Sugarcane Production In Brazil Research Articles

Costs of Agronomic Practices: Profitability at Different Scales of Sugarcane Production in Brazil

The diversity in agronomic practices being used by sugarcane producers in Brazil determines differences in economic performance and cost structure. The purpose of this study is to evaluate the cost of six systems of agronomic practices using fixed or variable rates for soil amendment, fertilizer, and defensive applications and assess the profitability of these systems at three scales of sugarcane production. We then describe the data sample related to the 2019–2020 harvest season and collected from fifty-five sugarcane producers in the central-south region of Brazil. Thereafter, using a quantitative approach, a cost analysis was performed, and the cumulative frequency of the net revenue for the three scales of production (small, medium, and large), was calculated using a Monte Carlo simulation. The cost analysis indicated that fertilizer had the highest cost considering the agronomic practices adopted at the three scales of production analyzed. The cumulative frequency analysis results from the Monte Carlo simulation showed the highest net revenue per hectare for medium sugarcane producers. In addition, the presence of economies of scale was not confirmed because the lowest cost was found in small-scale sugarcane producers and the highest net revenue was obtained by medium-scale sugarcane producers.

Effect of Production Costs on the Price per Ton of Sugarcane: The Case of Brazil

The costs of agricultural inputs added to those of labor represent almost a third of the total cost of Brazilian sugarcane production. This study analyzes the behavior of the price per ton of sugarcane in Brazil, relating it to the main production costs of this cultivation. Twelve price indicators from January 2015 to December 2020 were evaluated. First, the data were adjusted to a multiple linear regression model to identify the significant variables on variation in the price per ton of sugarcane. Then, the Monte Carlo simulation was used to measure the level of certainty of occurrence of these variables, and forecasts were obtained from the adjustment of ARIMA models. The results showed the influence of the costs of diesel oil, two agricultural pesticides, and daily laborers on the price of sugarcane, besides an increasing trend of its, providing relevant short-term projections for decision-making about investments in the agribusiness sector.

An overview of the sugarcane expansion in the state of São Paulo (Brazil) over the last two decades and its environmental impacts

The state of São Paulo is the leader in the sugarcane production in Brazil. However, the expansion of this culture has been associated with environmental impacts. In this scenario, the determination of growth vectors contributes to establishing areas of higher vulnerability and risks. This research assesses the development of sugarcane cultivation in the state of São Paulo between 1999 and 2019 from an environmental point of view, reviewing its environmental impacts associated with processing. Maps generated compiled information from different Brazilian databases, and the SWOT matrix (strengths, weaknesses, opportunities, and threats) was considered for the areas. The state's land use maps showed the pasture conversion, with a 53.5% reduction in pasture areas and a 143.8% increase in sugarcane cultivation. Sugarcane cultivation and mills are located mainly in the Northwest and West of the state of São Paulo, especially in the administrative regions of São José do Rio Preto, Barretos, Franca, and Ribeirão Preto, which agrees with the state's Agro-environmental Zoning that guides agricultural land use. Such areas are the most susceptible to the immediate environmental impacts of sugarcane cultivation and processing in sugarcane mills and should be priorities for environmental management. The SWOT matrix highlighted the potential for sugarcane production in the state, considering the perspectives to overcome most weaknesses and threats. However, better land-use practices should be applied to sugarcane crops towards outweighing their limitations.

A scalable method for the estimation of spatial disaggregation models

Gaining information about detailed processes using aggregation information is a frequent challenge in research involving geospatial data, with examples in different fields of knowledge such as agronomy, soil science, meteorology, public health, epidemiology, and others. Analyses using aggregated data lead to distorted conclusions since they disregard local patterns, and such a problem has motivated different approaches for reconstructing the information in a finer resolution from the aggregated data. However, most existing methods focus on the particular case where the volume of data does not exceed the amount of memory available for computations, a situation that has become increasingly less frequent with the fast pace of data generation nowadays. In practice, this problem limits either spatial resolution or coverage of applications, thus precluding their use in a more general context. In this paper, we address the problem of disaggregation of spatial data with huge datasets by proposing a scalable method to estimate the parameters of a well-established model. We propose an iterative scheme for model estimation and prove its convergence to a critical point of the likelihood function derived. To test the method, we provide a controlled simulation and a real example for sugarcane production in Brazil. In the simulation, the results indicate a successful reconstruction of 1 million pixels from 90 block areas. In the real example, the results had a compatible match with the agronomic literature, indicating a reasonable prediction of sugarcane production in a 100 m spatial resolution (i.e., approx. 5×108 pixels) from 5,565 block-areas. Compared to the most similar previous work, scalability allowed us to use a nearly 100 times higher resolution, which corresponds to 10,000 times more pixels. With our methods, we expect to assist researchers from different fields in disaggregating spatial information to larger areas or higher resolutions.

