active ingredients, including more than a hundred cannabinoids. Over the past fifty years it has been progressively discovered that many of these substances have an important health and therapeutic value. Apart from THC, the best known and the only one that can give narcotic effects, various other non-psychotropic cannabinoids, starting with Cannabidiol (CBD), the most widespread in the inflorescences of industrial ca napa, are now enjoying increasing importance on the supplement markets. food, cosmetics and pharmaceuticals.
The fact that the law 242 does not name, but does not even prohibit the use of inflorescences, has created an aura of ambiguity in the interpretation of the rule, which among other things recognizes among its uses 'crops for horticulture'. Lambiguity was accentuated by the indication of 0.6% THC as a limit for the grower, which consequently many operators (and a large part of the judiciary) have also considered valid for the trade of hemp-based products. Hence it was born in
2017 the phenomenon of 'can nabis light' with all the contradictions and judicial problems that have developed.
The fundamental obstacle, which prevents full and unambiguous recognition of the legitimacy of the use of industrial hemp flowers, is the inclusion, still in force in Italian and international legislation, 4 of hemp in the lists of narcotic substances "with the exception of hemp grown exclusively for the production of fibers or for other industrial uses ... permitted by European Union legislation "'5.
A good step forward has been made by a recent decree
of the Minister of Agriculture, who in a list of offi cial plants for insurance premiums mentioned the "inflorescence hempasative," intended for "extractive uses" .6
Recognizing hemp as a medicinal plant, including its inflorescences, it should now be legitimate to produce - by the farmer himself or by third parties - extracts, essential oils and tinctures from industrial hemp flowers, as long as they have a THC lower than 0.2%, grown according to Law 242/2016, and in compliance with the Good Agricoltu ra! Collecting Practices (GACP), and marketed according to the specific regulations of the sector.7 The problem is that at the same time the official list of medicinal plants has not been approved, which should include hemp and on which one has been working for almost two years. commission of experts appointed by the Ministry of Agriculture.
CHOICE OF VARIETIES
AND CULTURAL TECHNIQUES
Based on the regulatory framework described, today from hemp grown according to the rules of law 242/2016 it is possible to use potentially all parts of the plant:
stems to obtain fibers and sheaves,
seeds for food use (or for reproduction on the basis of a contract with an authorized seed company),
biomass for phytoremediation, green manure or for energy uses,
and also the roots of hemp, which have anti-inflammatory and pain-relieving properties known since ancient times, as they are rich in active ingredients (but without THC), including triterpenoids, monoterpenes, alkaloids and sterols.
The legitimacy of the use of flowering plants (flowers, leaves, oils and resins) is still under discussion. In part it will depend on how hemp will be included in the Official List of Medicinal Plants and internationally by the upcoming UN decision on CBD-based extracts and with THC below 0.2%. However, the fact that a ministerial decree (see previous paragraph) mentioned 'Cannabis sativa inflorescences' among the officinals certainly represents an additional defense weapon for those who today in Italy cultivate, collect and also sell hemp inflorescences (provided that , we always remember, for extraction use and low THC).
According to the main product to be obtained, different cultivation techniques can be chosen with different periods and sowing density (see following paragraphs) and different varieties of hemp, provided they are included in the aforementioned European catalog of varieties of agricultural plant species. The varieties allowed are almost exclusively fiber varieties, however these distinctions can be made:
for the production of fiber, the most suitable are in our opinion the so-called traditional "dioecious" varieties (ie with male and female specimens), as they guarantee an abundant biomass production and have been selected specifically to produce quality fiber: best known dioecious varieties are the Italian Car magnola, CS (Carmagno /, a Selected), Eletta, Fibranova and the Hungarian varieties Kompolti and Tiborszal /, asi;
for the production of food seeds are more suitable
the "monoecious" varieties, ie with organ
the male and female sexuals in the same plant (unisex), as their vegetative development is reduced, the height and the maturation of the more uniform seed are reduced (while in the dioecious the machi mature earlier than the females) and therefore the harvest of the seed is much easier, allowing the use of normal threshing machines. The most common monoecious varieties are the French Futura 75, Felina and Fedora and the Ukrainian Uso-31; dioecious varieties are again privileged for the production of inflorescences. For greenhouse cultivation, a variety from Northern Europe is also interesting, Fi no / a, as it has a very short life cycle and therefore repeatable several times during the year;
For the market of hemp products from seed - food, cosmetics, health - certified organic crops have much more opportunities and indeed for some cosmetics and health care companies, the certified organic product is a prerequisite.
We therefore also advise conventional growers to seriously consider growing hemp as an opportunity to convert to organic.
