Cropping systems, carbon sequestration and erosion in Brazil, a review

Soils represent a large carbon pool, approximately 1500 Gt, which is equivalent to almost three times the quantity stored in terrestrial biomass and twice the amount stored in the atmosphere. Any modification of land use or land management can induce variations in soil carbon stocks, even in agricultural systems that are perceived to be in a steady state. Tillage practices often induce soil aerobic conditions that are favourable to microbial activity and may lead to a degradation of soil structure. As a result, mineralisation of soil organic matter increases in the long term. The adoption of no-tillage systems and the maintenance of a permanent vegetation cover using Direct seeding Mulch-based Cropping system or DMC, may increase carbon levels in the topsoil. In Brazil, no-tillage practices (mainly DMC), were introduced approximately 30 years ago in the south in the Parana state, primarily as a means of reducing erosion. Subsequently, research has begun to study the management of the crop waste products and their effects on soil fertility, either in terms of phosphorus management, as a means of controlling soil acidity, or determining how manures can be applied in a more localised manner. The spread of no-till in Brazil has involved a large amount of extension work. The area under no-tillage is still increasing in the centre and north of the country and currently occupies ca. 20 million hectares, covering a diversity of environmental conditions, cropping systems and management practices. Most studies of Brazilian soils give rates of carbon storage in the top 40 cm of the soil of 0.4 to 1.7 t C ha(-1) per year, with the highest rates in the Cerrado region. However, caution must be taken when analysing DMC systems in terms of carbon sequestration. Comparisons should include changes in trace gas fluxes and should not be limited to a consideration of carbon storage in the soil alone if the full implications for global warming are to be assessed.

Simulating SOC changes in 11 land use change chronosequences from the Brazilian Amazon with RothC and Century models

Land use and land cover changes in the Brazilian Amazon have major implications for regional and global carbon (C) cycling. Cattle pasture represents the largest single use (about 70%) of this once-forested land in most of the region. The main objective of this study was to evaluate the accuracy of the RothC and Century models at estimating soil organic C (SOC) changes under forest-to-pasture conditions in the Brazilian Amazon. We used data from 11 site-specific 'forest to pasture' chronosequences with the Century Ecosystem Model (Century 4.0) and the Rothamsted C Model (RothC 26.3). The models predicted that forest clearance and conversion to well managed pasture would cause an initial decline in soil C stocks (0-20 cm depth), followed in the majority of cases by a slow rise to levels exceeding those under native forest. One exception to this pattern was a chronosequence in Suia-Missu, which is under degraded pasture. In three other chronosequences the recovery of soil C under pasture appeared to be only to about the same level as under the previous forest. Statistical tests were applied to determine levels of agreement between simulated SOC stocks and observed stocks for all the sites within the 11 chronosequences. The models also provided reasonable estimates (coefficient of correlation = 0.8) of the microbial biomass C in the 0-10 cm soil layer for three chronosequences, when compared with available measured data. The Century model adequately predicted the magnitude and the overall trend in delta C-13 for the six chronosequences where measured 813 C data were available. This study gave independent tests of model performance, as no adjustments were made to the models to generate outputs. Our results suggest that modelling techniques can be successfully used for monitoring soil C stocks and changes, allowing both the identification of current patterns in the soil and the projection of future conditions. Results were used and discussed not only to evaluate soil C dynamics but also to indicate soil C sequestration opportunities for the Brazilian Amazon region. Moreover, modelling studies in these 'forest to pasture' systems have important applications, for example, the calculation of CO, emissions from land use change in national greenhouse gas inventories. (0 2007 Elsevier B.V. All rights reserved.

Predicted soil organic carbon stocks and changes in the Brazilian Amazon between 2000 and 2030