Soil tillage and machinery traffic influence soil water availability and air fluxes in sugarcane fields

Intensive soil disturbance by conventional tillage and heavy machinery traffic for planting, cultivation, and harvesting operations are the main causes of soil compaction and degradation of soil physical quality in sugarcane fields. However, the adoption of conservation soil tillage practices, such as no-till and reduced tillage associated with traffic control have been proposed as a key strategy to preserve soil physical quality, enhancing water availability and air fluxes. Nevertheless, the effects of reduced tillage associated with traffic control in sugarcane fields are still not well documented. A study was carried out to quantify soil water availability and air flux indicators in two soils with contrasting textures (named Sandy Loam and Clayey soil) under conventional and reduced tillage practices associated with and without controlled machinery traffic in central-southern Brazil. Soil physical parameters such as bulk density, total porosity, air-filled porosity, air permeability, pore continuity index, and the least limiting water range (LLWR) were measured. In both soils, there was no difference between conventional and reduced tillage in bulk density, air permeability, and LLWR. However, reduced tillage with non-traffic decreased bulk density and increased macroporosity, air-filled porosity, air permeability, pore continuity, and LLWR in Sandy Loam soil. In Clayey soil, the bulk density and LLWR did not change between tillage practices, but air permeability and pore continuity index were larger under reduced tillage with non-traffic. These results highlighted that soil disturbance by conventional tillage does not improve the water availability and air permeability during the crop cycle. However, the traffic control is essential to support the adoption of reduced tillage in sugarcane fields, preserving soil water availability and air fluxes for the subsequent ratoons. Reduced tillage and traffic control are two of the most important pillars for reducing soil compaction and promoting sustainability of sugarcane production in Brazil.

Digital soil mapping outputs on soil classification and sugarcane production in Brazil

Soil maps at regional and farm levels are vital for the best management agricultural practices (BMAP). The soil is the substrate for plant growth and essential to ensure food security. In this context, soil maps require a detailed cartographic scale for BMAP. This study (i) investigated the use of digital soil mapping (DSM) products, such as soil chemical and physical attributes, indices, mineralogy, and properties to extrapolate late soil survey maps at 1:20,000 scale; (ii) created the digital yield environment for sugarcane based on the DSM products; and (iii) evaluated qualitatively the predict soil maps and relationship with previous studies and the predicted yield environment. The region of interest covers eight municipalities and almost 2598 km2 in São Paulo State, Brazil. The soil survey at farm level conducted covered almost 86.52 km2, ∼3.33% of the total area (96.67% of the unmapped area). We created a point grid (centroid) with the same spatial resolution (30 m) of the rasters used as covariates for soil mapping unit (SMU) predictions. This grid intended to retrieve the representative soil mapping unit of each geometric polygon. It was retrieved 117,413 points representing 27 SMU of seven soil orders at a first categorical level, according to the Brazilian Classification System, and seven yield environment for sugarcane production. SMU predictions and their respective soil orders were performed using the random forest machine learning regression method. The level of association between SMU and yield environments was 0.34 (α = 0.01) by the Cramer's V coefficient with a very strong relationship. Our approach could provide the first digital yield environment for sugarcane based on the DSM products. Furthermore, a qualitative evaluation of our framework was substantiated with previous research in the same study site. This framework could be replicated and fulfil the need for DSM at regional and farm levels for policy-makers and farmers.

