Cultivation of the opium poppy
Cultivation of the oil poppy
Author: G. SHULJGIN
Pages: 1 to 8
Creation Date: 1969/01/01
Most morphine alkaloids are obtained from vegetable raw materials. In the Soviet Union these are raw opium and the crushed capsules of alkaloid varieties of the oil poppy. They are both sources of morphine and their use is strictly confined to medicinal purposes
Morphine requirements are covered by domestic production, which is mainly based on locally-grown vegetable raw materials. Any shortfall of raw material in the form of opium is made up by imports.
Production of the vegetable raw material and of opium alkaloids is a State monopoly, and government authorities strictly control all stages of their production and consumption.
The production and preparation of the vegetable raw material is managed by a special State agency - the All-Union Office for the Production, Preparation and Processing of Medicinal Plants (Lekrasprom), under the Ministry of the Medical Industry.
Lekrasprom supplies chemical and pharmaceutical plants producing morphine with vegetable raw material from its own specialized collective farms and through contracts with other farms.
Biochemical research, seed selection, technological improvement and the mechanization of poppy cultivation are activities of the All-Union Medicinal Plants Research Institute (VILR) and its experimental stations.
The opium poppy is a herbaceous annual belonging to the somniferumspecies of the Papaverfamily.
In Russia the Tungans, a community originating in western China, began cultivating the opium poppy in Kirghizia in the seventies of the last century. Its industrial cultivation, however, developed on a wide scale only in the thirties of this century, to meet increasing requirements of home-produced morphine preparations.
Opium contains twenty-five alkaloids, the chief of which are morphine (C 17H 19O 3N), codeine (C 18H 21O 3N), papaverine (C 20H 21O 4N), narcotine (C 22H 23O 7N) and thebaine (C 19H 21O 3N).
The original of this article is in Russian.
In contemporary medicine, opium alkaloids are used in a wide variety of ways for their analgetic and other properties.
Opium is obtained, in the form of a congealed milky latex, by superficial incision of the poppy capsules during the period of technical ripeness. When biologically ripe, the capsules are cut and the seeds threshed out; these are used mainly in the food industry, whole or as poppy oil obtained by crushing extraction. The seeds contain 46-55 per cent of fat.
In the USSR the opium poppy is sown mainly in the Kirghiz SSR, in the Issyk Kul mountain valley 1,600 m above sea-level. In the centre of the valley is a large lake which does not freeze. In that area the frost-free period lasts 140-150 days. The annual precipitation is 400-500 mm, two-thirds of which falls during the growing season. The average (above zero)temperatures are: April 6-8°C; May 11-12°; June-August 14-18°; September 11-14°. The soils are mainly light-chestnut or chestnut, fine-grained with a humus content of 2.9-4 per cent and a pH of 6.9-7 per cent. To ensure effective control of the production and use of opium, the cultivation of the opium poppy is concentrated in specialized farms and agricultural artels.
Biological characteristics of opium poppy cultivation
The poppy is a self-pollinating plant. Pollination occurs even in the unopened buds; but a small quantity of unpollinated flowers are pollinated by insects during the blossoming period.
The poppy likes long periods of daylight. The longer the days the shorter the growing period, and vice versa. The reverse applies to the formation of morphine. This should be taken into account when siting poppy plantations in different geographical areas and selecting varieties.
The growing season of the poppy comprises the following stages of development:
Growth of seedlings;
Formation of rosette-type leaves and stalks;
Budding;
Flowering;
Technical ripeness (readiness for cutting);
Biological ripeness (ripening of dry seed).
The length of each stage varies considerably from one climatic region to another.