Hemp is a plant that prefers fresh and deep soils, it does not fear late frosts while it particularly suffers from water stagnation. It is therefore necessary that the hydraulic adjustments are carried out correctly to favor the drainage of excess water. Loose or possibly not too clayey and / or loamy soils are to be preferred since the seedling in the cotyledonary stage is not very vigorous and suffers from the superficial crust. The land on which the hemp is to be sown must therefore be in good conditions, that is, without depressions and / or excessive soiliness, otherwise there is a risk of an uneven emergence that favors the proliferation of weeds.
In the case of organic cultivation, we therefore recommend:
Subsoiling at a depth of about 30 cm, possibly in autumn, to favor the development of the roots in depth. Deep tillage in spring is not recommended as it would leave excessive clods and the soil with a scarce supply of water;
Soil refinement before sowing. For the
control of weeds in organic farming, it is advisable to carry out pre-sowing with a mesh harrow;
False sowing is also recommended as a fight against
SUPPLY OF NUTRIENTS
Hemp is a plant that does not require strong fertilizations, which on the contrary can cause a high vigor with consequent excessive production of leaves and enticement of the crop.
Hemp responds very well to organic fertilizations and biodynamic activators. For a quality production, molasses, algae extracts, mycorrhias can be used to feed soil microorganisms and strengthen the plant's defenses, or organic fertilizers such as manure, poultry or even vegetable compost or digestate can be used up to a maximum of 30 ton / ha, possibly in two phases. In fact, fertilization is advisable to do part in pre-sowing (50%) and part in post-emergency (50%).
The burying of green manure crops (cruciferous or legumes) is a further useful and advisable practice not only for the fertilizing effect, but for the conservation of the organic substance in the soil and for its protective effect against harmful infestations ( pathogenic fungi and nematodes).
It should be borne in mind that the lack of sufficient organic substance is one of the main causes of the production of empty semen.
The sowing of hemp can be done with a normal wheat seeder (or even from corn depending on the spacing you choose), placing the seed at a maximum depth of 2-3 cm. If the soil is too dry, a slight rolling is recommended after sowing in order to favor the conservation of water in the soil.
Optimal sowing period and density vary, as early as possible, according to the main product to be obtained and also according to the choice of variety, given that some varieties are earlier or later than average. Obviously, sowing can be anticipated or even postponed according to the seasonal trend and the amount of water in the soil, but in general:
If the primary goal is to produce fiber, hemp traditionally is sown towards the second half of March. A high sowing density, 50 kg / ha, with spacing at 15 cm is recommended. The high density guarantees rapid soil coverage against insects and better fiber quality, thanks to the development of thin stems;
For the production of seed, the recommended period for the titudini of Central Italy is from the beginning of April to mid-May. Sowing too early (mid-late March) can cause pre-flowering with consequent gradual ripening of the seed which can lead to high losses during the threshing phase. Furthermore, after pre-flowering the plants pos
I'm going back to vegetating. The sowing density can also be reduced to 25 kg / ha and less, without compromising the yield in seed, but in this case with corn spacing (70 cm) in order to allow mechanical weeding between the rows. However, many prefer a higher sowing density (at least 40 kg / ha) for better soil coverage and to obtain a good production of fiber as well;
If the primary focus is on flowering tops, several possibilities open up:
cl. With stable varieties with a low CBD content (1- 2o / o eg Futura 75) we operate as for the seed: sowing in the field at high density (35-40 kg) between April and May. In this case the low CBD content of the individual plants is compensated by the larger biomass production per hectare, by the much lower cultivation costs and by the possibility of a double or even triple harvest (flower + stems or, if the harvest is late , flower + stems + seeds);
With varieties with a good CBD content (4-5% eg Eletta Campana, Ca rmagnola, Tiborszaluzsi) sowing or transplanting in the field between May and June with very low density and wide spacing of 1.5 to 3 meters. In this case it is essential to mulch with biodegradable sheets such as Mater-bi or (possibly two-tone: black below and white above to avoid excessive heating of the sheet in summer) and it is also necessary to prepare an irrigation system with wings under the sheets. dripping. The production costs thus rise significantly (even up to 10,000 euros / ha), but are compensated by the abundant production of quality flowering tops, with bushy plants and with a final yield.
in dried inflorescences on average of 2-5q / ha, but which can also reach 8-1Oq / ha. Until now, as long as one knows how to cultivate according to the GACP (Good Agricultural and Collection Practice), the production costs are amply compensated by the market prices of high CBD inflorescences;
c3. The third possibility is protected cultivation - in greenhouses or indoors - for the production of high quality inflorescences, perhaps in hydroponics or aeroponics. But greenhouse or indoor production techniques are beyond the scope of this manual.
The choices are therefore many, but the most sustainable objective for a grower in our opinion is to choose sowing methods and cultivation practices that allow to obtain at least a double harvest: flower and stems, seeds and stems or flower
+ seeds + stems.