Utilisation of sugar cane straw ash (SCSA) as pozzolan in partially replacement of Portland cement

Sugarcane production in Brazil considerably increased in the last 10 years. After the mechanized harvesting, it is generated a waste called by sugar cane straw. This straw presents good calorific value and it can be utilised in energy production as a biomass. However, after the energy generation, it is obtained another waste, which does not have a suitable destination, known as the sugar cane straw ash (SCSA). A destination to this material can be as pozzolanic material. Therefore, the SCSA was physically and chemically characterised. The ash presented amorphous silica that can be used in partial replacement of the Portland cement. The ash reactivity was assessed by thermogravimetric analysis (TGA) of lime/pozzolan pastes. Also five replacement percentages of the Portland cement by SCSA in mortars were evaluated: 0 (control), 15, 20, 25 and 30%. Specimens were moulded in order to be assessed by compressive strength after 3, 7, 28 and 90 days of curing at 25 ºC. All mortars presented similar compressive strength after 90 days of curing of approximately 45 MPa. It can be concluded that the SCSA can be used in partial replacement of the Portland cement.

Utilisation of sugar cane straw ash (SCSA) as pozzolan in partially replacement of Portland cement

Sugarcane production in Brazil considerably increased in the last 10 years. After the mechanized harvesting, it is generated a waste called by sugar cane straw. This straw presents good calorific value and it can be utilised in energy production as a biomass. However, after the energy generation, it is obtained another waste, which does not have a suitable destination, known as the sugar cane straw ash (SCSA). A destination to this material can be as pozzolanic material. Therefore, the SCSA was physically and chemically characterised. The ash presented amorphous silica that can be used in partial replacement of the Portland cement. The ash reactivity was assessed by thermogravimetric analysis (TGA) of lime/pozzolan pastes. Also five replacement percentages of the Portland cement by SCSA in mortars were evaluated: 0 (control), 15, 20, 25 and 30%. Specimens were moulded in order to be assessed by compressive strength after 3, 7, 28 and 90 days of curing at 25 ºC. All mortars presented similar compressive strength after 90 days of curing of approximately 45 MPa. It can be concluded that the SCSA can be used in partial replacement of the Portland cement.

Machinery traffic in sugarcane straw removal operation: Stress transmitted and soil compaction

Straw removal requires a complex set of mechanized operations, including machines for raking, baling, and transporting the straw, which may intensify soil physical degradation in sugarcane fields. A field experiment was conducted to estimate the stress transmitted caused by a set of machines used for sugarcane straw removal and to quantify the impact of these stresses on soil physical indicators. The treatments consisted of reproducing the field traffic of individual and sequential operations used for straw removal, including raking; raking + baling; and raking + baling + transporting operations. Soil bulk density (BD), soil penetration resistance (SPR), macroporosity (MaP) and microporosity (MiP) at the depths of 2.5, 5, 15, and 30 cm were measured before and after the field operations. Contact area of the tires and stress transmitted into the soil induced by the straw removal operations were simulated by SoilFlex model and then used to assess the magnitude of the changes in soil physical indicators. Results showed that baling operation transmitted the highest stress (∼400 kPa), followed by straw raking and transporting, whose transmitted stress level exceed 300 kPa near the soil surface. The sum of sequential operations (i.e., raking + bale + transporting) showed the highest negative impact on soil physical quality. The magnitude of the changes in soil physical indicators occurred according to initial conditions of BD and transmitted stress. Our results show that operations for straw removal intensify soil compaction, which can be detrimental to sustain soil health and plant growth. Therefore, we advocate that traffic control strategies should be adopted during the straw removal operations to improve soil quality towards greater sustainability of sugarcane production in Brazil.