Currently we have little understanding of the impacts of land use change on soil C stocks in the Brazilian Amazon. Such information is needed to determine impacts'6n the global C cycle and the sustainability of agricultural systems that are replacing native forest. The aim of this study was to predict soil carbon stocks and changes in the Brazilian Amazon during the period between 2000 and 2030, using the GEFSOC soil carbon (C) modelling system. In order to do so, we devised current and future land use scenarios for the Brazilian Amazon, taking into account: (i) deforestation, rates from the past three decades, (ii) census data on land use from 1940 to 2000, including the expansion and intensification of agriculture in the region, (iii) available information on management practices, primarily related to well managed pasture versus degraded pasture and conventional systems versus no-tillage systems for soybean (Glycine max) and (iv) FAO predictions on agricultural land use and land use changes for the years 2015 and 2030. The land use scenarios were integrated with spatially explicit soils data (SOTER database), climate, potential natural vegetation and land management units using the recently developed GEFSOC soil C modelling system. Results are presented in map, table and graph form for the entire Brazilian Amazon for the current situation (1990 and 2000) and the future (2015 and 2030). Results include soil organic C (SOC) stocks and SOC stock change rates estimated by three methods: (i) the Century ecosystem model, (ii) the Rothamsted C model and (iii) the intergovernmental panel on climate change (IPCC) method for assessing soil C at regional scale. In addition, we show estimated values of above and belowground biomass for native vegetation, pasture and soybean. The results on regional SOC stocks compare reasonably well with those based on mapping approaches. The GEFSOC system provided a means of efficiently handling complex interactions among biotic-edapho-climatic conditions (> 363,000 combinations) in a very large area (similar to 500 Mha) such as the Brazilian Amazon. All of the methods used showed a decline in SOC stock for the period studied; Century and RothC simulated values for 2030 being about 7% lower than those in 1990. Values from Century and RothC (30,430 and 25,000 Tg for the 0-20 cm layer for the Brazilian Amazon region were higher than those obtained from the IPCC system (23,400 Tg in the 0-30 cm layer). Finally; our results can help understand the major biogeochemical cycles that influence soil fertility and help devise management strategies that enhance the sustainability of these areas and thus slow further deforestation. (C) 2007 Elsevier B.V. All rights reserved.

Effect of pH on the development of acidic sites in clayey and sandy loam Oxisol from the Cerrado Region, Brazil

Titration curves were determined for soil from horizon samples of a clayey and a sandy loam Oxisol by (a) adding NaOH to soil suspensions and (b) incubating moist soils with Ca(OH)(2). The organic fraction was primarily responsible for buffering in both soils. Humic acids were more important than fulvic acids in buffering against NaOH additions. With Ca(OH)(2), greater buffer capacities were found due to carboxyl sites, primarily on fulvic acids, becoming complexed with Ca2+ so that in the clay soil humic and fulvic acids were equally important as buffering components while fulvic acids were more important in the sandy loam soil. The buffer capacity of organic matter against Ca(OH)(2) additions was 1.1 mol(c) kg(-1) pH(-1). In the incubated soils, exchangeable cations were also determined and changes in the amounts of exchangeable and non-exchangeable Ca2+ acidity and effective cation exchange capacity were calculated. Up to half the added Ca2+ became complexed and was nonexchangeable. Aluminum complexed by organic matter appears to be an important buffering component, together with non exchangeable H+. With the increase of pH the dissociated sites from the carboxyl groups could complex Ca2+. (c) 2005 Elsevier B.V. All rights reserved.

Threshold effects in price transmission: The case of Brazilian wheat, maize, and soya prices

Recent studies into price transmission have recognized the important role played by transport and transaction costs. Threshold models are one approach to accommodate such costs. We develop a generalized Threshold Error Correction Model to test for the presence and form of threshold behavior in price transmission that is symmetric around equilibrium. We use monthly wheat, maize, and soya prices from the United States, Argentina, and Brazil to demonstrate this model. Classical estimation of these generalized models can present challenges but Bayesian techniques avoid many of these problems. Evidence for thresholds is found in three of the five commodity price pairs investigated.

The role of food standards in international trade: evidence from Brazilian beef exports to the EU market

The study reviews the literature on global chain governance and food standards to allow for an assessment of Brazilian beef exports to the European Union. The empirical approach employed is based on company case studies. The results suggest that the Brazilian beef chain has little choice but to adapt to market changes as standards evolve. Costs of compliance for meeting international food standards reduce Brazil's comparative advantage. At the same time, changes in the nature of demand have created the need for a more integrated supply chain in order to enhance confidence in Brazil's beef production and processing abroad.

Trust and governance of global value chains: The case of a Brazilian beef processor

Purpose - The purpose of this paper is to offer an exploratory case study comparing one Brazilian beef processor's relationships supplying two different distribution channels, an EU importer and an EU retail chain operating in Brazil. Design/methodology/approach - The paper begins with a short review of global value chains and the recent literature on trust. It gives the background to the Brazilian beef chain and presents data obtained through in-depth interviews, annual reports and direct observation with the Brazilian beef processor, the EU importer and the retailer. The interviews were conducted with individual firms, but the analysis places them in a chain context, identifying the links and relationships between the agents of the chains and aiming to describe each distribution channel. Findings - Executive chain governance exercised by the domestic retailer stimulates technical upgrading and transferring of best practices to local. suppliers. Consequently, this kind of relationship results in more trust within the global value chain. Practical implications - There are difficulties and challenges facing this Brazilian beef processor that are party related to the need to comply with increasingly complex and demanding food safety and food quality standards. There is still a gap between practices adopted for the export market and practices adopted locally. The strategies of transnational retailers in offering differentiated beef should be taken in account. Originality/value - The research outlines an interdisciplinary framework able to explain chain relationships and the kind of trust that emerges in relationships between EU importer/retail and a developing country supplier.

