Energy flow and greenhouse gas emissions in organic and conventional sweet cherry orchards located in or close to Natura 2000 sites

An energy analysis in orchards is useful to deciding best management strategies. The objective of this study was to evaluate, by selecting organic and conventional sweet cherry orchards located in/or close to Natura 2000 sites (a) the energy flow between the two farming systems and (b) the effect of farming system to gas emissions (CO₂, CH₄ and N₂O). Twenty farms [(2-conventional and 2-organic) × 5-locations] were selected during 2003-2004. Means averaged over all locations for insecticides and fungicides application, fuel, insecticides, fungicides, non-renewable energy inputs, energy shoot outputs, energy fruit outputs, energy shoot + fruit outputs, fruit production, shoot efficiency, fruit efficiency, shoot + fruit efficiency, non-renewable energy efficiency, gas emissions were higher in conventional than in organic orchards, while fertilizer application, harvesting, fertilizers, labor, total energy inputs, renewable energy inputs, intensity and non-renewable energy consumption were higher in organic orchards. Means averaged over two farming systems for fertilizer, insecticide and fungicide application were higher in GRL2 and GRL5. The means averaged over two systems for transportation had the highest value in GRL4 and the lowest in GRL5. Finally, means averaged over two farming systems for labor had the highest value in GRL2. Non-renewable energy inputs as percent of total inputs were 82.63 and 52.42% in conventional and organic sweet cherry orchards respectively. The results show that organic farming systems could reduce non-renewable energy inputs and gas emissions in an efficient way in areas related to Natura 2000 sites.     

Energy use patterns and econometric models of grape production in Hamadan province of Iran

This paper examines the energy use patterns and relationship between energy input and yield for grape production in Malayer region of Hamadan Province. Data from 50 farmers were collected using a face-to-face questionnaire method. In the surveyed vineyards, average yield and energy consumption were calculated as 18,530 kgha⁻¹ and 45,213.66 MJha⁻¹, respectively. Among input energy sources, fertilizers, electricity and farmyard manure contained highest energy shares with 37.25%, 19%, and 17.84%, respectively. The energy ratio and energy productivity were found to be 4.95 and 0.42 kgMJ⁻¹.Three econometric models were developed to estimate the impact of energy inputs on yield. The results revealed that impact of chemical, fertilizer and water on yield were significant at 1% probability level. Also, indirect and non-renewable energies were found to be rather high. Sensitivity analysis indicated that among the inputs, chemical has the highest MPP value of energy inputs. RTS (returns to scale) values for grape yield was found to be 2.15; thus, there prevailed an IRS of grape for estimated model. The net return was found to be positive as 2810.56 $ha⁻¹ for grape. The benefit-cost ratio was calculated as 2.08.     

Energy and cost analysis for greenhouse and open-field grape production

The objective of this study was to examine the energy use patterns and cost of production in greenhouse and open-field grape production. Data used in the study were obtained from the experiment conducted at the Akdeniz university research field. In the study, energy values were calculated by multiplying the amount of inputs and outputs by the related energy conversion factors. The results indicated that total input energy use in greenhouse and open-field production was found to be 24513.0 and 23640.9 MJ/ha, respectively. However, the output energy of greenhouse grapes (73396.0 MJ/ha) was lower than open-field grapes (120596 MJ/ha). The output–input ratio for greenhouse and open-field grape production was found to be 2.99 and 5.10, respectively. The economic analysis revealed that production costs for greenhouse grapes were higher than open-field grapes but greenhouse grapes were more profitable than open-field due to premium prices for greenhouse grapes.     

Energy return on investment of Austrian sugar beet: A small-scale comparison between organic and conventional production

In near future it is essential for human society to switch its primary energy use from finite sources to renewable ones. Ethanol has been claimed to be a potential candidate to replace oil use to great extent. This study illustrates that ethanol production has the potential to rely on organic agriculture and thereby to reduce reliance on fossil fuels. Case studies were carried out by examining three farms (2 conventional, 1 organic) in Austria who are mainly producing sugar beet. We found that organic sugar beet production provided an overall energy return on investment (EROI) of 11.3 whereas the conventional farming practice showed an EROI of 14.1 and 15, respectively. Our study indicates that organic sugar beet production shows potential to substitute conventional industrial sugar beet production to provide inputs to ethanol production. By using organically produced sugar beets as inputs to the ethanol production, fossil fuels can perhaps be avoided to a large extent in the production process, thus, it may be possible to mitigate some of the environmental impacts associated with ethanol production. Larger studies are however needed to better visualise such results.     