The seeds are very small: their absolute weight is 0.45-0.60 mg (in 1 kg there are 2-3.5 million seeds). They begin to germinate at temperatures of 3-4° above zero. With soil temperatures of 15-18° at a depth of 5 cm, numerous seedlings appear 8-10 days after sowing. These easily survive 4-5° of frost. When sowing in light soils, the covering should not exceed 4-5 cm, and in heavier soils 2-3 cm. Young seedlings grow slowly and are easily choked by weeds. From the time of the appearance of the seedlings to the budding period, the poppy requires moderate temperatures and adequate soil moisture (70-80 per cent of saturation). Hot dry weather between the end of flowering and the period of technical ripeness causes the formation of large quantities of opium and the accumulation of formin.
Technical ripeness sets in 14-16 days or, with lateripening varieties, 18-20 days after mass flowering.
During its seedling period the poppy requires large quantities of phosphorus fertilizer. During budding and flowering it requires increased quantities of all the other basic elements (N, P, K), especially nitrogen. In experiments carried out in conditions typical of Kirghizia, the application of these types of fertilizer during the principal stages of development gave the following figures (in kg per ha);
|
Stage |
N |
P 2O 5 |
K 2O |
|---|---|---|---|
|
Rosetting
|
1.26 | 0.26 | 1.20 |
|
Budding
|
55.2 | 18.6 | 76.4 |
|
Technical ripeness
|
61.4 | 28.3 | 74.2 |
Varieties and seed-growing
For opium poppy cultivation, selected varieties are used which have been developed at the experimental stations of the All-Union Medicinal Plant Research Institute (VILR). These varieties are essentially derived from the Tarbagotaisky and Tyanshansky subspecies. At present, a considerable part of the poppy-growing area is sown with the most promising varieties having different ripening periods:
"Przewalski-222" (early-ripening),
"Przewalski-D250" (middle-ripening), and
"Przewalski-133" (late-ripening).
Each year the VILR experimental stations grow selected seed of these varieties and propagate it on special seed-growing farms; they gather the primary seed in the quantities required for the whole area to be sown with poppies. In this way the poppy-growing farms obtain for sowing each year selected primary seed with high germination properties.
Techniques of opium cultivation used in the USSR
The poppy is usually placed in the crop rotation after winter cereals, and also after grass or occupied fallowing.
The ground is prepared in autumn (autumn ploughing). Ploughing is 25-27 cm deep. During autumn ploughing the basic fertilizers (N, P, K) are applied. In early spring the ploughed land is harrowed and, before sowing, is cultivated all over (to a depth of 4-5 cm) with a drag harrow.
Sowing is done as early as possible and not later than the sowing of early grain crops. The standard sowing density per hectare is 2-3 kg of seed with 90-95 per cent germination. The seed is covered to a depth of 2-3 cm. It is mixed with granulated superphosphate, which acts as a filler and provides accessible phosphorus nutrient in the soil for the young seedlings. Experience has shown that the addition of superphosphate when sowing increases the crop of opium and seed by 15-20 %.
Before sowing, the seed is dusted with granozan or mercuran (1g to 1 kg of seed), which protects it and the seedlings from damage by pests and diseases.
The seed is sown in continuous rows 60 cm apart, by vegetable drills or by grain drills with roller-seeders for sowing small seeds. The 60 cm inter-row spacing enables the field to be furrow-irrigated.
After sowing, the next operations are thinning the seedlings, weeding and hoeing, and watering when soil moisture is insufficient.
When the seedlings appear, they are first thinned when they show two pairs of true leaves. The second thinning takes place when 5-6 pairs of true leaves appear. After the second and final thinning, the density of the plants should be 120,000-140,000 per hectare. Experiments have shown that 70,000-80,000 plants per hectare give 26.9 kg of opium; 100,000-110,000 give 31.04 kg; and 121,000-130,000 give 35.16 kg; the corresponding figures for morphine are 3.66 kg, 4 kg and 5.17 kg per hectare.
The inter-row spaces are weeded and hoed with tractor-drawn furrow-cultivators.