Climate Efficiency for Sugarcane Production in Brazil and its Application in Agricultural Zoning

Climate efficiency is an index that shows quantitative reduction related to production caused by the drought. Using climate efficiency in zoning agricolas sure is a vanguard in agrometeorology. Therefore, we aimed to simulate the climate efficiency for sugarcane production in Brazil and test its use in agricultural zoning. Mean annual air temperature, total annual precipitation, and climate efficiency were the climatic variables used to define suitable areas for sugarcane cultivation. Potential and actual yield was established using the agroecological zone method. Regions with mean annual temperatures between 28 and 38 °C, annual precipitations between 1000 and 1500 mm year−1, and climate efficiency higher than 0.65 were considered climatically suitable for cultivation. The interpolation and crossing of information allowed obtaining the climatic aptitude zoning of sugarcane production for Brazil. Kriging was used as an interpolation method, using the spherical model, one neighbor, and a 0.25° resolution (27.75 km). The Brazilian states were divided into three major groups, according to sugarcane climate efficiency. The most favorable states for sugarcane production had a mean climate efficiency of 0.92. On the other hand, the states with the lowest climate efficiencies presented values of 0.59. Climatic aptitude zoning shows that 24.45% of the Brazilian territory is climatically suitable for sugarcane cultivation. Mato Grosso do Sul State has favorable climatic aptitude in 98% of its territory. The aptitude of productive losses due to climate efficiency is the lowest from January to April in Brazil. The Midwest and Northeast regions have the lowest climate efficiencies from June to September, thus requiring other alternatives, such as irrigation systems for crop maintenance. The use of climate efficiency to elaborate agricultural zoning allows determining with a high accuracy suitable areas for sugarcane cultivation.

Abiotic Soil Health Indicators that Respond to Sustainable Management Practices in Sugarcane Cultivation

Soil quality (SQ) assessments are fundamental to design more sustainable land uses and management practices. However, SQ is a complex concept and there is not a universal approach to evaluate SQ across different conditions of climate, soil, and cropping system. Large-scale sugarcane production in Brazil is predominantly based on conventional tillage and high mechanization intensity, leading to SQ degradation. Thus through this study, we aim to assess the impact of sustainable management practices, including cover crops and less intensive tillage systems, in relation to the conventional system, using a soil quality index composed of abiotic indicators. Additionally, we developed a decision tree model to predict SQ using a minimum set of variables. The study was conducted in the municipality of Ibitinga, São Paulo, Brazil. The experimental design used was in strips, with four cover crops and three tillage systems. We evaluated three sugarcane cultivation cycles (2015/16, 2016/17, and 2017/18 crops). To calculate the SQ index, we selected five abiotic indicators: macroporosity, potassium content, calcium content, bulk density, and mean weight-diameter of soil aggregates. Based on our SQ index, our findings indicated that the soil quality was driven by the production cycle of sugarcane. Although a reduction of soil quality occurs between the plant cane and first ratoon cane cycles, from the second ratoon cane there is a trend of the gradual restoration of soil quality due to the recovery of both the soil’s physical and chemical attributes. Our study also demonstrated that the cultivation of sunn hemp and millet as cover crops, during the implementation of sugarcane plantation, enhanced soil quality. Due to the advantages provided by the use of these two cover crops, we encourage more detailed and long-term studies, aiming to test the efficiency of intercropping involving sunn hemp and millet during the re-planting of sugarcane.

Spatial Variation in Environmental Impacts of Sugarcane Expansion in Brazil

In the past decades, sugarcane production in Brazil has expanded rapidly to meet increasing ethanol demand. The large majority of this expansion occurred in Sao Paulo state. We used an integrated approach considering location-specific biophysical characteristics to determine the environmental impacts of sugarcane expansion and their spatial variation in Sao Paulo state (2004–2015). The included environmental impacts are greenhouse gas (GHG) emissions, biodiversity, soil erosion, and water quantity. All impacts were integrated into a single environmental performance index to determine trade-offs between impacts. Our results show a strong spatial variation in environmental impacts and trade-offs between them. The magnitude and direction of these impacts are mostly driven by the type of land use change and by the heterogeneity of the biophysical conditions. Areas where expansion of sugar cane has resulted in mostly negative environmental impacts are located in the center and east of the state (related to the change of shrublands, eucalyptus, and forest), while areas where sugar cane expansion has resulted in positive impacts are located in the center-west and north (related to the change of annual crops). Identifying areas with mainly positive and negative impacts enables the development of strategies to mitigate negative effects and enhance positive ones for future sugarcane expansion.