EUE (energy use efficiency) of cropping systems for a sustainable agriculture

Energy efficiency of agriculture needs improvement to reduce the dependency on non-renewable energy sources. We estimated the energy flows of a wheat-maize-soybean-maize rotation of three different cropping systems: (i) low-input integrated farming (LI), (ii) integrated farming following European Regulations (IFS), and (iii) conventional farming (CONV). Balancing N fertilization with actual crop requirements and adopting minimum tillage proved the most efficient techniques to reduce energy inputs, contributing 64.7% and 11.2% respectively to the total reduction. Large differences among crops in energy efficiency (maize: 2.2 MJ kg⁻¹ grain; wheat: 2.6 MJ kg⁻¹ grain; soybean: 4.1 MJ kg⁻¹ grain) suggest that crop rotation and crop management can be equally important in determining cropping system energy efficiency. Integrated farming techniques improved energy efficiency by reducing energy inputs without affecting energy outputs. Compared with CONV, energy use efficiency increased 31.4% and 32.7% in IFS and LI, respectively, while obtaining similar net energy values. Including SOM evolution in the energy analysis greatly enhanced the energy performance of IFS and, even more dramatically, LI compared to CONV. Improved energy efficiency suggests the adoption of alternative farming systems to reduce greenhouse gas emissions from agriculture. However, a thorough evaluation should include net global warming potential assessment.     

Energy and greenhouse gas balances of cassava-based ethanol

Biofuel production has been promoted to save fossil fuels and reduce greenhouse gas (GHG) emissions. However, there have been concerns about the potential of biofuel to improve energy efficiency and mitigate climate change. This paper investigates energy efficiency and GHG emission saving of cassava-based ethanol as energy for transportation. Energy and GHG balances are calculated for a functional unit of 1 km of road transportation using life-cycle assessment and considering effects of land use change (LUC). Based on a case study in Vietnam, the results show that the energy input for and GHG emissions from ethanol production are 0.93 MJ and 34.95 g carbon dioxide equivalent per megajoule of ethanol respectively. The use of E5 and E10 as a substitute for gasoline results in energy savings, provided that their fuel consumption in terms of liter per kilometer of transportation is not exceeding the consumption of gasoline per kilometer by more than 2.4% and 4.5% respectively. It will reduce GHG emissions, provided that the fuel consumption of E5 and E10 is not exceeding the consumption of gasoline per kilometer by more than 3.8% and 7.8% respectively. The quantitative effects depend on the efficiency in production and on the fuel efficiency of E5 and E10. The variations in results of energy input and GHG emissions in the ethanol production among studies are due to differences in coverage of effects of LUC, CO₂ photosynthesis of cassava, yields of cassava, energy efficiency in farming, and by-product analyses.     

Energy and carbon footprints of ethanol production using banana and cooking banana discard: A case study from Costa Rica and Ecuador

Banana and cooking banana (Musa spp.) production systems accumulate a considerable quantity of discard due to high quality demands of markets. Ripe fruits have high sugar contents, which can be easily processed to ethanol. The present study aimed to quantitatively assess the production potential of ethanol from Musa spp. discard and to analyze the energy and carbon (C) footprints of this production system using a life cycle approach. The study compared three case studies differing in management practices, which were (I) a coffee producer’s cooperative in Costa Rica using Musa spp. as shade trees, (II) organic banana producers from Ecuador, and (III) conventional banana producers from Ecuador. It was found that banana and cooking banana discard accumulated at a rate of 1.4-3.4 t ha⁻¹, of which around 118-266 l ethanol could be produced on a yearly basis. The case study from Costa Rica yielded a net-energy balance (NEB) of 19.3 MJ l⁻¹ and avoided carbon emissions of 0.48 kg l⁻¹. It was closely followed by the organic banana producers from Ecuador with a NEB of 17.1 MJ l⁻¹ and avoided carbon emissions of 0.44 kg l⁻¹. NEB and avoided carbon emissions for the conventional banana farms in Ecuador were much lower (7.2 MJ l⁻¹ and 0.34 kg l⁻¹).Despite providing economic benefits to farmers through a biomass source that would have been otherwise lost, the study gave clear evidence that the ecological footprint of this ethanol production system is significantly influenced by the resource use during the production life cycle.     

