Tomáš Lošák, Rostislav Richter
Mendel University of Agriculture and Forestry Brno, Czech Republic Faculty of Agronomy, Department of Agrochemistry and Plant Nutrition
Split application of nitrogen in the poppy
(Papaver somniferum L.) nutrition
Zastosowanie dawek dzielonych azotu w nawożeniu maku
(Papaver somniferum L.)
Key words: split application, nitrogen, poppy, yield, seed, morphineEfficiency of partial doses of nitrogen in different growth stages applied to poppy (Papaver
somniferum L.) plants, cv. Opál, was investigated in a pot experiment. Nitrogen was applied either in
a single dose at the beginning of a growing season in doses of 0.6 and 0.9 g N per pot or in two split doses in the total amount of 0.9 g N per pot as ammonium nitrate. In these variants, the dose of 0.3 g N (1/3 of whole dose) was applied either at the stage of leaf rosette (DC 35) or stem elongation growth (DC 41) or flowering (DC 49).
After harvest, the following parameters were evaluated: number of poppy capsules per plant and their volume, yield of seeds and percent of morphine in capsules produced for pharmaceutical industry (i. e. in empty capsules with 15 cm of stems). With increase of nitrogen fertilization from 0.6 to 0.9 g N per pot applied at the beginning of growing season poppy yield increased not significantly. The split application of the higher dose (0.9 g N per pot) in comparison with one application profitably influenced yield. The highest yield was achieved when the dose of 0.3 g N per pot was applied at the flowering time.
The volume of poppy capsules was dependent on nitrogen dose and the time of application. The highest value of this feature was noticed when the whole dose of 0.9 g N per pot was applied at the beginning of growing season. The increase of nitrogen fertilization from 0.6 to 0.9 g N per pot applied at the beginning of growing season increased significantly the number of capsules. Partitioned application of a higher dose (0.9 g N per pot) decreased the number of capsules per pot. With the increase of nitrogen fertilization the morphine content in capsules increased.
Słowa kluczowe: dzielona aplikacja, azot, mak, plon, nasienie, morfina
Doświadczenie wazonowe zostało przeprowadzone w celu oceny efektywności nawożenia azotem zastosowanego w różnych terminach agrotechnicznych uprawy maku odmiany Opal. Mak nawieziono azotem jednorazowo na początkuwegetacji dawką0,6 i 0,9 g N na wazon lub dwukrotnie, gdy 0,6 g N na wazon zastosowano na początku wegetacji, a 0,3 g N na wazon — w stadium rozety (DC 35) lub wzrostu elongacyjnego łodygi (DC 41), albo w fazie kwitnienia (DC 49).
Po zbiorze oceniono: plon nasion, liczbę i wielkość makówek oraz zawartość morfiny w mako-winach (puste makówki z 15 cm łodyżką). Ze wzrostem nawożenia z 0,6 do 0,9 g azotu na wazon, zastosowanego na początku wegetacji, plon nasion wzrósł nieistotnie. Zastosowanie wyższej dawki nawożenia (0,9 g N na wazon) w dwóch terminach, w porównaniu z nawożeniem jednorazowym, korzystnie wpłynęło na wysokość plonu. Najwyższy plon uzyskano, gdy 0,3 g N na wazon zastoso-wano w okresie kwitnienia.
Wielkość makówek była zależna od dawki i terminu nawożenia azotem. Najwyższe wartości tej cechy odnotowano, gdy całą dawkę 0,9 g N na wazon zastosowano na początku wegetacji. Wzrost nawożenia azotowego z 0,6 do 0,9 g N na wazon, zastosowanego na początku wegetacji, zwiększył istotnie liczbę makówek. Nawożenie maku dawką 0,9 g N na wazon podzieloną na dwie części i stosowaną w dwóch terminach przyczyniło się do zmniejszenia liczby makówek. Wraz ze wzrostem nawożenia azotem zwiększyła się zawartość morfiny w makowinach.
Wyniki doświadczenia wazonowego wskazują, że zastosowanie azotu w dwóch dawkach korzystnie wpłynęło na odżywienie maku (Papaver somniferum L.). W porównaniu z nawożeniem jednorazowym zastosowanie tej samej dawki azotu w dwóch dawkach umożliwiło uzyskanie wyż-szego plonu (o 7,23–44,42%). Najwyższy plon osiągnięto, gdy 1/3 całkowitej dawki azotu zastoso-wano w okresie kwitnienia. Nawożenie maku dawką 0,9 g N na wazon w dwóch terminach przyczy-niło się do zmniejszenia liczby makówek. Wielkość makówek i zawartość morfiny w makowinach zwiększyła się wraz ze wzrostem nawożenia azotem.
