Summary
The rape cultivation in Poland may be increased as a result of striving after meet-ing the requirements formulated in the European Union directives concernmeet-ing the production of energy from renewable sources and of a growth of the biofuel consump-tion. The production of biofuel from rape might be a chance to rehabilitate biode-graded lands and wasteland, and might have an essential impact on mobilization of rural areas.
Keywords: renewable energy, biofuels, fitoremediation, rape 1. Introduction
The prospects of the exhaustion non-renewable organic fuels, the expected increase in energy consumption by almost 52% in all world countries, and introducing stricter standards concerning the environmental protection cause a growing interest in alternative and renewable sources of en-ergy.
The fundamental assumptions of the Polish doctrine, published in 2005, concerning energy pol-icies, apart from diversification of sources, account for the issues of logistic-organizational limita-tions. Therefore, we have put forth a proposal to introduce the following regulations:
1. A constitutional principle of economic progress based on the idea of sustainable development. It is reflected in the National Development Plan. It is considered to be the basic rule of harmo-nious energy management, in the conditions of social market economy. (…)
2. Mechanisms of the competitive market are the basic mechanisms of the energy market func-tioning, together with administrative regulation in those its areas where competition is currently considerably limited. (…)
3. Supporting the development of renewable energy sources and those referred to as associated, including dispersed generation with the use of market mechanisms.
4. Autonomy of energetic policy in accordance with competences and thereby responsibility of the government administration and the local administration for its implementation, as well as their cooperation in solving common problems.
5. Responsibility of the government administration for carrying out tasks, which are inspiring and support energy production companies, on a regular basis, and in individual cases – provid-ing help accordprovid-ing to general rules.
6. Mainstreaming the idea of public-private partnership at the regional and local level, for in-vestments connected with providing energy and fuel distribution and supply services, espe-cially for the development of renewable sources of energy and associated production of electric energy and heat.
7. Consistent implementation of the rule of regulating Third Party Access as a basic tool of dis-mantling monopolies and liberalizing natural monopoly of network companies1”.
In order to achieve the objectives and fulfill the European Union directives (2001/77/WE, 2003/30/WE) concerning the production of energy from renewable sources and determining the amount of biofuels in total sales of petrol and diesel to be no smaller than the 5.75%, the area of rape cultivation should be increased to about 1.5 m. ha. At present, this plant is cultivated on 810 thousand ha and its crop amounts to 3.80 t/ha [6].
Such a great demand for rapeseeds will make producers cultivate this plant on fields that are currently uncultivated because of their anthropogenic contamination. It provides a chance to reclaim the areas located in highly industrialized regions close to big chemical plants, mines, power stations and mills, which are distinguished by a high content of heavy metals [3], [5] as well the areas that were formerly state farms. That refers especially to the north and southwestern areas of Poland, where the soil contamination indicates the necessity of excluding the area from cultivating edible plants.
2. Biodiesel from rape as an opportunity for Polish agriculture
The high content of heavy metals in soils can be found in approximately 10% of the land in Poland [8], and that which is contaminated accounts for approximately 0.5% of the arable lands in Poland [1]. As a result of cultivating plants on soils with a greater above normal content of heavy metals, poorer crops are obtained. These crops are characterized by features which fail to meet food production and processing standards as they may pose a serious health threat to of people and ani-mals [4], [8], [2].
Using these soils for rape cultivation will contribute to their phytoremediation – gradual reduc-tion in intoxicant concentrareduc-tion and will allow them to be used to produce food and foodstuffs.
It has been empirically proven by [7]2 that it is possible to apply rape in the process of phytore-mediation of soils contaminated with heavy metals.
1 On 04.01.2005 the government passed the perspective development plan with the title: “Energetic politics in Poland till
2025”. In this document, the growth of using the final energy up around 48-55% till 2025 is predicted, assuming an average annual growth in the economy at the level of 5.2%. In this paper, select parts of the document are quoted.
