Biodiesel production from castor oil in Brazil: A difficult reality

The Brazilian National Program for Production and Use of Biodiesel (PNPB in Portuguese) has created a huge demand for biodiesel in Brazil. The PNPB is strongly based on social development through the inclusion of family farmers in projects integrated with biodiesel power plants. Among the various oilseeds, castor bean (Ricinus communis L.) was identified as the ideal one to promote social development in the semi-arid region. However, although promising, the mechanisms of the federal program are still insufficient to promote the effective participation of family farmers. This research shows that companies are facing huge problems in implementing contracts with family farmers. It describes and analyzes the functioning dynamics of this agro-production chain. This paper addresses the identification and the discussion of these obstacles, in order to increase the competitiveness of the biodiesel agribusiness chain, based on castor oil social projects in Brazil.     

Ethanol and food production by family smallholdings in rural Brazil: Economic and socio-environmental analysis of micro distilleries in the State of Rio Grande do Sul

In light of the perspectives of ethanol from sugar cane industry in Brazil and the biofuelscurrent international debate, certain questions ought to be examined. The framework for future expansion of ethanol production, to meet with supply needs at national and international levels using the current production model, does not take into consideration the prospect of Brazil's regional and rural development. Although currently there are no impediments to the culture of sugar cane in Rio Grande do Sul (RS) State, Brazil's largest producer of biodiesel, it imports 98% of its demand for ethanol from São Paulo and other regions. The promotion of ethanol market in that State might pass for a productive model different from the practice in industrial monocultures, given their cultural and agricultural characteristics. The IFES (Integrated Food and Energy System) from COOPERBIO -n Cooperativa Mista de Produção, Industrialização e Comercialização de Biocombustíveis do Brasil Ltda., established on an experimental basis in the State, presents multiple economic, social and environmental benefits, potentializing the present food procuction by smallholders and favoring a sugar cane ethanol greater consumption in the inland of RS State. With a few tweaks and adequate governmental policies and instruments, the expansion of this model may even cover the current demand in the State. In addition to the production of energy and foods less dependent on fossil fuels, this model contributes for preservation of ecosystem services and for climate smart rural sustainable development.     

Photovoltaic energy generation in Brazil – Cost analysis using coal-fired power plants as comparison

We make a brief analysis of the evolution of photovoltaic systems, highlighting the present situation worldwide and in Brazil. We compare costs of energy generation associated to photovoltaic and to coal-fired power plants. Coal-fired generation represents the eligible choice for the Brazilian State of Rio Grande do Sul, where thermal plants may use locally extracted coal. The production cost of the energy generated with coal is evaluated taking in account the effect of the invisible cost represented by externalities that affect human health. The price evolution of Photovoltaic modules is presented, as well as trends on decreasing costs for new installations. We also calculate the production cost of the AC energy generated by three photovoltaic plants, with different power, derived from a model. The model is used to make sensitive analysis based on the adjustment of some factors that directly affect Brazilian costs such as: insolation, module's custom and transportation taxes, effect of economy of scale, cost of money. A cost comparison is made between the two technologies and some government incentives are proposed to narrow the existing financial gap.     

Identification and analysis of local and regional impacts from the introduction of biodiesel production in the state of Piauí

The recent moves towards the insertion of biofuels in the energy matrix of a number of countries are opening new prospects for agricultural production and for agroindustrial chains. The emergence of this new productive base raises new research issues: in what circumstances are the structuring, organization and implementation of these biodiesel productive chains taking place in Brazil? What are the effects of biodiesel production on local economies? Hence, the central objective of this study is identifying their economic and social impacts at the regions where they are installed. The analytical structure was constructed based on theories of regional and spatial economy: location coefficient, shift–share, theories of industrial location. A preliminary analysis identified that a biodiesel productive arrangement is emerging in the State of Piauí, Northeastern Brazil, with the purpose of stimulating regional development using alternative oil-bearing crops. However, the agricultural project in the town of Canto do Buriti/PI has faced problems of both a cultural and productive nature. Preliminary findings reveal productive, organizational, managerial and governance related difficulties and challenges that need to be faced when establishing a new productive base in a location that up to that point lacks a productive tradition.     