Biomass energy in organic farming—the potential role of short rotation coppice

One of the aims of organic farming is to “reduce the use of non-renewable resources (e.g. fossil fuels) to a minimum”. So far, however, only very little progress has been made to introduce renewable energy in organic farming. This paper presents energy balances of Danish organic farming compared with energy balances of conventional farming. In general, the conversion to organic farming leads to a lower energy use (approximately 10% per unit of product). But the production of energy in organic farming is very low compared with the extensive utilisation of straw from conventional farming in Denmark (energy content of straw used for energy production was equivalent to 18% of total energy input in Danish agriculture in 1996).Biomass is a key energy carrier with a good potential for on-farm development. Apart from utilising farm manure and crop residues for biogas production, the production of nutrient efficient short rotation coppice (SRC) is an option in organic farming. Alder (Alnus spp.) is an interesting crop due to its symbiosis with the actinomycete Frankia, which has the ability to fix up to 185 kg/ha nitrogen (N₂) from the air. Yields obtained at different European sites are presented and the R&D needed to implement energy cropping in organic farming is discussed.Possible win–win solutions for SRC production in organic farming that may facilitate its implementation are; the protection of ground water quality in intensively farmed areas, utilisation of wastewater for irrigation, or combination with outdoor animal husbandry such as pigs or poultry.     

An evaluation of cassava, sweet potato and field corn as potential carbohydrate sources for bioethanol production in Alabama and Maryland

The recent emphasis on corn production to meet the increasing demand for bioethanol has resulted in trepidation regarding the sustainability of the global food supply. To assess the potential of alternative crops as sources of bioethanol production, we grew sweet potato (Ipomoea batatas) and cassava (Manihot esculentum) at locations near Auburn, Alabama and Beltsville, Maryland in order to measure root carbohydrate (starch, sucrose, glucose) and root biomass. Averaged for both locations, sweet potato yielded the highest concentration of root carbohydrate (ca 80%), primarily in the form of starch (ca 50%) and sucrose (ca 30%); whereas cassava had root carbohydrate concentrations of (ca 55%), almost entirely as starch. For sweet potato, overall carbohydrate production was 9.4 and 12.7 Mg ha⁻¹ for the Alabama and Maryland sites, respectively. For cassava, carbohydrate production in Maryland was poor, yielding only 2.9 Mg ha⁻¹. However, in Alabama, carbohydrate production from cassava averaged 10 Mg ha⁻¹. Relative to carbohydrate production from corn in each location, sweet potato and cassava yielded approximately 1.5× and 1.6× as much carbohydrate as corn in Alabama; 2.3× and 0.5× for the Maryland site. If economical harvesting and processing techniques could be developed, these data suggest that sweet potato in Maryland, and sweet potato and cassava in Alabama, have greater potential as ethanol sources than existing corn systems, and as such, could be used to replace or offset corn as a source of biofuels.     

Integrated harvesting of energy wood and pulpwood in first thinnings using the two-pile cutting method

In order to increase the harvesting volumes of energy wood and pulpwood from first thinnings, harvesting costs have to be reduced significantly. Metsäteho Oy studied the integrated harvesting of pulpwood and energy wood based on a two-pile method, where industrial roundwood (pulpwood) and energy wood fractions are stacked into two separate piles when cutting a first-thinning stand. The productivity and cost levels of the integrated, two-pile cutting method were determined, and the harvesting costs of the two-pile method were compared with those of conventional separate wood harvesting methods.In the time studies, when the size of removal was 50 dm³, the productivity in conventional whole-tree cutting was 6% higher than in integrated cutting. With a stem size of 100 dm³, the productivity of whole-tree cutting was 7% higher than in integrated cutting. The results indicated, however, that integrated harvesting based on the two-pile cutting method enables harvesting costs to be decreased to below the current cost level of separate pulpwood harvesting in first-thinning stands. The greatest cost-saving potential lies in small-sized (d_1.3 = 7-11 cm) first thinnings. The costs of forest haulage after integrated pulpwood and energy wood cutting were higher than those of separate wood harvesting because of lower removals in integrated harvesting. The results showed that when integrated wood harvesting is based on the two-pile cutting method, the removals of both energy wood and pulpwood should be more than 20-25 m³ ha⁻¹ at the integrated harvesting sites in order to achieve economically viable integrated procurement.     

