Tag Archives: energy input

1316-1327 V. Zagorska, A. Ruciņš, D. Viesturs and S. Ivanovs
Assessment of the greenhouse gas emissions and energy inputs applying different weed control methods for wheat growing
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Assessment of the greenhouse gas emissions and energy inputs applying different weed control methods for wheat growing

V. Zagorska¹*, A. Ruciņš², D. Viesturs² and S. Ivanovs²

¹Latvia University of Life Sciences and Technologies, Institute of Plant Protection Research ‘Agrihorts’, 2 Paula Lejiņa street, LV–3001 Jelgava, Latvia
² Latvia University of Life Sciences and Technologies, Ulbroka Research Center, 1 Instituta street, LV–2130 Ulbroka, Latvia
*Correspondence: viktorija.zagorska@llu.lv

Abstract:

Economic indicators are often used to evaluate and select technologies, determining the production costs of the product. However, according to the EU’s green course, the ecological assessment of technologies is increasingly important. The purpose of the article is to comparatively evaluate two winter wheat weed control methods, which are widely used in Latvia, according to two ecological indicators – the amount of the GHG emissions and the energy consumption, to find out whether these indicators can serve as a criterion for the selection of technologies. These two methods are HA (harrowing), in which weeds are controlled by harrowing and herbicides, HE (herbicides), in which weeds are controlled only by herbicides. The methodology for calculating the mentioned indicators was developed by analyzing several studies by other authors. The total GHG emissions generated are calculated as the sum of five components: emissions, generated for the manufacture and delivery of the machinery used; emissions, generated by the fuel, consumed for implementation of the technology; emissions, generated for the production, delivery and installation of fertilizers; emissions, generated for the production, delivery and installation of pesticides, seed production, delivery and installation emissions. Analogously, the total energy consumption is calculated by summing the components The technologies were implemented on a specific farm, with the machinery of this farm, labor, fertilizers and the plant protection products. It has been established that the technologies differ by the calculated ecological indicators within the range of 1.2–2.6%; moreover, these indicators are lower for the technology with the herbicide spraying, and the technology is simpler to implement. Therefore, it is also more widely used. Since the coefficients for the calculation of the ecological indicators can be applied by the methodology of this article, the characteristics of the technique and the doses of fertilizers and the plant protection agents, used on the farms, are known, the ecological indicators can be used as an additional criterion for the selection of technologies on the farms. The ratio of the energy value and energy consumption of the produced product (the output and the input ratio) was also determined, this indicator for technologies HA and HE being, respectively, 8.30 and 8.41. In comparison with the research by the authors in other countries, from the point of view of the amount of the generated CO₂-eq emissions and rational consumption of energy, the analysed winter wheat production technologies are evaluated as moderately efficient, but from the point of view of the energy value of the product produced and the ratio of the energy consumption (the output and the input ratio) – as efficient.

Key words:

energy input, energy output, GHG emissions, technologies, wheat growing

229-239 A. Kryževičienė, A. Jasinskas and A. Gulbinas
Perennial grasses as a source of bioenergy in Lithuania
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Perennial grasses as a source of bioenergy in Lithuania

A. Kryževičienė¹, A. Jasinskas² and A. Gulbinas²

¹ Lithuanian Institute of Agriculture, Instituto al.1, LT-58344 Akademija,Kėdainiai reg., Lithuania; e-mail: akryzeviciene@lzi.lt
² Institute of Agricultural Engineering Lithuanian University of Agriculture,Raudondvaris, LT-54132 Kaunas reg., Lithuania; e-mail: aljas@mei.lt

Abstract:

The study was designed to investigate the feasibility of cultivating perennial grasses as energy crops and their effect on soil agroecological potential. Field experiments with different grasses were conducted at the Lithuanian Institute of Agriculture from 2000–2004. Perennial grasses Phalaroides arundinacea L. and Bromopsis inermis Leysser were grown pure and in mixtures with legumes. Melilotus officinalis, Lupinus polyphyllus and Galega orientalis on a light gleyic loam soil (Cambisol) with a humus content of ca. to 2%. Pure swards of grasses were either fertilized with nitrogen or not. Mixtures did not receive any N. The swards were cut once per season when their biomass was used for combustion, and twice per season when their biomass was used for biogas. Dry matter yield of grasses in pure stands ranged from 6.4 to 9.3 t ha-1. Under normal weather conditions grass-legume mixtures without nitrogen (N) fertilization were higher yielding than N-fertilized (60+60 kg N ha-1) grass in pure swards, but the mixtures were lower yielding in the years with inadequate rainfall. In all cases mixtures had an important ecological advantage over N-fertilized grass swards. The swards had a positive soil conservation effect and maintained soil fertility potential.The energy potential of perennial grasses in both cases of biomass utilization variedaccording to DM yield variation and totaled up to 153 GJ ha-1; energy input for biofuel production amounted to 8.0 – 19.2 GJ ha-1. Our experimental evidence suggests that the tested swards sown on less fertile soil, amounting to over 0.5 million ha in Lithuania, would be able to produce to 4 million tons of biomass for energy production annually.

Key words:

biofuel, biomass, energy input, energy potential, perennial grasses

37-45 A. Jasinskas, G. Rutkauskas, B. Kavolėlis,A. Sakalauskas and E. Šarauskis
The energetic evaluation of technologies for fuel preparation from grass plants
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The energetic evaluation of technologies for fuel preparation from grass plants

A. Jasinskas¹, G. Rutkauskas¹, B. Kavolėlis¹,A. Sakalauskas² and E. Šarauskis²

¹Institute of Agricultural Engineering of Lithuanian University of Agriculture,Institute St. 20, LT-54132 Raudondvaris, Kaunas distr., Lithuania; e-mail: aljas@mei.lt
²Department of Agricultural Machinery, Lithuanian University of Agriculture,Studentu St. 15A, LT-53361 Akademija, Kaunas distr., Lithuania;e-mail: ZUM.katedra@lzuu.lt

Abstract:

The technologies of growing, harvesting and preparing for fuel traditional feed type grasses (the mix of cereal and legume grasses) and coarse-stemmed vegetative plants (topinambours and sunflowers) were evaluated and a rational technique was selected. The methods of energetic evaluation of fuel preparation technologies were reviewed.After energetic evaluation of the technologies it was estimated that the total energy inputof growing and harvesting grasses and legumes was equal to 8334 MJ ha-1, topinambour stems – 14378 MJ ha-1 and sunflower stems – 11324 MJ ha-1 respectively. The total energy input of growing and harvesting of traditional grasses was by 72% lower than that of topinambour stems and by 36% lower than the energy input required for fuel production from sunflower stems. From an energetic perspective, the technology of fuel preparation from traditional grasses is more advantageous than the technologies of fuel preparation from coarse-stemmed plants, specifically topinambour and sunflower stems.

Key words:

energy input, fuel, stems, sunflowers, technology energy evaluation, topinambours, traditional grasses