Most of the poppies in the Issyk-Kul valley area are grown on irrigated land. When the moisture content of the soil is insufficient - i.e. when it falls below 70 % - deep irrigation is given, particularly when the seedlings are sprouting and growing and in the rosette and budding stages, to obtain rapid and regular growth; and the plants are watered for growth during the subsequent development stages. Furrow irrigation is used, and the average quantity of water is 800 m 3 per hectare.
Manuring of poppy plantations
During the autumn sowing the following quantities per hectare of mineral fertilizers are applied:
|
Superphosphates
|
300-400
|
|
Nitrogen
|
150-200
|
|
Potash
|
100-150
|
When organic fertilizer (manure) in quantities of 10-15 per hectare is used, the quantities of mineral fertilizer applied are reduced by 30-35 %.
Good results are obtained when manure is spread during the autumn ploughing in quantities of 15 t per ha, and superphosphates and nitrogen fertilizers are applied as a twofold top-dressing during the rosetting and budding stage.
The effects of organic fertilizers (manure) and superphosphates, applied during autumn ploughing, on the yield of opium and seed are shown by the following test data:
|
Yield per hectare as percentage of control sample |
||
|---|---|---|
|
Experimental variant
|
Dried opium
|
Seed
|
|
1. Without fertilizer (control)
|
100 | 100 |
|
2. Phosphorus - 90 kg/ha
|
181 | 209 |
|
3. Phosphorus - 90 kg/ha plus 15 t manure
|
193 | 213 |
|
4. Phosphorus - 90 kg/ha plus 30 t manure
|
198 | 214 |
Apart from the main manuring, the yield of opium and seed is further increased by up to 30 % over the yields obtained in the four experimental variants of the main manuring, by applications of granulated superphosphate during sowing and by nitrogen top-dressings during the growing season.
The granulated superphosphate is added to the seed during sowing in quantities of 30 kg per hectare. Top-dressing with nitrogen fertilizers is done with mechanical cultivator plant-feeders during the rosetting stage and again during the budding stage, in quantities of 45 kg nitrogen per ha in each stage. Nitrogen top-dressings are particularly effective before irrigation.
Opium poppy pests and diseases, and measures against them
The most dangerous pests are the seed and capsule weevils (the harm is done during the larvae stage). The main soil-dwelling pests are click beetles, turnipmoth and other caterpillars. Bean and poppy aphis also do damage. Amongst fungus diseases of poppies, peronosporium and helminthosporium have been observed, and amongst bacterial diseases trachsobacteria (blight).
Systems of agrotechnical and chemical measures have been worked out and used against poppy pests and diseases.
Harvesting and processing of raw opium and seed
The gathering of opium begins during the technical ripeness period of the capsules, which sets in 16-18 days after mass flowering (July-August). Technically-ripe capsules are elastic to the touch and have a light grey-blue waxy coating. During this period the seed is in the stage of milky ripeness.
Incisions are made first in the capsules on the main stem and later in those on lateral stems. In the USSR - unlike India - the capsules are incised horizontally, ensuring abundant exudation of milky latex.
On an average three incisions are made in every technically-ripe capsule at intervals of one or two days. Capsules are incised by day, from 12 - 1 till 5 - 6 p.m., and the milky latex which drips out of them, already in the form of congealed opium, is removed from them with scrapers on the morning of the following day from 5 to 10 a.m. Two days' delay in starting to incise technically-ripe capsules results in a loss of 7 %, and six days' delay of 30 %, of the latex.
In cloudy, rainy weather the capsules are incised and the opium is collected on the same day, with an interval of 4-5 hours.
The first incision is made towards the top of the capsules on the south side; the second (somewhat lower) on the north side; and the third (still lower) again on the south side.
The capsules are incised with a special three-bladed knife with limited depth of cut (figure 1). The distance between the blades of the knife should not exceed 3-4 mm. Experiments have shown that a large number of blades on the knife does not increase the exudation of milky latex or the amount of opium collected.
FIGURE 1
Position of hands Position of incisions for incising capsule on capsule
The opium is removed from the capsules with a scraper (figure 2) and placed in a jar. The outfit for incising capsules and collecting opium is shown in figure 3.