It should also be borne in mind that, unless you choose the production of quality inflorescences (the case c2), a late sowing can cause several problems:
First of all the need for emergency irrigation since the high temperatures of the period could cause the rapid drying of the first centimeters of soil with consequent emergency inhomogeneity;
An excess of weed development following repeated irrigation interventions, since the development of hemp in the first vegetative stages is slow: it takes about 15 days after emergence to cover the inter-row and would therefore be overwhelmed by weeds.
Furthermore, a late sowing could hinder a good development of the root system and the crop would be in conditions of water stress in two fundamental phenological stages, i.e. at the time of the development of the foliar apparatus (essential for intercepting light and therefore producing energy for filling the seed) and at the time of filling the seed.
CONTROL OF WEEDS
The rinettanti abilities of hemp, that is of competition with weeds, have been known practically for a long time. Its rapid development allows it to quickly compete in both light and water with weeds that are generally overwhelmed. But as already mentioned, the preparation of a good weed-free seed bed that allows rapid and homogeneous germination is of fundamental importance.
Hemp irrigation is normally not necessary, especially for fiber production. But in the case of the seed, particularly dry years prevent the filling of the seed, compromising the production. In this case, emergency interventions may be necessary in pre-flowering to develop a good foliar apparatus and in post-flowering to favor filling of the seed, otherwise there is the risk of collecting only empty seed.
Adversities on hemp can be both abiotic and biotic. Those of the abiotic type are the late frosts in the juvenile stages of the plant; strong wind that can lead to the lodging of the crop and hail that can compromise the quality of the fiber and also cause the lodging of the crop. Prolonged periods of drought near flowering and fruit set can lead to a significant drop in yield in seed production.
Biotic adversities are d
different and can cause damage but rarely manage to compromise production. In any case, the Ostrinia nubdalis (Hbn.), Commonly called the corn borer, is perhaps the most frightening insect for hemp as it is also a parasite of corn. The larva generally enters the inside of the stem and digs a tunnel along the stem causing the decapitation of the plant with damage to both the quality of the fiber and the seed production.
Another widespread insect on Tuscan crops is the green mice, Neza ra Viriduf_a, less devastating than the Asian bug.
tica (Halyomorpha halys), but nevertheless capable of causing serious damage especially to the production of seed. It is in fact a phytophagous insect, which feeds on the sap and internal liquids of the plant, thus weakening its seed production. Even a massive presence of Orobanche ramosa (Forsh) can compromise the yield in seed production.
In particularly rainy years in the period of threshing, problems related to the proliferation of Botrytis fungi and Pennicilium on the seeds may emerge.
COLLECTION OF FLOWERING CUMS
Starting in July, the hemp plant gradually slows down its vegetative growth and begins to bloom. In the case of dioecious varieties, the males are the first to flower, while the females flower later, normally from early August. Since it is the female flowers that contain the richest set of cannabinoids and perfumes, it is advisable to wait for the full flowering of the female specimens, when most of the tiny white pistils have darkened, to provide for the harvest. Since once pollinated, the female flowers go to seed, considerably reducing their production of active ingredients, some producers resort, already in the pre-flowering phase, to the so-called 'unmasking', i.e. the periodic manual elimination of the specimens. males from the field. This is a costly operation and definitely superfluous if the product is intended for industrial extraction. To ensure maximum production of CBD and terpenes, various growers resort to purchasing feminized seeds or feminized cuttings. The mechanized harvesting of hemp flowering tops can eg
be done with different systems on the market, which however require
Often modifications are made to adapt the cut to the irregular height of the buds and to ensure easy loading of the cut buds. It is therefore possible to use a cutter bar connected to a loading system (or rather a mower-loader) or a reaper. In any case, cutting systems with variable height are required, capable of rising up to at least 1.5 m from the ground.
Specific systems have recently been created for the collection of inflorescences, such as the German HHHa rvester (https://henryshempharvester.com/), designed for medium-small businesses, which is connected from the front to even a small power tractor with conveying.
SEED COLLECTION - THRESHING
The maturation of the hemp seed is gradual and finding the ideal harvest time is not easy. Generally, the maturation of the seed is carried out until the seeds begin to fall to the ground, ie when the percentage of ripe seeds should be around 60%. Excessive delay
harvesting could lead to a significant drop in yield due to both the drop of the seeds and the presence of birds that are particularly fond of these seeds. It is also advisable to proceed with harvesting when the stem is still green since the dry plants could wind up around the rotary members of the thresher, clogging them and causing the so-called "cordà effect".
Normal threshing machines such as CASE lnternational New Holland, CLASS, Fohn Deere can be used to collect the seed. Machines with axial hammer such as CASE and the new John Deere are preferred. In any case, it is essential to reduce the speed of advancement, of the reel and
of the beaters to avoid tangling of the fibers around the gears and consequent serious mechanical damage. Threshers with straw walkers and without straw choppers are preferable as they risk becoming clogged with fiber.