Introduction
In recent years, the interest in cultivation of poppy (Papaver somniferum L.) has rapidly increased among Czech farmers and for the time being its total acreage is approximately 38,000 hectares with an average yield of 0.6 t ha-1. In Europe, the
Czech Republic is the most important producer and exporter of poppy (Vašák et al. 2003) and it seems that not only poppy seed is a lucrative commodity but also morphine contained in poppy capsules because it can be used in pharmaceutical industry.
To reach required yields and high quality of products it is necessary to assure an optimum nutritional status of plants during the whole growing time. Poppy has a relatively short growing time and a shallow root system. Its successful growing is based on a well-balanced supply of all macro- and microelements into the soil, which is reflected both in high yield and top quality of produced seeds (Costes et al. 1976, Ramanathan 1979). When growing poppy, the supply of nitrogen and especially its optimum doses and time of application play a very important role (Yadav et al. 1984). According to Pavlíková et al. (1994), it is also important to use a suitable source of nitrogen, especially as far as its uptake by plants and the seed yield are concerned. As mentioned by Jain (1990), Kharwara et al. (1988) and some other authors, partial doses of nitrogen are justified above all with regard to seed yield and content of alkaloids.
Material and Methods
A pot experiment was established on 27 March 2003. The medium heavy soil was characterised as fluvisoil and its agrochemical characteristics were as follows: the soil pH was neutral, contents of P and Ca were high, content of K satisfactory and content of Mg good. Plastic pots were filled up with 9.5 kg of soil each.
Table 1 Agrochemical characteristics of soil — Agrochemiczna charakterystyka gleby (Mehlich III)
Content of available nutrients [mg kg-1]
Zawartość dostępnych składników odżywczych
Total S (mg kg-1) Siarka ogółem pH/KCl P K Ca Mg Sws. S-SO4 2-6.75 120 166 3377 224 9.1 6.0 Sws.= Swatersoluble
Seeds germinated at relatively low temperatures (0–6oC) at the beginning
of April. Variants of nitrogen doses, supplied in the form of ammonium nitrate are presented in Table 2.
In growth stage DC 22 (2 pairs of leaves) on 5 May 2003, in Variants: 2, 4, 5, 6 the dose of 0.6 g N per pot was applied. In this growth stage in Variant 3 the dose of nitrogen amounted to 0.9 g per pot. In Variant 4, a supplementary dose of 0.3 g N per pot in the form of ammonium nitrate was applied in the growth stage DC 35 (leaf rosette) on 19 May 2003; in Variants 5 and 6, the corresponding doses of N were applied in growth stages DC 41 (stem elongation growth) and DC 49 (flowering) on 30 May and 13 June 2003, respectively (Tab. 2).
Table 2 Experimental scheme — Schemat eksperymentu
N-dose [g pot-1] — Dawka azotu [g wazon-1] Variant
Wariant 2 pairs of leaves DC 22 2 pary liści
DC 35 leaf rosette
liść rozety
DC 41 stem elongation growth
stożek wzrostu DC 49 flowering kwitnienie total razem 1 – – – – – 2 0.6 – – – 0.6 3 0.9 – – – 0.9 4 0.6 0.3 – – 0.9 5 0.6 – 0.3 – 0.9 6 0.6 – – 0.3 0.9
During the experiment, plants were regularly irrigated with demineralised water and treated with Karate 2.5 EC against aphids. Samples for chemical analyses were taken off in stages DC 35, DC 41 and DC 49.
Plants were harvested in full ripeness (4 replications) on 22 July 2003. Yield of poppy seeds per pot (4 plants), volume of capsules, number of capsules per pot and content of morphine in empty capsules were evaluated. The content of this alkaloid was determined polarographically in the Research Institute of Oilplants Opava. Seed yields were evaluated using statistical methods with the expression of minimum significant differences.
Results and Discussion
Yield of poppy was influenced by nitrogen fertilization (Tab. 3). As compared with control — Variant 1 (100%), increase of yield ranged from 173.76% to 221.69%. No statistical differences were found between N1 and N2 nitrogen doses
(Variants 2 and 3, resp.).
