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Abstract: Cover crops can reduce the use of external inputs such as pesticides and fertilisers and can at the same time suppress weeds as well as improve or maintain soil fertility. Cover crops can also modify the microclimate which affects pest populations and diseases. Determining cover crop species and management practices is based on the needs and goals of production. The effects of introducing living mulch (LM) and management strategies on cash crop yield, product quality and energy use were studied in certain European countries (Slovenia, Italy, Germany and Denmark) in different climatic and soil conditions. In Slovenia, in organic production of cauliflower and leek, the effects of two terms of sowing white clover with additive design were compared with a production with black foil and with the usual agricultural practice by hoeing. In the field experiments the effect of LM on arthropod dynamics and activity density was investigated. The results demonstrated that the LM systems with a substitutive design, can be effectively implemented in vegetable production if the value of the ecological services (positive externalities) delivered by LM can counterbalance the yield loss due to the cash crop density reduction. If an additive design is used, the LM should be sown several weeks after the cash crop planting. Different cash crop genotypes (i.e., open pollinated/local cultivars in comparison with the hybrids) performed similarly. Use of human labor (HL) and fossil fuel (FF) energy slightly increased in LM systems (7%). The farmers’ acceptance of the LM techniques was quite high (75% of the interviewed sample). The LM technique did not affect the infestation of cabbage caterpillar Pieris spp., showing no detrimental effect of this technique on this key pest of cabbage. In Denmark, aphid populations were higher in the sole crop system than in the LM system. In Italy, a level of larval parasitization was detected and in the first year the percentage of parasitization was higher in LM (88%) than in sole crop (63%). Overall, the LM positively affected the activity density of Carabid beetles, also increasing the diversity and evenness of species (Slovenia and Italy) or activity density of some taxa (Slovenia and Denmark). Due to numerous agroecological services of cover crops, growing simultaneously with vegetables as LM, this could be promising technique for organic and others production systems in the future.
Keywords: organic vegetable production, cover crops, agroecological service, living mulch, energy consumption, biodiversity, soil arthropod
Published in DKUM: 01.02.2019; Views: 1679; Downloads: 229
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Abstract: The Western Australian economy has always been underpinned by farming and mining. Over the last five years the economy has experienced phenomenal growth due to unprecedented global demand for resources and increasingly, agricultural land is being given up for mining. Changing land uses challenge industry and community leaders; some communities are overwhelmed by a new population connected with mining, bringing with it a range of social and economic tensions that small communities struggle to cope with. This paper will discuss the conflicting issues regarding land use planning, local and environmental governance and sense of place while also canvassing positive developments that have enhanced community and regional economic development, thus building a resilient future.
Keywords: regional economic development, mining and energy sector, agricultural production, Australia
Published in DKUM: 26.03.2018; Views: 2244; Downloads: 80
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Abstract: This paper presents a method for determining energy production of Cadmium-Telluride photovoltaic system, which has a different working performance than the most used Silicon photovoltaic systems. The main difference is sensitivity to the temperature and the solar irradiance. The CdTe cells are less sensitive to the temperature and in contrast to the Si Cells they have a higher efficiency at lower irradiance.
Keywords: photovoltaic module, energy production, annual energy yield, Cadmium-Telluride
Published in DKUM: 10.07.2015; Views: 1506; Downloads: 67
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Keywords: polymers, polyethylene terephthalate, structural analysis, structure, ethylene, PET, commercial policy, production, system examined, ecology, presentation, profiles, results, tables, methodology, energy
Published in DKUM: 01.06.2012; Views: 1676; Downloads: 51
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Abstract: Fuel-cell efficiencies yield substantial reductions in the emissions of climate-change gases and promise an end to exclusive reliance on carbon fuels for energy. Fuel cells, CO2 reuse, process heat integration, and open gas turbine electricity cogeneration can be optimized simultaneously, using a nonlinear programming (NLP) algorithm. The simplified NLP model contains equations of structural and parametric optimization. This NLP model is used tooptimize complex and energy-intensive continuous processes. This procedure does not guarantee a global cost optimum, but it does lead to good, perhaps near-optimum, designs. The plant, which produces methanol, has a surplus of hydrogen (H2) and CO2 flow rates in purge gas. H2 is separated from the purge gas by an existing pressure swing adsorption (PSA) column. Pure H2 can be usedas fuel in fuel cells. CO2 can be separated from the outlet stream (purge gas) by a membrane or absorption system (absorber and regenerator) or an adsorption system and reused as a reactant in a reactor system. Therefore, theproduct yield can be increased and CO2 emissions can be reduced, simultaneously. CO2 emissions can then be reduced at the source. The retrofitted process can be operated within existing parameters. Using a methanol process as a case study, the CO2 emission flow rate can be reduced by4800 t/a. The additional electricity cogeneration in the gas turbine and in fuel cells and additional flow rates of the raw material could generate an additional profit of 2.54 MEUR/a.
Keywords: chemical processing, methanol production, optimization, nonlinear programming, CO2 reuse, fuel cells, heat integration, energy cogeneration
Published in DKUM: 31.05.2012; Views: 2284; Downloads: 111
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