Modelling the aggregate structure of a bulk soil to quantify fragmentation properties and energy demand of soil tillage tools in the formation of seedbeds

Designing tillage tools to promote only the necessary amount of soil fragmentation with minimum power input have great potential to reduce production costs concomitantly with environmental impacts. Thus, it was developed a model using discrete element method (DEM) of a bulk soil that accounts for the mechanical behaviour of soil aggregates and implemented an aggregate size classifier algorithm to quantify aggregate size distribution and the location of particle bond breaks promoted by tillage in different positions of the soil bin. Using this numerical approach, simulations of tillage activities were carried out for two furrow openers for sugar cane planting: a conventional one and a new tool concept with distinct soil fragmentation principle. The calibrated DEM model was able to reproduce the empirical measurements of soil friability and power demand of tillage. Through the model it was possible to quantify the level of soil structural fragmentation caused by tillage, revealing specific details of aggregate breakage promoted by the evaluated tools. The new tool concept showed potential to decrease the power demand by 28.5% at the same time it increases the fractal fragmentation by 10% in comparison to the conventional tool. From these simulations it was estimated that the implementation of the new tool in the Brazilian sugarcane production may reduce fuel consumption by up to 16%.

Impact of Green Cane Harvesting on Pest Management in Sugarcane

Green cane harvesting is a new agricultural practice that provides many benefits to sugar cane production in Brazil by allowing cane straw to remain on the soil surface. However, this system has complicated the management of weeds, pests and diseases. This review will highlight the impact of green cane harvesting on the management of weeds, insect pests, and pathogens in sugar cane production, and cover novel techniques and practices used to manage pests in this production system. Brazil has a unique agroecosystem that includes tropical and subtropical climates and distinct technical challenges relative to other agricultural regions around the world. Sugarcane stands out as an economically important crop in Brazilian agriculture, both in terms of its planting area and the complexity of the production system (e.g., constant changes in planting, cultural practices, and harvest managements). Brazilian sugarcane production in the 2018/2019 season was 620.44 million tons produced over more than 8.5 million hectares distributed mainly in the states of São Paulo, Goiás, and Minas Gerais. Currently, 38% of this production is intended to produce sugar and 62% to ethanol, generating 29.04 million tons of sugar and 33.14 billion liters of ethanol, making Brazil the largest sugar and ethanol producing country in the world. The sugarcane agroindustry continues to expand in Brazil, showing a great capacity to aggregate value to byproducts of ethanol and sugar, such as vinasse (fertilizer), filter cake (fertilizer and soil conditioner), bagasse (raw-material for industries; animal feed; and electrical energy generation), and plant straws (electrical energy generation). The adoption of mechanized harvests without burning has allowed accumulation of sugarcane straw residues over the cropping area (green cane harvesting). Approximately 84% of the sugarcane production area in Brazil follows green cane harvesting practices. This harvesting system has made the management of weeds, pests and diseases even more complex in sugarcane fields than before. Green cane harvesting has made pest and weed management (mainly) more complex. The presence of residues on the soil directly affects the action of pre-emergent herbicides that are most commonly used in sugarcane and increases the incidence of some important pests such as S. levis and M. fimbriolata. Integration of management programs for weeds, pests, and diseases generates economic benefits and control efficacy (broad spectrum action), maximizing their individual efficacy level, reducing the dependence on only one of them and the risk of selection of resistant pest populations. Monitoring, planning, and evaluation of the history of the sugarcane fields are essentials and assist in decision making regarding the method and time of control to be used. The efficiency of this system assists in the maintenance of high yields, health, and longevity for sugarcane fields.

Impact of permanent traffic lanes on the soil physical and mechanical properties in mechanized sugarcane fields with the use of automatic steering