Table 3 Average yield results — Przeciętne wyniki wydajności
Seed yield Plon nasion Variant Wariant Experimental scheme Schemat
doświadczenia [g/wazon] [g/pot] [%]
Volume of poppy heads [ml/plant] [ml/roślinę] Number of capsules per pot Morphine content Zawartość morfiny [%] 1 Controls 4.84 100.00 6.3 3.5 0.78 2 N1PK 8.41 173.76 9.1 4.0 0.85 3 N2PK 8.58 177.27 13.1 6.75 0.96 4 N1PK + N v DC 35 9.00 185.95 10.6 5.0 0.97 5 N1PK + N v DC 41 8.93 184.50 10.9 4.75 1.01 6 N1PK + N v DC 49 10.73 221.69 12.5 4.0 0.91 Dt 0,05 0.86 1.4 0.47 Dt 0,01 1.17 1.9 0.63
The increase of yield influenced by split application of nitrogen amounted to 8.68, 7.23 and 44.42 percentage point in Variants: 4, 5 and 6, respectively. This result corresponded with data published by Solanki et al. (1998) who demonstrated that the partitioned doses of nitrogen showed a positive effect on yields of poppy seed. As mentioned by Jain (1990), three partitioned doses of N, i.e. at sowing (1/4), in the growth stage of leaf rosette (1/2) and before flowering (1/4) resulted in the highest yields of seeds. Gupta et al. (1984), also, obtained the highest yields when nitrogen was applied in three partitioned doses.
Application of 1/3 of the total N dose in the growth stage of flowering (DC 49) led to the highest yields. The difference between Variant 6 and Variants: 3, 4, 5 was highly significant (P0.01). This observation corresponded with the results
published by Laughlin et al. (1992) who applied a part of N dose before flowering. Increase of yield is dependent on soil humidity and in optimal conditions yield can increase from 20 to 40%. The volume of poppy head was also dependent on
nitrogen supply and the highest values were recoded in Variant 3 (N2PK). Our
results corresponded with data published by Jain et al. (1990) who mentioned that an increase of the dose from 30 to 90 kg N ha-1 caused an increase of the capsule
volume by 58%. Solanki et al. (1998) demonstrated that the application of partitioned N doses on three different dates showed a positive effect on the total
volume of poppy heads. Differences between unfertilised control (Variant 1) on the one hand and all fertilised variants (2–6) on the other were statistically highly significant. Statistically significant differences (P0.05) in the total volume of capsules
were found also between Variants 4, 5 and 6, which received supplementary doses of N in the course of growing season (viz. 10.6; 10.9 and 12.5 ml plant-1, resp.). This means that it is not possible to conclude that the highest yield of poppy seed was explicitly dependent on the volume of capsules.
As compared with controls, the number of poppy heads per pot increased significantly and/or highly significantly with the increasing dose of nitrogen. The highest increase of number of the capsules per pot was observed after a single dose of nitrogen at the beginning of growing season (Variant 3 with 6.75 and 1.68 capsules per pot and per plant, resp.). As compared with a single dose of 0.9 g N per pot (Variant 3), partitioned applications of the total dose of 0.9 g N per pot (Variants 4–6) decreased statistically highly significantly the number of capsules per pot.
The content of morphine in capsules after the harvest (empty capsules + 15 cm of the stem) increased with the increasing supply of N fertilisers up to 1.01% (Tab. 3). This observation corresponded with a number of literature data, which showed the dependence of increasing morphine concentrations on the increasing supply of N fertilisers (Yadav et al. 1984). Kharwara et al. (1988) mentioned that the content of this alkaloid was increased when the supply of 75 kg N ha-1 was
doubled. Schrodter (1965) demonstrated increased levels of morphine at doses of 50–60 kg N ha-1 and an adequate supply of P and K. Although the cultivar Opál is
considered to be a variety with the medium content of this alkaloid (with an average concentration of 0.56%; Cihlář et al. 2003), the control variant contained 0.78% of morphine. In variants with the highest total doses of N (Var. 3–6) the highest concentrations of this alkaloid were recorded (0.91–1.01%) but without any more marked relationship to and/or dependence on the date of N application. The content of morphine was influenced above all by the cultivar; all other factors showed more or less irregular effects. This obviously caused that the increasing doses of N showed positive effect also under optimum humidity conditions. This corresponded with data published by Laughlin et al. (1992) who mentioned that morphine contents increased by 10–24% depending on precipitation and that under conditions of a rainfall deficit, the N-fertilisation did not influence significantly the content of morphine while under conditions of full water capacity its content was increased by as much as 8.8%.
Conclusions
The results of one-year pot experiments indicate that a split application of nitrogen shows positive effects on nutrition of poppy (Papaver somniferum L.).
As compared with a single application of the same dose of nitrogen, positive effects of partitioned doses were manifested above all in the increasing seed yields (by 7.23–44.42%). The highest yield effect was reached after the application of 1/3 of the N dose in the period of flowering. The partitioned application of N was reflected also in a lower number of capsules per pot and/or plant. The increase of nitrogen fertilization from 0.6 to 0.9 g N per pot increased volume of poppy capsules and the morphine content in capsules.
The presented study is a part of research project of the Faculty of Agronomy, Mendel University of Agriculture and Forestry in Brno of the Czech Ministry of Education, Youth and Physical Training – CEZ 2.308/98:432100001.
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