Integration of renewable energies using the surplus capacity of wind farms to generate H2 and electricity in Brazil and in the Rio Grande do Sul state: energy planning and avoided emissions within a circular economy

Hydrogen is a clean fuel capable of promoting sustainable energy development. The effective use of surplus energy from wind plants appears as a promising method to produce hydrogen. Accumulating surplus energy through hydrogen production and storage can solve the problem of energy excess, making energy available on-demand. This article explored the potential of hydrogen production from wind energy in three distinct scenarios of surplus energy, and the amount of electricity generation for Brazil and its regions. To a scenario of 6-h of energy excess, the potential for hydrogen production from wind energy was equal to 1.48E + 07 Nm³.d⁻¹. The state of Rio Grande do Sul reached a potential of 1.10E+06 MWh.month-¹ of electricity generation using H₂. Taking into account a payback-time of 3.5 years, the cost of hydrogen production was 0.402 US$.kWh⁻¹. Hydrogen ensures greater energy security in times of energy shortages through biofuel storage. The main goal was to show the possibilities of diversifying the national electrical matrix and the wind resources contribution to the Circular and H₂ Economy in the country.     

Technical note On the development of spatialtemporal solar radiation maps: a Brazilian case study

This work summarizes recently published information on the solar resource of Brazil. We describe the spatial distribution of solar radiation and its relationship with climatic and geographical conditions. In order to harmonize the information in terms of type of instruments, time recording period and data processing methods, a careful selection of records from the data base was made. Density of recording stations is reasonable in the south, southeast and northeast regions of the country, while in the west center and north regions the density of stations is rather poor. The procedure to elaborate the maps of daily solar radiation, monthly and annual average is described. Consideration of the measuring period of the monthly averages, used to elaborate the contour maps, shows that they meet the requirement that 90% of averages are inside the strip of ±7.5%, centralized on the average of very long period measurements. We present one map with the localization of the recording stations and one annual and 12 monthly contour maps, describing daily solar radiation levels over the whole territory. Spacing among the contour lines is (±2 MJm² day). Annual average of solar radiation lies within the interval of ((18±2) MJm² day), except in the northeast region where values higher than (20 MJm² day) are found. Two regions with levels of (16 MJm² day) are also observed. The highest monthly average values (24 MJm² day) are observed in the state of Rio Grande do Sul, southern end of the country, in the summer season (December and January). The lowest values in the country (8 MJm² day) are observed in June and July (winter in the southern hemisphere), on the extreme south coastline of the same state, Rio Grande do Sul, below 32° south latitude.     

Economic feasibility of biodiesel production from Macauba in Brazil

In this work the economic feasibility of biodiesel production in Brazil by using the Macauba oil as raw matter is studied. The software SIMB-E, in which a cash flow model applied to biodiesel production is implemented, was used during simulations. Economic indexes related to biodiesel production features, as well as the competitiveness between selling prices of biodiesel and petrodiesel were considered. It was found that all of the 8 simulated scenarios were potentially profitable, but only 2 of them presented competitive biodiesel selling prices, being considered as worthwhile projects. These were seed-oil plants with alkaline transesterification. Results also indicated that the success of biodiesel production still requires additional revenues beyond that derived from biodiesel itself, including income from the feedstock coproducts and glycerol. Macauba showed to be a potential crop to be used in biodiesel production. However, the domestication and improvement on processing of this species are indispensable to ensure its availability of long-term use.     

Bringing sustainability science to water basin management

Sustainability science studies the causes, pathways and impacts of complex development problems that result from the interaction of natural and social forces. Water availability in arid basins with rapidly growing populations presents a perfect example of a development problem that needs sustainability science to provide the scientific underpinnings for integrated management of the basin. The author (1) introduces the concept of sustainability science, (2) applies the concept to integrated water basin management, and (3) illustrates the use of sustainability science in the management of the arid Rio Grande basin on the border between Mexico and the United States.     