2 The research that was carried out was partially funded by the budget resources of the Kujawsko-Pomorskie Province within
the framework of the task named the ‘Regional Fund of Research and Implementation’ –agreement no. IG.I. 3020-UDOT-765/2007.
3. Research methodology
Seeds and vegetative organs of doubly-improved spring rape of the Heros variety were used as the research material. They were collected in the third part of July 2006. A vase experiment was conducted in a completely random arrangement in four series, in soil belonging to a good wheat complex – light clay mixture (according to PN-R-04033). Fertilizers containing nitrogen, phospho-rus, potassium and magnesium were applied before sowing in the spring, together with doses of heavy metals (zinc, copper, lead and cadmium). Analytically pure chemical reagents were applied for fertilization. The soil, which had been previously prepared, was weighed and then put into con-tainers – ten kilogrammes into every container. The rapeseeds were planted in the second part of April, and after sprouting, the selection was carried out, leaving 8 identically developed seedlings.
Developing plants were watered with distilled water according to their needs, while the soil moisture was kept at the level of 60% of the field water capacity. A chemical protection for rape against pathogens and pests was applied. The contents of fatty acids (palmitic, stearic, oleinic, lino-leic, linolenic, eicosenoic and erucic acids) in the oil obtained from seeds were determined after previous oil extraction in accordance with the PN-76/R-64753 method and after transesterification. The analysis of methyl derivatives of fatty acids was carried out with the use of gas chromatography. The labels were made by IHAR in Pozna. During the soil tests, the granulometric composition, acidity, the sum of alkaline cations, the content of organic carbon and nitrogen were marked by the aerometric method at the beginning of the experiment and after 18 months.
The Lindsay and Norvell method was applied to determine the content of forms of metals that were assimilable for plants. In order to determine the total content of heavy metals, the soil samples were mineralized in a mixture of hydrofluoric acid and chloric (VII) acid, whereas the plant material was mineralized in a microwave oven in a mixture of HNO3 mixture and H2O2. After mineralization, the content of the metals forms (DTPA) assimilable for plants, and the total content of zinc, copper, lead and cadmium in the soil was determined by applying the method of atomic spectroscopy with a PU 9100 Philips device, whereas the content of zinc, copper, lead and cadmium in the plant mate-rial (seeds, leaves, stalks and roots) was examined by applying the method of atomic emission spec-trometry with inductively coupled plasma (ICP) with a Jobin Yvon Emission JY38S device. The cost calculation of the biofuel production was performed by applying source materials acquired from Zakłady Tłuszczowe “Kruszwica” S.A., the POCH S. A. Company, ENEA Operator Sp. z o.o. – Biuro Sprzeday Usług Dystrybucji, and from the Law Gazette (Dziennik Ustaw) 2009 no. 3 poz. 11 (Art. 89.1).
4. Research findings
No essential influence of the applied doses of heavy metals (zinc, copper, lead and cadmium) on chosen agrotechnological parameters of the crop of rapeseeds was found in the plant material collected from the vegetative containers. The highest crop of seeds (5.33 g) was collected from the plants cultivated in containers in soil contaminated with zinc at a dose of 600 of mg·kg-1 of soil, and the lowest (4.48g) in the case of rape cultivated on the soil contaminated with cadmium at a dose of 6 mg·kg-1 of soil. It was found that the mass of 1,000 seeds was the highest (3.11 g) in the rape collected from the containers filled with the soil contaminated with copper at a dose of 80 mg·kg-1 of soil and the lowest (2.77 g) in the case of rape collected from the containers consisting of soil with cadmium at a dose of 2 mg·kg-1 of soil. In the case of soil with copper at a dose of 80 mg·kg-1
of soil, the highest mass of one seed was 3.10 mg, and when the soil was contaminated with cadmium at a dose of 2 mg·kg-1 of soil, the mass of a seed was the lowest at 2.77 mg.
