Cultivation of Poppy in the Temperate Zone

Poppy is cultivated in several countries of the temperate zone. It is cultivated for two purposes: for straw, which is an important pharmaceutical raw; and for seeds and fatty oils which are used in both alimentary and industrial production processes. In certain cases and countries the seeds are marketed as the only product of local poppy cultivation (e.g. in Germany and Austria). However, both the straw and the seed have significant market value and use of them both obviously increases the profitability of the crop.

Poppy plants also have a small but increasing importance as an ornamental species and the dried capsules are used in dried flower compositions. Special cultivars have been developed and produced for this purpose.

Considering the production areas and quantities of harvested poppy straw and seed, the main European countries involved are Hungary, Spain, France, Romania, Slovakia, the Czech Republic and Austria. Although very low production capacity in the 1990s has been recorded in Poland, Bulgaria and Yugoslavia (INCB, 1995), these countries are traditional poppy producers and after the recent economic crisis they may become important players in the market again. Turkey is reported to cultivate several thousand hectares of poppies for purposes other than opium production.

The production of opium has been significant in Turkey, Iran, some parts of the former ex-Soviet Union (e.g. Kirghizia, Kazakhstan, Ukraine) and the former Yugoslavia in the past. However, no licit opium production has been registered in these countries since the 1980s, so opium production in countries of the temperate zone is not considered here.

Cultivation Of Straw And Seed

This work describes cultivation methods for both seed and capsules (straw), combining the main elements of numerous European cultivation practices, but essentially based on Central European methods.

Two main forms of poppy cultivation are found in the temperate zone — the so-called ‘winter’ (autumn-sown seed) and ‘spring’ (spring-sown seed) technologies. Spring poppy cultivation is more widespread in the temperate zone, because overwintering of the plants cannot be ensured in all regions. Apart from low temperatures, winter precipitation may also cause significant damage to autumn-sown crops. However, in some countries autumn sowing is relatively common, especially in Bulgaria, where it is considered the optimal method. Autumn sowing is almost never carried out in northern parts of the temperate zone (e.g. in Poland ()) but can be practised in southern parts of Hungary and Austria with the occasional risk of damage to the crop taken into account.

It is already known that ‘spring’ and ‘winter’ poppy cultivation methods do not differ in agro-technology only. The two types of cultivation are also distinguished by the use of special poppy ecotypes characterized by differing levels of frost resistance.

There are also differences between agro-technologies applied in large-scale production and in smaller private gardens and farms. Figure 1 shows an example of large-scale spring poppy cultivation in Hungary. The biological considerations and some agrotechnological aspects are the same in both cases, but the required seed and straw production can be achieved in different ways depending on the technology and tools available, finance, market aims, etc. In the next sections large-scale technology and some alternatives are presented. An overview of large- and small-scale technologies is given in Table The main elements of highly mechanized and small-scale technologies of ‘spring’ poppy production in Europe:

Time periodMechanised cultivationSmall-scale cultivation
October — Novemberploughingdigging (or ploughing)
Novemberfertilization

smoothing, harrowing

raking
February-Marchsoil sterilizationsoil sterilization
fine smoothing, rolleringfine smoothing
sowing by machine with treated, irradiated or granulated seedssowing by hand, seeds mixed with other small grains
herbicide treatmenthoeing
April-Mayherbicide treatmenthoeing
Mayherbicide treatmenthoeing
May — Junespraying twice minimumspraying 2-3 times
June — Julyspraying in case of epidemic (once or twice)spraying
July — Augustharvesting by combine or special harvester and threshingcutting by hand, separation by hand
cleaning, separation and storagepre-cleaning, cleaning
packing and storage

Land And Climatic Requirements

Poppies can be successfully grown under various ecological conditions. The required temperature is 20-22°C which is ensured in the majority of European areas. Using suitable cultivars, the amount of daylight may not be a limiting factor. However, the amount and distribution of precipitation limits the range of cultivation areas. For the poppy the greatest demand for water occurs at the times of shoot elongation and capsule development and in some cases artificial irrigation becomes necessary. On the other hand, too much rain can be unfavourable during flowering and capsule ripening, decreasing both dry matter yields and alkaloid content In humid regions of the temperate zone damage from plant pathogen fungi can also be a problem. Wind can also cause damage to poppy crops. In the very early developmental stage, soon after germination, the small plants may be driven out while fully developed plants may be broken or blown down before ripening.