Bioethanol production from grape and sugar beet pomaces by solid-state fermentation

A suitable alternative to replace fossil fuels is the production of bioethanol from agroindustrial waste. Grape pomace is the most abundant residue in San Juan and sugar beet pomace could be important in the region. Solid-State Fermentation (SSF) is a technology that allows transforming agroindustrial waste into many valuable bioproducts, like ethanol. This work reports a laboratory scale SSF to obtain alcohol from grape and sugar beet pomace by means of Saccharomyces cerevisiae yeasts. The initial conditions of the culture medium were: sugars 16.5% (p/p); pH 4.5; humidity 68% (p/p). Cultures were inoculated with 10⁸ cells/g of pomace, and incubated in anaerobic environment, at 28 °C, during 96 h. SSF showed ethanol maximum concentrations at 48 h and ethanol yield on sugars consumed was more than 82%. Yield attained creates expectation about the use of SSF to obtain fuel alcohol.     

Energy and economic analysis of rice production under different farm levels in Guilan province of Iran

The study was carried out on energy requirement and energy input–output relationship of rice production in Guilan province of Iran. Data were collected from 105 farmers with face-to-face questionnaire method. The research results revealed rice production consumed a total energy of 39333 MJ ha⁻¹ which fuel energy use was 46% followed by chemical fertilizer (36%), seed (8%) and biocide (6%), respectively. The share of direct, indirect, renewable and non-renewable energies was 49%, 51%, 11% and 89% respectively. The energy use efficiency and energy productivity were found as 1.53, 0.09 kg MJ⁻¹, respectively. The econometric model was developed using Cobb–Douglas type function and results showed that fuel and machinery energy inputs contributed significantly to the yield. The results of sensitivity analysis of the energy inputs showed that the MPP value of fuel was the highest (0.93), followed by machinery (0.23), biocide (0.17) and seed (0.15) energy inputs. Economic analysis indicated that total cost of production was 3156 $ ha⁻¹. Gross and net return were 1642 $ ha⁻¹ and 940 $ ha⁻¹, respectively and the benefit-cost ratio was calculated 1.29. Mainly, large farms (more than 1 ha) had better management and were more successful in energy use and economic performance.     

Analysis of the characteristics of the residues of the wine production chain finalized to their industrial and energy recovery

In Italy 1.5 Tg dry matter of residues are estimated to be produced by the agri-food sector. Approximately 30% of them are represented by residues of wine industry sector: grape marc. Referring to its production, it is possible to evaluate about 10 Mg of grapes from each vineyard hectare that generate, as wine industry residue, 2.7 Mg of grape marc, corresponding to about 19 GJ in terms of energy content. This kind of biomass is heterogenous and composed of stalks, grape skins and seeds. In this paper, in order to investigate the possibility of an energy and industrial utilization, the physical-chemical characteristics of each single component of grape marc are examined. In addition, a mechanical extraction test on the seed was performed to evaluate the vegetable oil production and the characteristics of the cake. Results on grape marc components put in evidence some difference in terms of ash and chemical elements content, which represent, specifically for these materials, the most critical aspects to take into account in combustion heating systems.     

Energy use patterns and econometric models of major greenhouse vegetable productions in Iran

This paper examines the energy use patterns and energy input-output analysis of major greenhouse vegetable productions in Iran. Data from 43 farmers were obtained using a face-to-face questionnaire method. The majority of farmers in the surveyed region were growing cucumber and tomato. Total input energy was found to be 141493.51 and 131634.19 MJ ha⁻¹ for cucumber and tomato productions, respectively. Among input energy sources, diesel fuel and fertilizers contained highest energy with 54.17-49.02% and 21.64-24.01%, respectively. The energy ratio was found to be 0.69 and 1.48 for cucumber and tomato productions, respectively. Econometric model evaluation showed the impact of human labor for cucumber and chemicals for tomato was significant at 1% levels. Sensitivity analysis indicated that the MPP value of energy inputs were between −5.87 and 7.74. RTS (returns to scale) values for cucumber and tomato yields were found to be 1.29 and 0.76; thus, there prevailed an IRS of cucumber for estimated model. The net return was found positive, as 22651.13 and 78125.08 $ ha⁻¹ for cucumber and tomato, respectively. The benefit-cost ratios from cucumber and tomato productions were calculated to be 1.68 and 3.28, respectively. Among the surveyed greenhouses, the result indicated tomato cultivation was more profitable.     