Competitiveness,role, and impact of microalgal biodiesel in the global energy future

This paper examines the competitiveness, role, and impact of microalgal biodiesel in the 21st century using a global energy system model with a detailed technological representation. The major conclusions are the following. First, the competitiveness of microalgal biodiesel decreases as CO₂ stabilization constraints become more stringent. The share of microalgal biodiesel and renewable jet fuel produced from it in total global final energy consumption over the time horizon 2010–2100 is 5.1% in the case without CO₂ constraints compared with 3.9% and 0.7% in the case of CO₂ stabilization at 550 ppmv and 400 ppmv, respectively. This is because production and combustion of microalgal biodiesel release as much CO₂ as is captured from anthropogenic sources and assimilated by microalgae and because CO₂ prices raised by stringent CO₂ stabilization constraints make the economics of microalgal biodiesel unattractive. Second, the competitiveness of microalgal biodiesel is also greatly affected by microalgal production cost and microalgal lipid yield. Under a 400 ppmv CO₂ stabilization constraint, a 50% microalgal production cost decrease leads to increase in total global microalgal biodiesel production over the time horizon by a factor of 6.5, while a 50% microalgal lipid yield increase leads to increase in it by a factor of 4.5. Third, microalgal biodiesel plays an important role in satisfying the energy demand in the transport sector, thereby replacing petroleum products and Fischer–Tropsch synfuels. An increasing proportion of microalgal biodiesel is converted into renewable jet fuel over time to be used as a fuel for aircraft. Fourth, either without CO₂ constraints or under the 550 ppmv CO₂ stabilization constraint, the participation of microalgal biodiesel in the global energy market would have a large impact on the global energy supply and consumption structure. This is not only because of its substitution for other forms of final energy, but also because of the need to satisfy the demand for CO₂ for microalgal production.     

Sustainability of biofuels in Latin America: Risks and opportunities

Several Latin American countries are setting up biofuel programmes to establish alternative markets for agricultural commodities. This is mainly triggered by the current success of Brazilian bioethanol production for the domestic market and for export. Furthermore, the global biofuel market is expected to increase due to ambitious biofuel programmes in the EU and in the USA. Colombia, Venezuela, Costa Rica and Guatemala are focusing on bioethanol production from sugarcane whereas biofuel production in Argentina is based on soy biodiesel. Recent developments of the biofuel sector take place extremely rapid especially in Argentina, which became one of the five largest biodiesel producers in the world in 2008. Till date no specific biofuel sustainability certification systems have been implemented in Latin American, as well as on global level. This fact and the predominant use of food crops for biofuel production raise concerns about the sustainability of biofuel production related to environmental and social aspects. This paper provides an overview of the hotspots of conflicts in biofuel production in Latin America. It investigates presently available sustainability tools and initiatives to ensure sustainable biofuel production in Latin America. Finally, it provides an outlook on how to integrate sustainability in the Latin American biofuel sector.     

Potentialities of energy generation from waste and feedstock produced by the agricultural sector in Brazil: The case of the State of Paraná

The State of Paraná contributes significantly for the Brazilian production of sugar cane, ethanol, soybeans and pigs. In addition to the current production of ethanol, the State has a huge potential for electricity, biodiesel and biogas production. This paper presents an overview of the current situation regarding energy generation from the agricultural sector in the State, an assessment of the potentialities of energy generation from sugar cane residues and pig agricultural chains, as well as an analysis of the socioeconomic factors underlying the availability of feedstock for biodiesel production. This study has shown that it is possible to expand the energy supply in the State using residual biomass from the sugar cane and pig production. On the other side, the biodiesel production increase in the State will depend on the expansion in the consumption of products that use the cake as raw material; the increase in the feedstock availability other than canola, castor beans and sunflower; the increase of the number of family farmers as feedstock providers, so as to ensure access for biodiesel producers to the Social Fuel Stamp.     

Brazilian Biodiesel Policy: Social and environmental considerations of sustainability

The objective of this article is to analyze the Brazilian Biodiesel Policy (PNPB) and to identify the social and environmental aspects of sustainability that are present or absent within it. Biofuels, namely alcohol and biodiesel, have been increasing in popularity on a global scale due to their potential as alternative and renewable energy sources. Brazil, a vast country blessed with abundant natural resources and agricultural land, has emerged as a global leader in the production of biofuels. This article includes a brief analysis of the concept of sustainable development, which served as a basis to evaluate the Policy documents. Although PNPB's implementation, which began in 2004, is still within its initial stage, it was possible to identify and elaborate on the environmental and social aspects of the Policy, namely: the social inclusion of family farmers; regional development; food security; influencing the carbon and energy balance of biodiesel; promoting sustainable agricultural practices and a diversity of feedstock.     