The poppy also has special demands on the soil type, preferring a neutral or slightly alkaline pH, and clay — loam soils of high fertility. The most suitable soil types are: chernozem, forest and washland soils of neutral character.

In the temperate zone, poppies can be successfully grown when planted after several other different crops. The most important characteristics of the preceding crop are that it should leave the soil weed-free and with sufficient nutrients. It should be an early harvest crop which provides enough time for soil preparation before sowing the poppy seed. Papilionaceous annual and manured, hoed species are considered to be the best preceding crops. However, under European conditions poppy is most frequently cultivated between two cereal crops.

The new problem of herbicide sensitivity has been described recently (): triasine and carbamide residues and other compounds can accumulate in the soil and harm the crop.

Preparation Of Soil And Fertilization

Because of the more widespread cultivation of spring varieties, the agro-technology used for this type is detailed, while differences concerning the growth of winter poppies are briefly mentioned as they occur.

As poppy seeds are very small, careful soil preparation is required. After harvesting preceding crops, continuous cultivation of the soil is necessary to keep it free of weeds. Deep ploughing — maximum 22-29cm (Morasz, 1979) or minimum 15-18cm — is carried out until the beginning of October, which is followed by smoothing until a properly compacted soil is attained. In this way, by early spring no further deep soil preparation is required and sowing can be carried out at the right time after preparing well pulverized seed beds with a light roller or harrow. This is one of the main prerequisites for optimum plant stand. Although there are references in the literature to the application of spring harrowing it is generally thought that too much soil preparation in the spring is unfavourable.

In small-scale cultivation the same soil conditions are obtained by the using methods and means available locally. In the case of the winter poppy all these operations are again required, but the time period for soil preparation is much shorter because the pulverized seed bed must be ready for sowing at the beginning of the autumn.

Fertilization requirements depend on the soil type, preceding crop, etc. Because of the short vegetation period of poppy, easily absorbed nutrients are used. Farmyard manure is generally avoided because of its favourable effect on weed growth and because it generally lowers the efficacy of herbicides in weed control. Manure is more suitable for use on the preceding crop.

Many factors have to be considered in the application of fertilizers and the optimum dose varies from site to site and is thus characterized over broad intervals. The main macro elements are added in the following dosages, calculated in terms of active agents: nitrogen, 140-160kg/ha; phosphorous 70-110kg/ha; potassium, 80-100kg/ ha. Nitrogen is the most effective nutrient. It has been noted, however, that in certain cases high doses of nitrogen may harm the plant and application rates above 60-80kg/ha are not recommended in these cases. Nevertheless, higher nitrogen rates are required to obtain economical yields under intensive cultivation methods and under irrigated conditions increases in nitrogen may not be effective until 200-240kg/ha doses are applied. The contradictory observations concerning the effectiveness of nitrogen might be a result of differences in both soil type and nitrogen reserves existing in the soil. According to Foldesi (1992), a crop producing 3500kg/ha vegetative mass and 1200kg/ha capsules with seeds had been supplied with 102.5kg/ha nitrogen, 192kg/ha phosphorous and 11.4kg/ ha potassium. Recently, in open field experiments the effect of phosphorous was shown to be very important: its increased supply resulted in higher straw and alkaloid yields (three-to fourfold), while nitrogen and potassium had only a moderate effect (20-40% increases). In some regions granulated superphosphate is applied simultaneously during sowing to accelerate the growth and development of seedlings. The effect of potassium has hardly been studied in open field conditions and, according to Bulgarian practice its application may even be omitted.

Boron should also be mentioned as one of the most important micro elements. Generally, an amount of 25-30 kg/ha ensures the proper development of poppy plants. According to Bulgarian results the application of boron with Zn, Mn and Cu had a more beneficial effect, increasing yields by 28%.

As spring poppy is sown as early as possible, it is recommended that the total fertilizer dose is given during the autumn plough to ensure permeation throughout the soil. However, on very light soils, where water passes through easily, the nitrogen dose may be split and one half or one third of it can be given in the spring.

In the case of the winter poppy, the addition of phosphorous is recommended before sowing at the time of soil preparation, while nitrogen is mostly used as a top-dressing with one third of the dose given in March and two thirds in April.