Renewable energy from thermophilic anaerobic digestion of winery residue: Preliminary evidence from batch and continuous lab-scale trials

The winemaking process generates many by-products besides wastewater, mainly grape marcs, grape stalks, and wine lees. Anaerobic digestion is particularly suitable to treat winery waste because of its high content of nutrient-rich organic matter and for its noticeable energetic potential. To date, only results from mesophilic tests have been extensively reported. In this study, potential methane production and kinetic constants were determined by batch trials under thermophilic conditions and compared with mesophilic values already reported in literature. Grape marcs and wine lees appeared to be the most promising substrates with an estimated potential of 0.34 and 0.37 Nm³CH₄/kgVS_fed, respectively, while grape stalks generated only 0.13 Nm³CH₄/kgVS_fed. In order to assess the feasibility of a continuous anaerobic digestion process, a lab-scale semi-continuous reactor was constructed. Because of the consumption of buffer capacity, the biological process was difficult to control. On the other hand, biogas was produced when working with a hydraulic retention time of 40 d and with previously fermented grape marcs; a specific biogas production of 0.29 Nm³/kgVS_fed was observed. The results of the continuous tests were used to calculate the potential energy recovery from grape marcs produced in Italy (808 thousands of tons per year) in terms of heat and electricity; about 245 GWh of heat and 201 GWh of electricity per annum could be generated in Italian scenario.     

Energy wood harvesting productivity of three harvesting methods in first thinning of scots pine (Pinus sylvestris L.)

Energy wood harvesting in young forests presents an economical challenge and has been dependent on subsidies in Finland. Whole-tree harvesting systems have proved to be most productive when carrying out energy wood harvesting in cleanings and early thinnings in young forests. The application of integrated energy wood and pulpwood harvesting is less common.It was hypothesized that multi-tree harvesting (MTH) with the OM-Waratah 745 single grip harvester head could change harvesting logistics and improve productivity for integrated energy wood and pulpwood thinnings. Two variations of MTH were compared with single-tree harvesting (STH). The logging methods studied were: (1) conventional single-tree harvesting with pulpwood and energy wood processed at the strip road; (2) multi-tree harvesting with pulpwood and energy wood processing along the strip road (MTH1); and (3) multi-tree harvesting at the stump where the aim was to leave the logging residues distributed evenly over the harvesting area and not on the strip roads (MTH2).MTH methods were 28-35% more productive than the single-tree harvesting. The biggest differences in work stages were found in the felling and delimbing stages. In single-tree harvesting felling was 9-26% and delimbing 14-27% slower than in multi-tree harvesting.MTH2 distributed 13% of residues further than 7 m from the strip road center. With STH and MTH1 only a good 1.2-1.7% was placed this far, and 74.4 and 62.0% respectively within 3 m.     

Energy,water and food security through a waste-driven polygeneration system for sustainable dairy production