The rest of the agrotechnological parameters of the crop, i.e. the number of seeds from the container and the number of seeds from the plant were the highest in the case of rape gathered from containers contaminated with zinc at a dose of 600 mg·kg-1 of soil and the lowest in the case of rape gathered from soil contaminated with cadmium at a dose of 6 mg·kg-1 of soil.
The highest content of zinc was found in leaves of the rape growing in containers consisting of the soil in which zinc is at a dose of 600 mg·kg-1 of soil. Also, in case of copper, its highest content was recorded in these organs: they contained 9.74 mg·kg-1 s.m. However, the largest amount of lead (113.83 mg·kg-1 s. m.) was found for the roots of the rape that was growing in the soil containing 1600 Pb·kg-1 of soil, while the largest amount of cadmium was discovered in the stems of the rape collected from containers filled with the soil contaminated with this element at a dose of 6 mg·kg-1 of soil. These organisms contained 5.94 mg Cd·kg-1 s. m.
The process of rape biofuel production consists of pressing the rape oil from seeds with a plug screw feeder. Next, the re-estrification of the obtained rape oil involved replacing glycerin with methanol. In this way, the methylic esters of fatty acids obtained are used as biofuel in diesel engines and in numerous by-products, such as glycerin and soap. These compounds are separated from bio-fuel, and it is possible to use them in the pharmaceutical and cosmetic industry. This process occurs at a temperature of about 65-70ºC in presence of KOH.
The production of biodiesel from rape should enable the partial independence of farms from the global fluctuations of fuel prices, which would contribute to increasing their competitiveness and farming growth profitability3.
Using biofuel that was produced in agrorefineries for the diesel engine, apart from the economic aspect, has a great ecological significance compared to traditional diesel. Among these advantages are:
- reduction in the emission of SO2 and CO2, that decreases the occurrence of acid rain and the greenhouse effect,
- reduction in the amount of fumes,
- lower content of CO, HC and carcinogenic compounds in fumes, - lack of an acrid and toxic impact on human and animal organisms, - total decomposition in the environment over 21 days,
- better lubricant properties.
3 The approximate cost of producing 1 dm3 of biofuel will amount between 5.23 zloty to 5.28 zloty. In this calculation, the cost
of 3 tons of rapeseeds was taken into consideration (the purchase price for 1 ton = 1890 zloty net) and 200 litres of methanol (200 litres = 660 zloty net), 21 kg of the reaction catalyst (21 kg of KOH = 180 zloty net) and 40 KWh of electric energy (1KWh ≈ 0,3119 zloty per month net). Calculating the biofuel price, it was assumed that rapeseed meal that was obtained during the production process – 2 tons would be sold at the cost of 1400 zł • t-1 net. To this price, the excise tax was also added – 10 zloty for every 1000 litres of the biofuel produced. The calculation did not take into consideration the cost of purchase and amortization of the installation for producing biodiesel and the sale of glycerine and soap.
5. Proposal of rape cultivation technology
Promotion of modern methods of the rape cultivation involves increasing the area of agricultural lands where the rape is to be planted. Winter rape, as well as the spring one, should be cultivated on medium-compact soils, with a reaction close to neutral (pH 5.8–6.5), rich in humus, and with a great ability to gather water. These are mainly soils belonging to the very good as well as good wheat complex and to a very good rye complex. A good crop of rapeseeds in lighter soils could be achieved only if they are watered well after a good forecrop and with slightly higher fertilizing.
Dry soils of the weak and very weak rye complex are definitely not suitable for cultivating winter and spring rape. The best forecrops for rape are:
- potatoes in manure, early varieties in case of winter rape, - clover,
- leguminous plants gathered from fields early in case of winter rape, - blends of papilionaceous plants with grains planted as feed, - barley planted to acquire seeds.