Do all tannins have similar nutritional effects? A comparison of three Brazilian fodder legumes

Three tropical legumes, namely Leucaena leucocephala, Sesbania sesban and Cajanus cajan, were subjected to chemical analysis plus in vitro, in situ and in vivo evaluations. Three different assays were used to determine total tannins: adsorption to polyvinyl pyrrolidine (PVPP-tannins), radial diffusion (RD-tannins) and protein precipitation capacity (BSA-tannins). Total phenols, total tannins and condensed tannins were highest for Sesbania. RD-tannins were correlated with total phenols (r(2) = 0.93), PVPP-tannins (r(2) = 0.92) and condensed tannins (r(2) = 0.99). The protein precipitation capacity of Sesbania, Leucaena and Cajanus were 25.9, 6.13 and 4.05 mu g BSA/g DM, respectively. Gas production at 24h was negatively correlated with total phenols (r(2) = 0.99), PVPP-tannins (r(2) = 0.99) and condensed tannins (r(2) = 0.91). The RD-, PVPP-tannins and the response to polyethylene glycol (PEG) in the gas production assay appeared to be useful as a first screen for tannins. In situ degradability did not reflect any adverse effects of tannins. However, in vivo experiments showed that the apparent DM digestibility of Sesbania and Leucaena was lower than the basal diet. The apparent protein digestibility was lower for all legumes compared to the basal diet. Most treatments caused a negative nitrogen balance. The problems associated with browse feeding were not only related to tannin contents, other factors such as inherently poor digestibility and low energy intake may also have lead to the poor animal performance on these diets. We propose, given the limitations of current tannin assays, that it is not possible to predict beneficial or harmful nutritional effects from total tannin concentrations per se. (C) 2004 Elsevier B.V. All rights reserved.

International construction and Brazilian contractors’ operations

The international construction market is very complex, and requires strong structure and strategy for companies wanting to operate overseas. This article investigates characteristics of international construction. The international operation of Brazilian contractors is explored via results from a qualitative study which was carried out using case studies. The case studies comprised ten big Brazilian contractors, six of which operate abroad. The study identified the patterns of international operation, the competitive advantages of these contractors, as well as the difficulties faced by them in the international construction market. Four of the contractors studied operate only in the domestic market. The study of these cases revealed both obstacles and motivations for future international operations. The study revealed that despite the existing competitive advantages, Brazilian contractors' presence in the international market is limited. The main reason for that is probably their main competitive disadvantage: the lack of financial support from the government.

The new Brazilian cinema

In the second half of the 1990s, Brazil experienced a cinematic boom. Many of the new films were received enthusiastically by audiences and critics and released worldwide. This passionately argued and illuminating book provides the first comprehensive critical account of what is known as the 'Renaissance of Brazilian cinema' and demonstrates just how thought-provoking and inspiring Brazilian cinema has become. Contributors: José Carlos Avellar - Ivana Bentes - Stephanie Dennison - Verônica Ferreira Dias - Carlos Diegues - Amir Labaki - Maria Esther Maciel - José Álvaro Moisés - Laura Mulvey - Lúcia Nagib - Luiz Zanin Oricchio - Fernão Pessoa Ramos - Lisa Shaw - Robert Stam - João Luiz Vieira - Ismail Xavier.

Going global: the Brazilian scripted film

This article departs from the assumption that a certain section of world cinema, usually defined as ‘independent’, has been evolving on the basis of good scripts. Between the late 1980s and early 90s, there has been a boom of new cinemas in the world, such as the new Iranian, Taiwanese, Japanese, Mexican, Argentine and Brazilian cinemas. A significant part of this production shows a renewed interest in local and national peculiarities of their respective countries, going against the grain of globalisation and its typical cultural dilution. Most of these films are also engaged in reassessing narrative cinema, as a kind of reaction against the deconstructive work carried out by postmodern cinema of the 1980s.Recent new cinemas are supported by a combination of local and international resources, derived from public and private sponsors at home, and funding agencies, festivals and TV channels abroad. In most cases funds are granted after the film script has been analysed and approved by commissions of experts. The New Brazilian Cinema, or cinema da retomada as it is locally called, has been enormously affected by this scheme, which has even caused a ‘script boom’ in Brazil in the past decade. The chapter examins the results of this process.