Sowing

One of the conditions for successful poppy production is an optimal time of sowing. In Hungary sowing should be carried out from February until the end of March, generally depending on the weather and soil conditions. Further to the North, for example in Poland and Germany, sowing is postponed to the second half of March until the middle of April. In southern parts of Europe both autumn and spring sowing is carried out. In general, poppy should be sown as early as possible in the spring, not later than the early grain crops of the given region.

When the surface of the soil is dry and its condition is suitable for preparing a very fine pulverized seed bed, poppy seed can be sown. Spring poppy is not sensitive to moderate frosts.

Winter poppy is sown in the second half of September, so the seedlings should reach a four-six leaf rosette stage before the onset of the low temperatures of winter. If the plants are in an earlier development stage at that time, their chances of overwintering become more uncertain. In Bulgaria the optimal sowing time is considered to be between 20 September and 1 October, immediately before sowing winter cereals. From the data of Popov et al. (1971), this method could produce three to five times higher yields than those of spring-sown seeds in Bulgaria.

In the former Soviet Union sowing was carried out in the autumn with the aim of getting the seeds into the soil but without them germinating before winter frosts. In such cold regions poppy plants are not able to overwinter, but this method of sowing may accelerate development in spring. In this case sowing takes place in the second half of October to the beginning of November.

High-quality propagation material consists of 99% poppy seed with the amount of seeds of other species being less than 100 pieces/kg. The germination capacity then reaches 90% and the water content does not exceed 9%.

The quantities of seed used vary over a rather wide range and depend mainly on the soil preparation and cultivation technology. On average, 300000-400000 individual plants are required per hectare for optimal development and production. As a consequence of naturally occurring limiting factors, this number of plants can be ensured if about twice as many seeds are sown (800000-1 000000). According to the cultivation technology, this plant density can be achieved by using different row and plant spacings. A row separation of 25-40cm has generally been proved to be the optimum. However, on soils infested with a large amount of weeds and where the application of herbicides is limited, an increased row separation of 45 cm — to ensure that mechanical weed control can be undertaken — is generally advised.

There is some contradiction between the optimum number of plants required per unit area and the amount of seed that has to be sown. Because of the small size of poppy seeds, only relatively great doses, 2.0-3.5kg/ha — depending on purity and germination capacity — are able to provide a satisfactory plant stand. The germination power of single seeds is also quite poor so a higher seed density is necessitated. In this way the number of plants becomes much higher than is considered optimal for shoot formation, flowering and capsule formation and as a result of this contradiction thinning has become one of the basic elements of poppy cultivation.

In small-scale cultivation thinning does not usually present an enormous problem. The labour of thinning has been reduced by the use of special sowing methods, i.e. mixing the seeds with small grains of inert material, e.g. semolina, bran, sand. In experiments carried out in the 1950s and 1960s, some seeds were killed by heating and these sterile poppy seeds were used for mixing. However, because the treated grains did not germinate at all, the sprouting of the viable seeds also became uncertain. As a result of the poor germination rates the number of individual plants became much less than the optimum, and the whole stand had to be frequently ploughed off.

For reducing the labour requirements of this procedure and making cultivation more profitable on a large scale, special methods have been developed with the same goals in mind — ensuring good germination without sowing a large quantity of seed which necessitates thinning afterwards.

A method using an irradiated poppy seed mixture was described by Foldesi (1972) and this became one of the most widespread technologies applied in large-scale cultivation. According to this method the propagation material consists of 80% irradiated seeds and 20% non-irradiated (viable) seeds. A well defined radiation dose is used which damages the embryos but does not kill the seeds. The irradiated seeds do not lose their germination capacity totally, rather they are an aid to the germination of the viable seeds and contribute to form a complete stand. The irradiated individuals do not form leaves, they die prematurely and thus thinning is unnecessary. Perfectly homogenous mixing of the irradiated and viable seeds is very important and can be ensured by using standardized seed material for preparation of both components of the mixture. The seeds used for mixing must be from the same cultivar to avoid problems which may arise if some of the irradiated seeds remain viable. The seed rate used with this method is about 3.0kg/ha but on soils which crack easily, a 15-20% increase in this rate is suggested; winter poppy seed should also be sown at a slightly increased dose. In Bulgaria, up to 40-50% more seeds are advised for autumn sowing.