Winter rape growing, in case the forecrops are cereals, perennial papilionaceous plants or leguminous and cereal blends involves ploughing to a depth of 6–8 cm, which prevents the loss of soil humidity, enables faster sprouting of weed seeds and stops the development of diseases and pests. Depending on the intensity of sprouting weeds, the field after the first ploughing should be harrowed once or twice in six or seven day intervals. After the forecrops leave the sod field, cultivation should precede the first ploughing. After the forecrops, when the field is left free of weeds, e.g. bulb and root plants, pea and fodder blends as well as alkaline cations, cultivation or using a disc harrow should be applied rather than the first ploughing, and then sowing ploughing should be carried out at a depth of 18–25 cm, two or three weeks before the planned sowing. If sowing ploughing is delayed, rolling should be carried out in order to accelerate the soil subsiding. The pre-sow cultivation of the soil consists in aerating it to a depth of approximately 4 cm using a harrow and string rollers.
In the period of pre-sow cultivation, the best solution is to apply samples before the first ploughing - of an entire dose of a phosphorus-potassium fertilizer (P2O5 about 60–130 kg
ha-1 and K2O at a dose of 140–180 kgha-1) and a part of nitrogen (about 20–30 kg N · ha-1), mainly on soils that are poor in this element which guarantees that it will mix well with the soil. In the case of cultivating rape in acidic soil (a pH under 6.0), liming should be applied: the best being carbonate lime at a dose of 20–25 dtha -1. Liming is carried out immediately after gathering the forecrop, and then the complete set of aftercrop and pre-sow cultivation is carried out. In acidic soil having low magnesium content (below 5 mg in 100 g of the soil), 100 kgha-1 of kieserite or magnesium sulphate should be applied before sowing the dose of 150 kgha-1. The doses of mineral fertilizers should be best specified based on the findings of the soil examination carried out by the Okrgowe Stacje Chemiczno-Rolnicze Regional Chemical Farm Stations. For determination of the doses of the foreseen crop of rapeseeds, it is necessary to take into consideration the time that passed from the last fertilization using manure.Sowing seeds of winter rape is carried out in the second half of August: planting 4–5 kg
ha-1 of seeds at the depth of 1.5 – 2 cm, with the distance between rows of 10–14 cm, and eliminating weeds only with the use of herbicides. It is possible to link the fight against weeds by fertilizing with nitrogen, e.g. spraying with a 5–10 % solution. The first foliar feeding of winter rape might be carried out when the rape develops 6–8 leaves, that is, right before covering the area between rows; whereas the optimaltime of foliar feeding of winter rape is the period of spring vegetation - that is since restarting vegetation till the beginning of rape blowing. The last foliar feeding in the period of vegetation might be carried out on green shuck immediately after shed blossoming of the rape. The total dose of nitrogen applied in the form of foliar feeding should not exceed 220 kg N ha-1. Rape is a sulfophilic plant, taking up approximately 40–80 kg S · ha-1; therefore, one should remember to apply foliar feeding with this element in the sulphate form (NH4SO4, MgSO4) or in its elementary form at a dose of about 60–100 kg S · ha-1. The best solution is to apply this element as foliar feeding in the form of ammonium sulphate in the dose of 120–180 kg
ha-1. Thanks to the application of ammonium sulphate, the plant is provided with the sulphur and nitrogen essential for its normal growth and development.In the case of cultivating the spring rape, it is a mistake to establish a rape field next to an existing winter rape field because of the migration of pests. The soil requirements of the spring rape are similar to those of the winter varieties. Acid soils should be limed by applying the lime under the forecrop or after gathering it to the stubble. After the plants leave the stubble, the first ploughing and harrowing should be carried out. On heavy soils, phosphoric and potassic fertilizing should be applied in the doses of 30–60 kg