When removing the raw opium from the capsules, the collectors take care not to scrape epidermis off them as well, since that would lower the opium's commercial quality.
FIGURE 2
Removal of opium
FIGURE 3
Outfit for incising capsules and removing raw opium : (1) knife; (2) blades and inserts; (3) jar; (4) scraper.
The incising and opium-collecting period lasts 25 days in the Issyk-Kul Valley, and on a single farm 15-20 days. The cultivation on each farm of three types of poppy which take different times to reach technical ripeness lengthens the lancing and harvesting period by 5-10 days. This enables a smaller number of workers to gather the whole yield of raw opium in good time and without loss.
Experience has shown that with three incisions practically the whole possible yield of opium is collected, and that to expend much labour on a fourth incision, let alone a fifth, is uneconomic.
Organization of collection and reception of raw opium
Strict control is applied during the opium harvest in poppy-growing areas and farms to ensure that the whole opium crop is maintained intact and delivered to the State processing plant.
Before the harvest each collector is assigned an area of 0.15-0.20 hectares from which he must ensure, in accordance with the rules of the harvest, that all the opium is collected.
Each collective or State farm worker is given a smock and an outfit (knife, scraper, jar, etc.). All the opium he collects he hands over to his brigadier actually on the field, for weighing. It is placed in aluminium containers (capacity 40 kg), and on the same day is sent under guard from the fields to the State processing plant.
When the opium received separately from each brigade and farm arrives at the plant, it is mixed together (in a dough-mixing machine) into a homogeneous mass and again placed into aluminium cans and weighed. Three average samples are prepared from small quantities taken from each can and are sent to the laboratory for analysis of the morphine content of the opium.
The analysis results are used as the basis for payment to farms for the opium obtained from them not by its physical weight but per kg of its morphine content. Differential prices for 1 kg of morphine content are fixed for different areas, depending on the conditions of production.
According to the standards (GOST 4813-51) laid down in the USSR, raw opium must meet the following requirements:
Appearance: a doughy, homogeneous mass, light or dark grey, without foreign admixture (fragments of capsule or other plant matter). Its humidity content should not ordinarily exceed 45 %. The morphine content of absolutely dry opium should be not less than 10 % and the codeine content not less than 1 %.
The official standards also specify methods for determining the commercial quality and chemical composition of opium.
To prevent fermentation of opium during transport and storage, 1 % by weight of sodium metabisulphite is added as a preservative when the separate batches of opium received from the farms are mixed in the dough mixer.
Depending on the weather conditions, the level of farming techniques and other external factors, the yield of opium from 1 hectare varies substantially from one year to another and, in a single year, from one farm to another. The average opium crop, with 45 % humidity, is 30-35 kg/ha, with a morphine content of 7-8 %.
Individual farms which use the full range of modern farming techniques and the new varieties of seed obtain opium yields of 50-60 kg/ha, and in exceptionally favourable years up to 80 kg/ha. The yield of seed, per hectare does not on an average exceed 250 kg, although the biological crop of seed is considerably higher. The farms harvest the capsules late and part of the seed is lost by dispersion.
A major problem in opium poppy cultivation is the high expenditure of labour. Depending on the size of the crop and the level of mechanization, between 1,300 and 1,500 man hours - two-thirds of which are spent on the incision (triple) and collection of opium by hand - are required per hectare of poppies.