The randomized traffic during all crop cycles in the Brazilian sugarcane production system enhances soil compaction. The use of automatic steering in controlled traffic farming represents an alternative to minimize soil compaction in the sugarcane fields. Our research aimed to evaluate the changes in the soil physical and mechanical properties under permanent traffic lanes, after three years of sugarcane mechanized harvesting, with the use of automatic steering. The experiment was carried out in the municipality of Nova Europa, state of São Paulo, Brazil, in a sugarcane area, under the following treatments: sugarcane planted in a single-row spacing (1.5 m) with conventional traffic, sugarcane planted in a single-row spacing (1.5 m) with automatic steering, and sugarcane planted with double-combined row spacing (1.50 × 0.90 m) and with automatic steering). The bulk density, soil porosity, soil penetration resistance, aggregate stability, and tensile strength of aggregates, were assessed in the inter-row center and seedbed. Soil load-bearing capacity was also included in this study by modeling of preconsolidation pressure at 0–0.1 m and 0.2–0.3 m of depth. After three years of mechanized operations, with controlled traffic using automatic steering, in a sugarcane field, the soil compaction was higher on the inter-row center (i.e. higher bulk density, tensile strength, and preconsolidation pressure and, lower macroporosity) than on the seedbed. The load-bearing capacity allowed to detect the pronounced effect of the machines’ traffic management systems on the soil compaction. The use of automatic steering reduced the load-bearing capacity in the seedbed in relation to the inter-row center, indicating that such management system preserves the soil physical quality in the ratoon region. Moreover, the lowest soil compression index values observed in the inter-row center, using management systems with automatic steering, indicates a lower susceptibility to undergo additional soil compaction.

Pros and Cons of Sugarcane Straw Recovery in São Paulo

Brazilian sugarcane production is converting from the traditional manual slash-and-burn to mechanized green cane harvest. The resulting sugarcane trash is mostly left on the field and plowed under at the end of a growth cycle, but it could also be recovered and used to increase the energy efficiency of ethanol. In this paper, we explore in a simulation study if straw recovery negatively impacts yields, fertilizer use, nutrient cycling, GHG emissions, and erosion; if there is an optimal recovery rate; and if different recovery rates are advisable for different soil types. We also compare the traditional slash-and-burn management to the green cane management system. Our results show that when performing straw recovery, trade-offs between different factors such as up to 1.3 t/ha lower yields or an up to 30 kg/ha higher demand for fertilizer N under low recovery rates, and higher erosion rates under high recovery rates have to be accepted. Most balanced would be a recovery rate of 40–60%, but the rate should also be adapted to soil type, with less recovery e.g. on soils prone to erosion, and to economic considerations. A comparison between green cane harvest without straw recovery and the traditional slash-and-burn method shows lower erosion rates and higher soil organic carbon contents, but also a higher fertilizer consumption due to nitrogen immobilization on areas under green cane management. Due to these trade-offs, one method cannot be unequivocally commended over the other.

Improving phosphorus sustainability of sugarcane production in Brazil.

Phosphorus (P) use in global food and bioenergy production needs to become more efficient and sustainable to reduce environmental impacts and conserve a finite and critical resource (Carpenter & Bennett, Environmental Research Letters, 2011, 6, 014009; Springmann et al., Nature, 2018, 562, 519). Sugarcane is one crop with a large P footprint because production is centered on P‐fixing soils with low P availability (Roy et al., Nature Plants, 2016, 2, 16043; Withers et al., Scientific Reports, 2018, 8, 2537). As global demand for processed sugar and bioethanol continues to increase, we advocate that improving P efficiency could become a key sustainability goal for the sugarcane industry. Here, we applied the 5R global P stewardship framework (Withers et al., Ambio, 2015, 44, 193) to identify more sustainable options to manage P in Brazilian sugarcane production. We show that current inputs of P fertilizer to the current crop area could be reduced by over 305 Gg, or 63%, over the next three decades by reducing unnecessary P fertilizer use, better utilization of recyclable bioresources and redesigning recommendation systems. Adoption of these 5R options would save the sugarcane industry in Brazil 528 US$ million and help safeguard global food and energy security.

Lethal toxicity of the herbicides acetochlor, ametryn, glyphosate and metribuzin to tropical frog larvae.