11199 alkanes for setting 11H non-axial thresher
It is essential that the blades are well sharpened to prevent the fiber present in the stems from going between the blade and the blade beater.
3.17 mm (1/8-inch)
9.5 mm (3/8-inch)
The seed must be left to dry within 4 hours of harvesting, possibly in horizontal dryers and without direct fire on the seed.
JOINT FIBER-SEED OR FIBER-FLOWER COLLECTION
For a double crop of the seed + fiber type, essential for the profitability of the cultivation, normally yes
octave the traditional French system: first you pass with the harvester and then go over with the cutter bar to cut the stems at the base. The double pass, which can also be used for harvesting flower bud + fiber, has the advantage that it does not require special machines, but has two drawbacks: the doubling of costs
harvesting and above all the loss of biomass, due to the crushing of the stems as the combine harvester passes. The solution would be a specialized machine capable of double harvesting in a single pass. Machines of this type already exist in Europe, the best known are the Double Cut Harve sting Machine by the Dutch Hempflax, the Hemp Ha rvester by the Dutch Dun Agro and a machine made by Class specifically for flower harvesting. However, these are machines costing more than € 350,000 and, although fast and performing in cutting, they do not solve the crucial problem generally encountered with modified combines, i.e. the loss of a considerable part (30-40%). of the hemp seed being harvested. In Italy, various projects have been developed in various regions, but have remained in the prototype phase.
POST-HARVEST AGRICULTURAL OPERATIONS: DRYING
Once harvested, both the seeds and the buds, as they are rich in perishable substances and attackable by molds, must be quickly (within 4 hours of harvesting) taken to a dryer that is not over a direct flame. Horizontal tobacco dryers or even better dryers for medicinal plants can be used. Alternatively, if the climate is not humid, the seed can be spread on jute cloths possibly raised from the ground to make aeration and counteract the onset of mold on the seed.
The optimum humidity level to be achieved is 11-12%.
CLEANING OF FLOWERING CUMS
The top, once dried, is still a complex of flowers, leaves, resins, portions of the stem, seeds and weeds. Companies that extract cannabinoids and other active ingredients usually ask to receive a homogeneous chopped product of flowers and leaves, with the minimum presence (generally 2% max.
simo) of foreign material, such as seeds, pieces of stem
The buds must therefore be subjected to a cleaning process, which should consist first of all of an operation of 'sgra naturà (i.e. separation of the stem, lignocellulosic, from the other parts of the bud) and subsequently to a system of sieves to separate the seeds and other impurities from flowers and leaves.
Even the threshed seed, as with any crop, will be full of impurities. It is also easy for a certain percentage of seeds to be empty. Therefore, after drying, it is necessary to carry out a cleaning operation through a system of stone removal and other sieves which allows to separate the seed from both heavy and lighter foreign bodies (including empty seeds).
In various cases it is the same mill to which the seed is conferred to provide for its cleaning.
COLLECTION AND CONDITIONING OF STRAWS
The optimal period for cutting straw for fiber would be at the completion of flowering, 100-11O days from sowing, when the stem has produced the maximum of fiber but is still not very lignified. To have a double product, the best thing is to combine it with the collection of the inflorescences, otherwise the cut must be decidedly postponed to the threshing of the seed.
The hemp stem, as anticipated, can be harvested with various tools: from a simple double-blade bar for the hay gione, possibly flanked by a conveyor to move the stems already in windrows, to a mower conditioner, up to specific machines that cut the stems in two or more portions, Paulitz or Tebeco model. 8
To obtain a quality fiber, for textile use, after the rac
cultured, the straws should be subjected to a controlled maceration process that allows the fibers to be completely separated not only from the hemp, but also from the colloidal substances (pectins) that hold them together. It is the analogous procedure that our grandparents used when they deposited the bundles of hemp in water in the pulp. But it was a long process, which took a lot of work and created nauseating smells. An industrial maceration plant in Italy has not yet been built. And in any case, an adequate system for spraying, combing and spinning the fiber would be required. Consequently, the path of textile fiber is still closed except for small artisan-level productions.
If the most realistic goal is to obtain a fiber for technical use - for example to produce insulating mats, materials
composites or non-woven fabrics - the most convenient method is to leave the cut stems in the field for a few days (how many depends on the climate), in order to reduce the humidity to at least 18%. Once the natural drying has been completed, the grapes are collected in square bales or round bales. The serious problem is the absence in Italy of an adequate network of straw decortication plants, to which the collected material can be transferred. In October 2020, to our knowledge, a single decortication plant has been operating on the national territory, in Ceri gnola in Puglia. The plant is currently able to work annually at the maximum quantity corresponding to 500 hectares of crops. Curated by Beppe Croce - Federcanapa