Experiments have shown that a more economic method of obtaining opium is to carry out only one incision and collection, after which all the capsules are harvested and threshed on attaining biological ripeness and, after the seed has been separated, sent to a plant for extraction of the morphine remaining in them. The efficiency of this method is confirmed by the experiments and calculated results of the VILR.
|
Collection of morphine in kg/ha |
Expenditure of labour in man hours |
||||
|---|---|---|---|---|---|
|
Variety of opium poppy |
By the usual multi-incision method |
With a single incision |
Yield of morphine with single incision as percentage of yield with multi-incisions |
With a single incision |
With multi-incision |
|
Early ripening 222
|
3.28 | 2.7 | 82 |
-
|
-
|
|
Middle ripening D250
|
4.26 | 3.34 | 78 |
-
|
-
|
|
Late ripening 133
|
4.57 | 3.48 | 76 |
-
|
-
|
|
Average
|
4.36 | 3.17 | 72.7 | 284 | 880 |
The single incision and collection of opium thus gave on an average 72.7 % of the quantity of morphine obtained per hectare with several incisions for less than one-third of the expenditure of labour.
According to the results of a test with the middle-ripening variety, D250, after a single incision an additional quantity of morphine amounting to 1.34 kg/ha can be extracted from the capsules.
Middle-ripening D250 (ripening 16 days after mass flowering)
|
Weight of capsules harvested
|
590 kg/ha
|
|
Weight of remaining morphine as percentage of weight of capsules
|
0.45 %
|
|
Quantity of morphine in capsules
|
2.68 kg/ha
|
|
Industrial extraction of 50% of morphine content
|
1.34 kg/ha
|
It is clear from this example that, if the capsules are incised once and the opium is collected, and if then they are harvested and the morphine is removed from them by extraction, one hectare of middle-ripening D250 opium poppy will yield the following quantities of commercial morphine:
|
(
a) From raw opium (3,34 kg/ha, of which the industrial process extracts 85 % = 2.7 kg/ha)
|
2.7 kg/ha
|
|
(
b) From capsules incised once
|
1.34 kg/ha
|
|
Total
|
4.04 kg/ha
|
or as much as is obtained with multi-incisions, but with an expenditure of two-fifths to one-third of the labour.
By production practice poppy-growing farms can sell capsules at fixed prices after the first or even after a second incision if their remaining morphine content is not less than 0.25 %.
With a view to lowering the labour cost of harvesting capsules and collecting opium, the Design Office in Kirghizia is working on the construction of a special machine by which this labour-intensive process can be mechanized.
The oil poppy also belongs to the somniferum variety of the Papaver family. The sub-species most widespread in the USSR is the Eurasian.
The commercial part of the oil poppy is the capsule with up to 30 cm of the stalk (straw) and the seed.
Morphine is obtained by crushing the straw, and the seed is used for food.
The oil poppy is mainly sown in the Ukraine, in parts of the central black-soil area, and in the Central Volga Basin on non-irrigated land.
The capsules of the oil poppy have much thinner skins and less developed latex vessels than those of the opium poppy. The morphine from its capsules (straw) is obtained by extraction in special plants.
The morphine content of the straw varies widely, from 0.3 to 0.8 %, according to the quality of the straw, the area where it was grown and the weather conditions there.
The growing season is 95-115 days. Seedlings appear 6-8 days after sowing. The length of the rosette stage is 43-50 days. Then comes the phase of stalk growth, which lasts 12-14 days. Budding lasts 10-12 days and flowering 10-14 days.
The seeds are fully ripe (biological ripeness) 20-25 days after mass flowering.
At the various stages of its development, the oil poppy requires different external conditions. Its seedlings, like those of the opium poppy, easily survive 3-4°of frost. During the period of seedling growth and until the flowering stage, it requires sufficient soil moisture (65-70% of saturation). During the seedling stage it requires increased phosphorus nourishment applied near the roots; during its subsequent stages of development up to mass flowering its need of nitrogen increases.
At the end of flowering up to full ripeness of the seed, low temperatures and excessive soil moisture hinder accumulation of morphine, and precipitation in the harvest period causes loss of morphine
Varieties and seed growing
Poppy farms are recommended to plant the "Novinka 198" alkaloid variety of oil poppy, bred by the Lubenka experimental station of the VILR (Ukrainian SSR). It is high-yielding, middle-ripening and drought-resistant. The morphine content of the capsule is 0.6-0.8 % and the yield of seed 1,000-1,2000 kg/ha. The average ratio by weight of the capsules to the seeds is 1: 1.2-1.5.