ha-1 P2O5 and 60–120 kgha-1 K2O before winter ploughing carried out at the depth of 20–25 cm. On the field where potatoes were grown, ploughing might be shallowed to 15 cm. In early spring, the soil should be aerated in its top layer in order to stop the evaporation of water through harrowing. Fundamental cultivating treatments are carried out in the spring just before sowing using a cultivator with stiff feet with a harrow or a cultivator connected with a string shaft in order to loosen the soil to a depth of 2–3 cm. Apart from loosening the soil this treatment is aimed at mixing the soil with nitrogen applied before sowing in the dose of 40–60 kg N · ha-1. The rest of the nitrogen dose (80–100 kg N · ha-1) is applied after rape sprouting as foliar feeding in the form of ammonium sulphate. The seeds are sowed in the amount of 4–5 kgha-1 at a depth of 1.5–2 cm, in a row gauge of 10–14 cm and after the chemical destruction of weeds. The harmfulness of diseases in the spring rape is lower than in the winter rape for many reasons, including its shorter vegetation period. 6. Conclusions
The research findings indicate the possibility of using rape in the phytoremediation of areas contaminated with zinc, copper, lead and cadmium, whereas the interactions of these elements which may occur in the soil, as well as in a plant, were not taken into consideration in this experiment. It was proved that the applied doses of heavy metals had not influenced the percentage content of protein and fat in the collected seeds of spring rape. The lack of the influence of applied doses of zinc, copper, lead and cadmium on the percentage content of fat in seeds and fatty acids in oil which was extracted from them is advantageous from the point of view of their technological usage for biofuel production. An essential influence of the applied doses of heavy metals on their content in the examined interior rape structure was found. Indeed, the lowest contents of zinc and copper were discovered in the seeds, leaves, stalks and roots of the rape collected from the test containers. The examined inner structure of the test plants did not contain lead or cadmium. Spring rape takes up zinc, copper, lead and cadmium from the soil and accumulates these elements in vegetative organs and seeds. Therefore, seeds collected from plants growing in soil contaminated with heavy metals should be used for biodiesel production in small and medium refineries located within close proximity. However, they should not be used for the production of cooking oil.
The production of biodiesel in small and mid-sized refineries with an annual processing from 0.5 to 1.5 thousand tons of seeds may contribute to a significant improvement in the economic situation of Polish rural areas by reducing overmanning in the agricultural sector, which is currently assessed at approximately 2.2 million of people. They will find employment in refineries or companies dealing with the processing and distribution of production-waste rape meal and of by-products (e.g. glycerin). It is possible to obtain about 0.33 ton of ester biofuel and 0.67 ton of oil meals from 1 ton of rapeseeds in an agrorefinery. Assuming the average yield at the level of 3.0 ton from a hectare, it is feasible to produce about 1.0 ton of biodiesel, which will meet the annual demand for fuel of a farm with an area of 10 ha.
According to the research, it seems to be justified to aspire to fulfill the criteria included in the European Union directives that assume an increase in the production of energy from renewable sources. One of the chances might be the increase of rape cultivation in Poland. These crops cannot be used as food, but they can be successfully processed as a material for biofuel production. However, the condition of developing such a production is the growth of biofuel consumption (stimulated by tax and excise concessions, which will reduce the final price of biofuel). The production of biofuel from rape might be a chance to rehabilitate biodegraded areas and wastelands, and it may also have an essential influence on the mobilization of Polish rural areas.
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BIODIESEL Z RZEPAKU – ZRÓWNOWAĩONY ROZWÓJ I EKOLOGIA Streszczenie
Sprostanie wymaganiom zawartym w dyrektywach unijnych dotyczcymi produk-cji energii ze ródeł odnawialnych oraz wzrostu zuycia biopaliw moe wpłyn na zwikszenie udziału upraw rzepaku w Polsce. Produkcja biopaliwa z rzepaku moe by szans na rekultywacj terenów biozdegradowanych i nieuytków oraz mie istotny wpływ na aktywizacj obszarów wiejskich.
Słowa kluczowe: energia odnawialna, biopaliwa, fitoremediacja, rzepak
Piotr Szulc Anna Mojzesowicz Grzegorz Dziea Marek Sikora
University of Technology and Life Sciences in Bydgoszcz e-mail: zis@utp.edu.pl