Brazilian biodiesel: The case of the palm's social projects

The Brazilian biodiesel program has created great demand for biodiesel. The production of oleaginous derived biodiesel produced by small-scale farmers is a key objective of PNPB. The Social Fuel Seal is one of the instruments for achieving this goal. Five years after the mandatory implementation of program, Brazil is among the world's leading producers of biodiesel. However, the goal of the productive insertion of small-scale farmers in Brazil's less favored regions has not been fully achieved. The Brazilian government has faced difficulties to promote regional development based on PNPB, consequently not reaching the audacious goals that were set at the beginning of the program. In this context of difficulties, the productive arrangements with palm oil should be emphasized. This paper submits in detail the model developed by Agropalma – in partnership with public agencies – together with family farming in the North of the country. These social projects are taken as reference and can promote social inclusion in the country's national biodiesel productive chain. Moreover, this case can serve as an assessment tool for other countries that seek to invest in the production of biodiesel with the concern for the social production inclusion of disadvantaged small-scale family farmers.     

Greenhouse gas emissions and energy balance of palm oil biofuel

The search for alternatives to fossil fuels is boosting interest in biodiesel production. Among the crops used to produce biodiesel, palm trees stand out due to their high productivity and positive energy balance. This work assesses life cycle emissions and the energy balance of biodiesel production from palm oil in Brazil. The results are compared through a meta-analysis to previous published studies: Wood and Corley (1991) [Wood BJ, Corley RH. The energy balance of oil palm cultivation. In: PORIM intl. palm oil conference – agriculture; 1991.], Malaysia; Yusoff and Hansen (2005) [Yusoff S, Hansen SB. Feasibility study of performing an life cycle assessment on crude palm oil production in Malaysia. International Journal of Life Cycle Assessment 2007;12:50–8], Malaysia; Angarita et al. (2009) [Angarita EE, Lora EE, Costa RE, Torres EA. The energy balance in the palm oil-derived methyl ester (PME) life cycle for the cases in Brazil and Colombia. Renewable Energy 2009;34:2905–13], Colombia; Pleanjai and Gheewala (2009) [Pleanjai S, Gheewala SH. Full chain energy analysis of biodiesel production from palm oil in Thailand. Applied Energy 2009;86:S209–14], Thailand; and Yee et al. (2009) [Yee KF, Tan KT, Abdullah AZ, Lee KT. Life cycle assessment of palm biodiesel: revealing facts and benefits for sustainability. Applied Energy 2009;86:S189–96], Malaysia. In our study, data for the agricultural phase, transport, and energy content of the products and co-products were obtained from previous assessments done in Brazil. The energy intensities and greenhouse gas emission factors were obtained from the Simapro 7.1.8. software and other authors. These factors were applied to the inputs and outputs listed in the selected studies to render them comparable. The energy balance for our study was 1:5.37. In comparison the range for the other studies is between 1:3.40 and 1:7.78. Life cycle emissions determined in our assessment resulted in 1437 kg CO₂e/ha, while our analysis based on the information provided by other authors resulted in 2406 kg CO₂e/ha, on average. The Angarita et al. (2009) [Angarita EE, Lora EE, Costa RE, Torres EA. The energy balance in the palm oil-derived methyl ester (PME) life cycle for the cases in Brazil and Colombia. Renewable Energy 2009;34:2905–13] study does not report emissions. When compared to diesel on a energy basis, avoided emissions due to the use of biodiesel account for 80 g CO₂e/MJ. Thus, avoided life cycle emissions associated with the use of biodiesel yield a net reduction of greenhouse gas emissions. We also assessed the carbon balance between a palm tree plantation, including displaced emissions from diesel, and a natural ecosystem. Considering the carbon balance outcome plus life cycle emissions the payback time for a tropical forest is 39 years. The result published by Gibbs et al. (2008) [Gibbs HK, Johnston M, Foley JA, Holloway T, Monfreda C, Ramankutty N, et al., Carbon payback times for crop-based biofuel expansion in the tropics: the effects of changing yield and technology. Environmental Research Letters 2008;3:10], which ignores life cycle emissions, determined a payback range for biodiesel production between 30 and 120 years.     