Methods used by oil-poppy farms
Highest yields of capsules and seeds are obtained on fertile soils with good physical properties: sandy or loamy black soils, dark or light-chestnut soils. The poppies do not like saline soils heavily encumbered with weed roots.
The poppy is placed in the crop rotation after fertilized clean fallow, winter cereals and occupied fallow. The sowing of two poppy crops in succession is not recommended.
For preparing the soil, the autumn ploughing system with cultivation before sowing is adopted. In the winter, snow retention is practised on plots earmarked for poppy cultivation in order to preserve the moisture in the soil.
Seed giving 85-95 % germination is sown as early as possible in the spring, in rows with 45 cm spacing. The standard for sowing is 2-3 kg of seed per hectare, with 2-3 cm covering. During sowing, 40-50 kg of granulated superphosphate mixed with 2-3 kg of hexachlorane are added to the soil to kill the larvae of the poppy weevils which attack the seedlings.
Before and after sowing, the field is rolled with flat or ring rollers.
If, after sowing, a soil crust forms which prevents the seedlings from sprouting, it should be broken with a light harrow drawn across the rows.
When two to three pairs of true leaves appear, the seedlings are thinned with a 2 PSN- 6M beet thinner or, if their density per linear metre is less than 40-50, with a light harrow. If their density is less than this, they are best thinned by hand.
The normal stand for oil poppies after thinning is reckoned to be 18-20 plants per linear metre or 400-450 thousand plants per hectare; in dry areas 16-17 plants per metre or 350-380 thousand per hectare.
The manuring system consists in the application of the basic fertilizers during autumn ploughing (300-400 kg of superphosphates, 200 kg of ammonium nitrate, 75-100 kg of potassium salts per ha); the application of 40-50 kg of granulated superphosphates before sowing; and one or two nitrogen top dressings (100 kg of ammonium nitrate per ha) during the rosetting stage and at the start of budding.
The most harmful poppy pest is the root weevil. When, in spring, large infestations of weevils are observed in the fields, a 12 % hexachlorane or DDT powder is applied (20 kg per ha). If necessary, the application is repeated during the leaf-formation stage.
To destroy capsule weevils during the budding stage, the plantation is dusted with a mixture of 12 % hexaclorane and 5.5 % DDT (25 kg per ha).
The poppies are harvested when the capsule is yellowish-grey and the seeds can be heard rustling when it is shaken. Harvesting is done with specially-adapted grain combines. Individual farms gather the capsules by hand, reaping them with sickles and breaking them up on the threshing floor. Combines cut the plants at a level at which the stems with the capsules are not longer than 30 to 35 cm.
When the capsules (straw) are threshed by combine they are passed, together with the seed, out of the combine hopper into the mechanism and discharged on to the threshing floor. There the raw material is dried, the seed is separated from the chopped-up capsules and stems with a grain-husking machine and delivered separately to the processing plant.
During the last two years the quality of the straw has substantially improved. Whereas previously the collective farms delivered straw containing large quantities of stalk, the straw now delivered mainly consists of capsules and its morphine content has considerably increased. Farms receive a cash bonus for increasing the capsule content of the straw.
Under existing technical conditions in the USSR the capsules (straw) should fulfil the following conditions: different degrees of division of capsules and stalks; colour - brownish-yellow to grey; moisture not more than 14%; organic admixtures (other plants) not more than 2 %; mineral admixtures not more than 2 %; proportion by weight of capsules in the raw material not less than 60 %; proportion of stalks and leaves not more than 36 %; morphine content of the capsules (straw) not less than 0.25 %. figure4.1figure4.2
Mobile Twin-Plunger Press (side view)
The Plunger Press seen from above (The parts of the machine; indicated by numbers on the diagram, are not discussedn in this paper.)
The actual quality of the commercial raw material (straw) delivered by farms and the yield of capsules (straw) vary considerably from one farm and from one year to another.