Seed dragees, as used in the propagation of several crops, especially vegetables, can also be used for poppy cultivation. The dragees consist of two or three seeds, because of the weak germination power of single seeds. They can be sown by precision machines at a rate of 7-10kg/ha. About 50-60% of seeds will germinate to give an optimal plant density. Application of this method requires high water saturation in the soil at the time of germination.

In practice, the sowing depth can be between 0.1 and 1.5cm, but with optimal soil conditions a depth of 0.5-1.0cm gives the best results. In very loose soils seeds are sown at a depth of 2-3cm; this is common practice mainly in south eastern parts of Europe.

Rolling is an important operation which can be performed both before and after sowing. In some cases, for instance when the soil is frozen under the surface, rolling seems not to be necessary before sowing. The type of the roller is chosen according to the soil quality.

Characteristic Cultivars

In general, the capsules of the oil poppy have much thinner skins and less developed latex vessels than those of the opium poppy. In each country the main characteristics of the cultivars reflect the ecological conditions and product orientation of the area. The aims of breeding special types are therefore varied: high or very low alkaloid content according to the main product; special alkaloid composition in the case of pharmaceutical applications; high seed and oil yields for alimentary uses; resistance against frosts or pests; winter or spring ecotype characteristics, etc.

The more frequently used cultivars in poppy farming under temperate conditions and some of their main characteristics are as follows.

Kompold M‘. Hungarian cultivar, strong growth, height ll-140cm, 2-3 capsules which are elongated. Vegetation period is 120-130 days. The flowers are white with a violet base. The seeds are light blue. Morphine content: 0.6-0.8%.

Kek Duna‘. Hungarian cultivar, medium height of 110-120 cm. Capsule number reaches 3-4. Vegetation period and flowers are similar to variety described above. Capsules have an elongated pea form and are ribbed. It is also a morphine-producing variety, but its resistance to pests and drought is better. Morphine content: 0.6-0.7%.

Kek Gemona‘. Hungarian cultivar producing narcotine (and morphine), 90-100cm in height, middle-early ripeness. The flowers are white with a violet bottom. The seeds are blue. Morphine and narcotine content: 0.8-1.4%.

Monaco‘. Hungarian codeine (morphine) chemovariety. Vegetation period is 110-120 days. Stem has 2-4 offshoots. The seeds are greyish dark blue. Morphine content: 0.8-0.8%; codeine content 0.5-0.7%.

Novinka 198‘. Ukrainian variety, middle ripening, drought resistant. Morphine content: 0.6-0.8%.

Kozmosz‘. Hungarian winter poppy. Characterized by intensive growth. Its height reaches 130-160cm and has 3-4 capsules. Flowers are light-violet, with a dark spot at the bottom. Capsules are big, ribbed, semi-cone or cone form. Seeds are greenish blue. Morphine content 0.4-0.5%.

Edelweiss‘, ‘Edelrot‘. Austrian varieties, developed from Zwettler Graumohn; differences exist only in the colour of petals (white and red). They are special cultivars for seed; oil content reaches 42.5%. The seeds are big and the capsules have an anthocyanin colouring.

Marianne‘. Dutch variety with white flowers; the capsules (2-3 per plant) are small and closed; seed yield is high.

Dubnik‘. Slovakian hybrid variety (KM 52-2598XMarianne). Vegetation length is 135 days, height 127cm, white flowers, high capsule yield potential (>1.6t/ha).

Gerlach‘. Slovakian hybrid variety (CH-47XMarianne). The flowers are white with a violet bottom. Thousand seed weight reaches 0.6g, yield up to 2.0t/ha. It is relatively resistant to pests.

Albin‘. Slovakian variety, height 130cm, pink flowers, seeds are white and big (thousand seed weight 0.7g), yields are high (1.4t/ha).

Amarin‘. Czech variety, morphine content: 0.69%.

R1‘, ‘R8‘. French varieties, morphine content: 0.68-0.74%.

Extra 2‘. Rumanian variety, morphine content: 0.5%.

Niebieski KM‘, ‘Modry‘. Polish varieties.

Rosemarie‘. Dutch variety.

Flora‘, ‘Soma‘. Swedish varieties.

Reading‘. British variety.

Sanofi‘. French variety.

Mahndorfer‘, ‘Nenga‘, ‘Pilot‘. German varieties.

Parmo‘, ‘Luna‘, ‘Lori‘, ‘Lofti‘. Danish varieties.

Eva Nemeth “Cultivation of Poppy in the Temperate Zone” (1998)