Can sunflower provide biofuel for inland demand? An integrated assessment of sustainability at regional scale

Biofuels could reduce reliance on fossil oil, while helping to reduce greenhouse gas emissions and promoting rural development. This study assessed the viability of using local biodiesel production from sunflower in Tuscany (Italy) to meet inland demand for diesel fuel in compliance with the European Directives. A crop growth model, GIS and geostatistics were used to identify suitable areas for biodiesel production, considering potential sunflower yields alongside essential sustainability criteria: energy efficiency and greenhouse gas (GHG) savings throughout the supply chain. Simulation results indicate that biodiesel potential, estimated at 95,000 t/year, corresponds to 104,400 tCO₂ eq/year of GHG saved and to 26,500 TOE/year of fossil energy saved. Two scenarios of biodiesel requirement, derived from EU targets, were evaluated. The results of the evaluation indicated that the 2010 target of replacing 5.75% of transportation diesel fuel can be met, while the 2020 target (reaching a 10% of replacement) cannot be met, since local biodiesel production could replace only 4.78% of diesel fuel requirement. A third scenario considered replacing diesel fuel currently used in the agricultural sector. Results showed that the fuel requirement of this sector cannot be fulfilled since biodiesel could cover only approximately 36% of the expected demand.     

The role of bio-fuels in satisfying US transportation fuel demands

In spite of the abundant interest in conversion of agricultural products into useful energy carriers, there have been relatively few studies assessing the magnitude of the impact these fuels can make on satisfying US energy demands. There have been fewer studies of unintended consequences stemming from these enterprises, although several research groups have begun questioning the appropriate levels of subsidies provided to individuals and companies to stimulate production of bio-fuels. In this paper, the production capacities for bio-fuels—ethanol and biodiesel—are evaluated for their potential impact on the US energy market. Several ramifications of these technologies are reviewed. This study concludes that ethanol or biodiesel production do not appear scalable to make a significant difference on the US fossil fuel demand for transportation. Aspects of this study point to systemic changes that may be required in lifestyles and attitudes toward energy consumption. Finally, comments regarding US energy policies are included to stimulate discussion.     

Large-scale bioenergy production from soybeans and switchgrass in Argentina: Part B. Environmental and socio-economic impacts on a regional level

The feasibility of deploying a socio-economic and environmental impact analysis for large-scale bioenergy production on a regional level is analyzed, based on a set of defined criteria and indicators. The analysis is done for La Pampa province in Argentina. The case study results in conclusions in how far the criteria can be verified ex ante based on available methodologies and data sources. The impacts are analyzed for two bioenergy chains (soybeans and switchgrass) for a set of defined land use scenarios. The carbon stock change for switchgrass ranges from 0.2 to 1.2 ton C/ha/year and for soybean from ?1.2 to 0 ton C/ha/year, depending on the scenario. The GHG emission reduction ranges from 88% to 133% for the switchgrass bioenergy chain (replacing coal or natural gas) and from 16% to 94% for the soybean bioenergy chain (replacing fossil fuel) for various lifetime periods. The annual soil loss, compared to the reference land use system is 2–10 ton/ha for the soybean bioenergy chain and 1–2 ton/ha for the switchgrass bioenergy chain. In total, nine sustainability principles are analyzed. In the case of switchgrass, most environmental benefits can be achieved when produced on suitable land of abandoned cropland. Soybean production for bioenergy shows a good overall sustainability performance if produced on abandoned cropland. The production of switchgrass on degraded grassland shows socio-economic and environmental benefits, which is not the case for soybean production. The production of bioenergy production on non-degraded grassland is not preferred. It is concluded that the scenario approach enables understanding of the complexity of the bioenergy chain and the underlying factors influencing the sustainability principles. It is difficult to give ex ante a final conclusion whether a bioenergy chain is sustainable or not as this depends not only on the previous land use system but also on other factors as the selection of the bioenergy crop, the suitable agroecological zone and the agricultural management system applied. The results also imply that it is possible to steer for a large part the sustainability performance of a bioenergy chain during project development and implementation. Land use planning plays a key role in this process.     