The average yield of marketable capsules (straw) on State farms owned by Lekrasprom in 1967 was: capsules (straw), 369 kg; seed, about 400 kg (the figures were lower on collective farms).
Individual farms (State or collective) using highly-developed methods produced 500-600 kg of capsules and 600-700 kg of seed.
Owing to the improvement in the quality of the straw, the average morphine content throughout the USSR in 1967-1968 rose to 0.46 %, varying in different regions from 0.36 to 0.68 %. In dry years - particularly during the ripening period - the morphine content is usually higher.
Owing to the low bulk weight of the capsules (straw), considerable space is required for their storage and the cost of their transport to the factory by rail is high.
To reduce storage and transport costs, the capsules (straw) are pressed into briquettes with a specially-designed mobile twin-plunger press (figure 4) powered by a 75 hp motor, and having an output of 1.5-2 t of briquettes per hour. The briquettes are cylindrical (diameter 110 mm, length 20-30 mm) and their density is 0.4-0.6 t/m3. In the steam chamber (before extraction) they disintegrate in 2-2.5 minutes. Their storage and transfer requires only two-fifths to one-third of the former warehouse and wagon space, so that the money cost of these operations is substantially reduced.
The cultivation of oil poppies and production of capsules (straw) and seed on large farms is fully mechanized. Suitable techniques and sets of machines have been designed for poppy farms, so that the labour expended per hectare does not exceed 160-200 man-hours.
The cultivation of the oil poppy in the USSR, with dual use of the capsule (straw) for obtaining morphine and the seed for food, is economically profitable for the State and for poppy farms.
Morphine obtained from the capsule (straw) of the opium poppy by industrial extraction costs, at current buying and selling prices only one-half that obtained from opium, and its production is free from the dangerous social phenomena (diversion, smuggling, drug addiction) which may accompany opium poppy cultivation and the production of opium on plantations where large numbers of workers are employed.
The VILR experimental stations and laboratories are continuing their work on increasing the productivity of oil poppy cultivation.
Research has proved the efficiency of sowing poppies in rows 35 instead of 45 cm apart. This gives a 40 % higher yield of capsules and seed because of the larger number of plants per hectare and the more even spreading of fertilizer over the area.
Sowing of rows 35 cm apart with machines adapted to the narrower spacing is recommended for weedless ground.
The results of plant-growing experiments carried out in 1965 and 1966 at the VILR agro-chemical laboratory confirmed the favourable effects of micronutrients on poppy yields and especially on the production of seed.
|
Additional yield as percentage of control sample |
||
|---|---|---|
|
Micronutrients |
Seed |
Capsules |
|
Manganese, 1 mg per kg of soil
|
up to 44
|
11-22
|
|
Molybdenum, 2-3 mg per kg of soil
|
up to 58
|
25 |
|
Boron, 1 mg per kg of soil
|
up to 63
|
17-20
|
No special changes produced by micronutrients in the morphine content of the capsules have been observed. Field experiments with micronutrients will be conducted.
The Siberian experimental station of the VILR is experimenting with the application of defoliants to speed up the ripening and drying of capsules on the standing plant. This has considerable importance for northern poppy-growing areas, where the harvest often coincides with cold and rainy weather.
The experiments have shown that the best results are obtained when the poppies are sprayed with magnesium chlorate in doses of 20 kg/ha on the 35th day after the beginning of mass flowering.
Drying the poppies enables harvesting to be started 5-7 days earlier. The moisture content of the capsules at harvest is 15 % lower than in the control samples. The Lubenka and Przewalski experimental stations of the VILR are working on the selection of oil poppies to develop a variety with a higher formin content in the capsules.
We believe that, as the productivity of the oil poppy increases, as wider areas are sown with it, and as total harvests of poppy straw - which has proved its value as a raw material - increase, the production of raw opium in the USSR will gradually be reduced and in due course will entirely disappear.