Despite the high amphibian biodiversity and increasing pesticide use in tropical countries, knowledge on the sensitivity of tropical amphibians to pesticides remains limited. The aim of this study was to evaluate the acute toxicity of the active ingredients of four of the main herbicides used in Brazilian sugarcane production to tadpoles of two tropical frog species: Physalaemus cuvieri and Hypsiboas pardalis. The calculated 96 h-LC50 (median lethal concentration; in mg a.s./L) values for P. cuvieri and H. pardalis were 4.4 and 7.8 (acetochlor); 15 and <10 (ametryn); 115 and 106 (glyphosate); and 85 and 68 (metribuzin), respectively. These toxicity values demonstrated little interspecies variation and the toxicity of the herbicides appeared to be at least partly related with the respective octanol-water coefficient. Published acute toxicity data of fish and amphibians for herbicides were also compiled from the US-EPA ECOTOX database. These data indicated little difference in herbicide sensitivity between tropical amphibians and both non-tropical amphibians and fish. These findings indicate that temperate (fish and amphibian) herbicide toxicity data are also protective for tropical amphibians. Constraints in such extrapolations and indications for future research are discussed.

Robust multi-criteria weighting in comparative LCA and S-LCA: A case study of sugarcane production in Brazil

This article presents a novel multi-criteria decision analysis (MCDA) model for performing robust indicator weighting in Life Cycle Assessment (LCA) and Social Life Cycle Assessment (S-LCA). This model integrates stochastic weights analysis with preference information that utilizes the value judgements of decision makers, benefitting from the diversity of interests and familiarities of decision makers regarding each indicator. The model considers all decision makers on an equal basis but does not assume they have the same importance. The MCDA model was applied to support the evaluation of the overall environmental and social impacts of manual and mechanical sugarcane harvesting in Brazil based on LCA and S-LCA. Brazilian experts were surveyed on the weights of relevant environmental and social indicators. The novel MCDA approach explores all the possible convex combinations of the weights provided by the surveyed group. The results of the MCDA model show that mechanical harvesting compared to manual harvesting had lower environmental life cycle impacts at the end-point level and better social impacts for all these convex combinations. Decision-making based on environmental impacts at the mid-point level is less clear: manual harvesting is more likely (67% of the convex combinations of the weights) to be considered better than mechanical harvesting; but the advantage of mechanical harvesting over manual harvesting can be greater than the reverse (almost twice as large). This article recommends presenting both mid-point and end-point LCIA results for a thoroughly informed decision-making. The MCDA model developed in this article can also be used to support weighting in future comparative LCA or S-LCA studies.

PRODUCTION, TECHNOLOGY AND ADAPTATION TO CLIMATE CHANGES: THE CHALLENGES TO THE SUGARCANE SECTOR IN BRAZIL

Dada a importância econômica, ambiental e energética da cana-de-açúcar para o Brasil, justifica-se a análise de suas condições para resistir à variabilidade climática e ampliar a oferta de matéria-prima para a produção dos produtos derivados da cana-de-açúcar. Desta forma, este trabalho analisa as condições da produção de cana-de-açúcar no Brasil, identificando algumas vulnerabilidades às mudanças climáticas globais e as possibilidades de adaptação. Nesse intuito, considera-se que a sustentabilidade da produção de cana-de-açúcar possui relação com o cultivo das variedades adequadas, assim a metodologia envolveu entrevistas e visitas a instituições de melhoramento de cana-de-açúcar, além de dados secundários de publicações, eventos técnicos e revisão de literatura. Os resultados indicam baixo rendimento da produção de cana e atraso tecnológico das variedades plantadas e cultivadas, falta de conhecimento sobre cenários climáticos e ações escassas que internalizam a adaptação do setor. Na última década, o setor enfrentou dificuldades que apontavam para a necessidade de mudar o padrão tecnológico na produção de cana-de-açúcar e a mudança climática global reforçou essa necessidade. A superação dos desafios setoriais dependerá da articulação direta entre ciência e desenvolvimento e mudanças nas práticas de gestão, inovação no marco regulatório, políticas públicas para ampliação dos investimentos e difusão de tecnologias. A capacidade de adaptação será diretamente influenciada pelos agricultores, que implementarão as principais diretrizes, e pelos mecanismos políticos e institucionais que estimulam a adoção, financiam investimentos, proporcionam treinamento e disseminam as novas tecnologias. Aumentar a produtividade setorial e adaptar-se aos efeitos e riscos climáticos só será possível através de mudanças no padrão de produção, unindo o uso intensivo de tecnologia e inovação às vantagens naturais para o cultivo de cana-de-açúcar que o país possui.