1,720,969 research outputs found
Life Cycle Assessment for Evaluating On-farm Energy Production: The Case of Sunflower Oil
Full text linkThe main objective of this work was to evaluate the production of sunflower oil as a source of bioenergy and its use on the farm. Representative farms of the Veneto Region were analyzed in order to evaluate the possibility of using different biofuels. The results showed that there are only a few feasible alternatives at farm level. The conversion of oil to biodiesel appeared unachievable because of the large number of hectares necessary for optimizing use of the transesterification equipment. A life cycle environmental analysis (LCA) was applied to eight different farm types simulating the total replacement of diesel oil by pure vegetable oil (sunflower). The results were not uniform because, considering all the LCA impact categories, some of them turned to be worse than the original scenario (use of diesel oil) but there was a substantial advantage for all the farm types in terms of reduction of substances with effects on climate change. Some farms, termed horticultural farm large, unspecialized farm large and unspecialized farm small, had a reduction of more than 99% in the substances with effects on climate change by changing from diesel oil to sunflower oil. The biofuel is not yet competitive as no free market exists for it, but it represents a practical way to avoid the shift of economic benefits from agriculture to industry, as happens with biodiesel production
Nuova procedura per la normalizzazione di dati sperimentali: applicazione alla traspirazione e all'espansione fogliare in girasole
No full textPortici (Napoli) 16-18 Settembre 2003
Contribution of soil to CO2 balance in industrial oil crops
No full textAbstract
The introduction of a oilseed crop, for energy production, in crop rotations typical of Northern Italy is very helpful for mitigating greenhouse effect; CO2 balance for oilseed crops being always positive as stated by Bona et al. (1999). Very little is known on CO2 evolution from cultivated soils. This incertitude is related to the fact that for producing more energy is necessary to increase input levels (tillage, chemicals ...) which very often induce an increase in soil organic matter degradation. On the other side, an extensive management can slowdown soil organic carbon degradation but the quantity of crop residues produced in this case are lower. In this framework it is necessary to find out the most suitable level of crop management for maximizing the CO2 balance.
In the present work the results of some simulations carried out with a model of CO2 evolution from soils (DiSOS model – Bona et al., 2003) applied to sunflower and rapeseed for oil production as a function of soil tillage level are reported. The model was used to simulate the soil organic carbon evolution from 400 cultivations of rapeseed and sunflower which came from a survey made in the Veneto Region (Po valley – northern Italy).
The CO2 balance showed the relative weight of soil tillage and the amount of crop residues in determining soil carbon budget. The main factor influencing this budget was the amount of crop residues thus underlining the relevance of reaching high yields. The tillage inputs resulted less relevant in this context
Herbicide dissipation and dynamics modelling in three different tillage systems
No full textThe half-lives (t50) of the herbicides metolachlor, terbuthylazine and isoproturon and the occurrence of desethyl-terbuthylazine and monomethyl-isoproturon were measured in soils managed with three different tillage systems (conventional tillage, ridge tillage and no tillage). The first-order dissipation model was well adapted to the field data. Under the trial conditions, characterised by silty soil, scarce permeability, and reduced rainfall, the tillage system did not substantially influence the dynamics of the herbicides; the t50 was reduced in no tillage only with metolachlor, the more volatile herbicide. The measured concentrations were then compared with those calculated with SoilFug, a fugacity-based mathematical model; the calculated values approximate the kinetics of both herbicides and metabolites with good precision
Gir@net: prototipo on-line per la simulazione della fenologia della resa e dello stress idrico in girasole.
No full textPortici (Napoli) 16-18 Settembre 200
Ecological interpretation of weed flora dynamics under different tillage systems
No full textIn northern Italy, on soil managed with three different tillage systems (conventional tillage, ridge tillage, and no-tillage) and submitted to standard cultural practices (crop rotation, and chemical weed control), the weed vegetation was assessed at the beginning of the trial (1987) and after six, and eight years. The aims were to evaluate (1) the effect of tillage systems on the weeds; and (2) the possibility of linking the floristic changes under reduced disturbance to the theory of ecological succession. The weeds were categorised according to life-forms (biological groups), periodicity types (ecophysiological groups), dispersal types and seed longevity. Data were analysed using Sørenson's Indices of Similarity, the Independence test, and Principal Components Analysis. The tillage systems profoundly altered the weed community: in undisturbed soils the importance of the geophyte and hemicryptophyte species, and among the annuals, Digitaria sanguinalis, Conyza canadensis and Kickxia elatine increased, as well as that of the wind-dispersed weeds. The species linked to disturbance were annuals and in particular Amaranthus spp., Chenopodium album and Echinochloa crus-galli. After eight years the floristic evolution in the reduced tillage system can be interpreted on the basis of ecological succession. The community that has formed assumes, from the quantitative point of view, characteristics of a pioneer community of secondary succession with a predominance of annual species and a large number of wind-dispersed plants. Qualitatively there is a movement towards a more mature community that could become similar to that of the woodland edge, with more perennial species, shrubs, and bird-dispersed plants. The implications of these conclusions are discussed in terms of weed management
Contribution of soil to CO2 balance in industrial oilcrop productions
No full textBologna May 15-16, 2003
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