Ensuring secure and sustainable food production amidst growing demand requires developing high-yield sustainable food production systems, noting that conventional food production systems are large consumers of energy and water resources. Moreover, they induce substantial environmental impacts. In this context, this study considers dairy food production systems, and proposes a dairy waste driven polygeneration system that can increase the milk yield of the dairy food production system whilst reducing its environmental impact. The system utilises dairy manure, very low concentration methane, wastewater, and harsh environmental conditions in an integrated manner to fulfil the dairy farms' vital needs, including air-conditioning, electricity, and freshwater. In addition, the system also provides a solution concerning social perception related to wastewater reuse for potable purposes in the form of an integrated electrolyser and fuel-cell cycle. Unique to this study is the harnessing of the energy of the methane, which is in very low concentrations in the barns, and benefitting from the harsh environmental conditions in an integrated manner. Comprehensive thermodynamic investigations revealed that the system generates 2.17 MW of Electricity, 1152 m³ of freshwater daily, 6970 tons of cooling capacity, and 1.6 kg/day of H₂. Besides, on a daily basis, the system consumes 864 tons of manure, recycles 732.5 m³ of wastewater, and utilises 87.62 tons of methane (resulting in savings of ～711,750 tons of CO₂ eq. annually). The calculated energy and exergy efficiencies of the polygeneration system are 50% and 4%, respectively. Moreover, in the design of polygeneration systems, the importance of the proper definition of the thermodynamic system's boundaries and the effects of technology choice for the same purpose is illustrated. Furthermore, the parametric investigations revealed that the system performs stable with variations in the inputs and ambient conditions. Also, unlike other systems, the system's performance improves in harsher environmental conditions. This study also illustrates that the food production systems can be developed for decentralised operations with near zero-waste outputs and near-zero emissions.     

A comparative study on energy use and cost analysis of potato production under different farming technologies in Hamadan province of Iran

The aim of this study was to determine the amount of input–output energy used in potato production and to make an economic analysis of potato production in Hamadan province, Iran. Data for the production of potatoes were collected from 100 producers by using a face to face questionnaire method. The population investigated was divided into two groups. Group I was consisted of 68 farmers (owner of machinery and high level of farming technology) and Group II of 32 farmers (non-owner of machinery and low level of farming technology). The results revealed that 153071.40 MJ ha⁻¹ energy consumed by Group I and 157151.12 MJ ha⁻¹ energy consumed by Group II. The energy ratio, energy productivity, specific energy, net energy gain and energy intensiveness were calculated. The net energy of potato production in Group I and Group II was 4110.95 MJ ha⁻¹ and −21744.67 MJ ha⁻¹, respectively. Cost analysis showed that total cost of potato production in Groups I and II were 4784.68 and 4172.64 $ ha⁻¹, respectively. The corresponding, benefit to cost ratio from potato production in the surveyed groups were 1.09 and 0.96, respectively. It was concluded that extension activities are needed to improve the efficiency of energy consumption in potato production.     

Energy inputs and crop yield relationships in greenhouse winter crop tomato production

In this study, energy use patterns and the relationship between energy inputs and yield for single crop (winter) greenhouse tomato production were examined in Antalya province, one of the most important greenhouse centres in Turkey. Data were collected using face-to-face surveys from 85 farms producing winter greenhouse tomatoes. The results indicated that the bulk of energy was consumed in fertilizer (38.22%), electricity (27.09%), manure (17.33%) and diesel-oil (13.65%). Average yield and energy consumption were calculated as 57,905.1 kg/ha and 61,434.5 MJ/ha, respectively. Results also determined an output–input ratio of 0.8 and a respective energy productivity and specific energy of 1.061 MJ/t and 0.94 kg/MJ. In addition, the Cobb Douglas production function was applied to test the relationship among different forms of energy consumption. The findings suggested that single crop tomato producers must optimize their use of indirect energy resources. Single crop producers applied an excess use of chemicals, resulting in an inverse effect on yield as well as imposing risks to natural resources and human health. This research suggested an expansion in energy use training opportunities to greenhouse farmers in the region.     

Energy and CO2 emissions associated with mechanical planters used in biomass plantations

Until now, SRC has been studied from many points of view (economic sustainability, environmental impact, harvesting systems, etc.), but few studies of the actual planting operations have been carried out. The objective of this study was to evaluate the energy input and CO₂ emission were evaluated during very Short Rotation Coppice (vSRC) planting. The analysis was performed considering different planter types and tree species (poplar, willow and black locust).This work showed that the energy input and CO₂ emission of vSRC planting is linked to different planter types and, consequently, to the type of planting material used (rods, cuttings and rooting plants). Among the combinations tested, rods planters showed the lowest value for energy consumption (356 MJ ha⁻¹) and CO₂ emission (31 kg ha⁻¹) compared to universal planters type (1028 MJ ha⁻¹ and 92 kg ha⁻¹). No difference between tree species was observed in this experiment. Results highlighted that the energy input required by the planting operation is only 1.7% of the total energy input of the vSRC.