Generation of daily solar irradiation by means of artificial neural net works

The present study proposes the utilization of Artificial Neural Networks (ANN) as an alternative for generating synthetic series of daily solar irradiation. The sequences were generated from the use of daily temporal series of a group of meteorological variables that were measured simultaneously. The data used were measured between the years of 1998 and 2006 in two temperate climate localities of Brazil, Ilha Solteira (São Paulo) and Pelotas (Rio Grande do Sul). The estimates were taken for the months of January, April, July and October, through two models which are distinguished regarding the use or nonuse of measured bright sunshine hours as an input variable. An evaluation of the performance of the 56 months of solar irradiation generated by way of ANN showed that by using the measured bright sunshine hours as an input variable (model 1), the RMSE obtained were less or equal to 23.2% being that of those, although 43 of those months presented RMSE less or equal to 12.3%. In the case of the model that did not use the measured bright sunshine hours but used a daylight length (model 2), RMSE were obtained that varied from 8.5% to 37.5%, although 38 of those months presented RMSE less or equal to 20.0%.A comparison of the monthly series for all of the years, achieved by means of the Kolmogorov–Smirnov test (to a confidence level of 99%), demonstrated that of the 16 series generated by ANN model only two, obtained by model 2 for the months of April and July in Pelotas, presented significant difference in relation to the distributions of the measured series and that all mean deviations obtained were inferior to 0.39 MJ/m².It was also verified that the two ANN models were able to reproduce the principal statistical characteristics of the frequency distributions of the measured series such as: mean, mode, asymmetry and Kurtosis.     

Life cycle assessment of different bioenergy production systems including perennial and annual crops

Energy crops are expected to greatly develop in a very short-term bringing to significant social and environmental benefits. Nevertheless, a significant number of studies report from very positive to negative environmental implications from growing and processing energy crops, thus great uncertainty still remains on this argument. The present study focused on the cradle-to-grave impact assessments of alternative scenarios including annual and perennial energy crops for electricity/heat or first and second generation transport fuels, giving special emphasis to agricultural practices which are frequently surprisingly neglected in Life Cycle Assessment studies despite a not secondary relevance on final outcomes. The results show that cradle-to-farm gate impacts, i.e. including the upstream processes, may account for up to 95% of total impacts, with dominant effects on marine water ecotoxicity. Therefore, by increasing the sustainability of crop management through minimizing agronomic inputs, or with a complementary use of crop resides, can be expected to significantly improve the overall sustainability of bioenergy chains, as well as the competitiveness against fossil counterparts. Once again, perennial crops resulted in substantially higher environmental benefits than annual crops. It is shown that significant amount of emitted CO₂ can be avoided through converting arable lands into perennial grasslands. Besides, due to lack of certain data, soil carbon storage was not included in the calculations, while N₂O emission was considered as omitted variable bias (1% of N-fertilization). Therefore, especially for perennial grasses, CO₂ savings were reasonably higher that those estimated in the present study. For first generation biodiesel, sunflower showed a lower energy-based impacts than rapeseed, while wheat should be preferred over maize for first generation bioethanol given its lower land-based impacts. For second generation biofuels and thermo-chemical energy, switchgrass provided the highest environmental benefits. With regard to bioenergy systems, first generation biodiesel was less impacting than first generation bioethanol; bioelectricity was less impacting than first generation biofuels and second generation bioethanol by thermo-chemical hydrolysis, but highly impacting than Biomass-to-Liquid biodiesel and second generation bioethanol through enzymatic hydrolysis.     

Environmental sustainability and improvement options for agribiomass chains: Straw and turnip rape

Biofuels are seen as an effective means to reduce greenhouse gas (GHG) emissions of energy production. However, the cultivation phase of agribiomass-based biofuel production in particular can cause significant GHG emissions and additional environmental problems, such as water pollution and biodiversity loss. In this study, the aim was to develop a comprehensive environmental sustainability framework for agribiomass chains. The chosen environmental impact categories (climate change, eutrophication, soil erosion, soil organic matter decline, ecotoxicity, biodiversity, use of non-renewable resources, water use, and production efficiency) were selected based on literature and the views of energy companies and interest groups. The framework was tested with two Finnish agribiomass chains: barley (Hordeum vulgare L.) straw (for combustion) and turnip rape (Brassica rapa ssp. oleifera DC.) (for biodiesel). Relevant improvement options were identified and their impact reduction potential was assessed.The GHG emissions of both selected bioenergy sources were less than those of their fossil fuel references. Critical challenges for both studied agribiomass chains currently include eutrophication, soil organic matter decline and the use of non-renewable natural resources. The indicator values could be markedly improved by the selected improvement options, of which the most important is optimal yield. Better distributions of manure and soil fertility improvement (carbon stock and pH) were identified as the most important long-term goals for improving sustainability.