Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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A comprehensive assessment of agriculture in lowlands of south Brazil: characterization and comparison of current and alternative concepts
Theisen, Giovani - \ 2017
Wageningen University. Promotor(en): N.P.R. Anten, co-promotor(en): L. Bastiaans. - Wageningen : Wageningen University - ISBN 9789463436380 - 234
cropping systems - farming systems - crop management - lowland areas - wetlands - pampas - brazil - intensification - sustainability - productivity - indicators - soil management - rice - flooded rice - oryza sativa - maize - zea mays - glycine max - cover crops - livestock - rotation - mixed farming - seedbed preparation - farm machinery - teeltsystemen - bedrijfssystemen - gewasteelt - laaglandgebieden - wetlands - pampa's - brazilië - intensivering - duurzaamheid (sustainability) - productiviteit - indicatoren - bodembeheer - rijst - natte rijst - oryza sativa - maïs - zea mays - glycine max - dekgewassen - vee - rotatie - gemengde landbouw - zaaibedbereiding - landbouwwerktuigen

Agriculture in the lowlands of south Brazil is of strategic importance at the national level, since it supplies around 80% of the rice consumed by the Brazilian population. In Rio Grande do Sul, the southernmost state in Brazil, three million hectares of lowlands are ready for grain-based agriculture. Of this area, about half is fallow, partly used for cattle grazing, and irrigated rice is the predominant crop, cultivated annually on 1.1 million ha. The remaining area is used for soybean and other crops. The predominant cropping system is a combination of irrigated rice and cattle. Over the last decades, rice yields have steadily increased, but this rise in yield level has to a large extent been obtained at the expense of a continuously higher use of external inputs. The recent introduction of soybean in rotation with rice has partially improved the system, but in most areas the situation is becoming incompatible with the modern demands for sustainability. This thesis presents a long-term study (2006-2015) of five cropping systems for lowlands. Next to monocrop rice and two rice-soybean rotations conducted in either conventional or minimum tillage, the experiment contained two novel systems based on large ridges, on which soybean and maize were combined with either cover crops or crop-livestock integration in winter. In these last systems, 8-m-wide ridges were built to avoid flooding, thus allowing for diversification of cash crops and the cultivation of cover crops or pastures in winter time, as well as the use of no-tillage. All systems were evaluated at process-level, including soil preparation, seeding, plant nutrition, pest management, irrigation, harvesting, transport and cattle management, as well as regarding their performance for the different dimensions of sustainability, particularly environment, land productivity, economics, energy-use and labour. Next to system assessment, two additional experiments were conducted for the evaluation of two specific technologies for soil management in these areas. Crop livestock integration on the ridge-based system offered the best balance between food production, environmental impact and economics. This system is well suited to be used in fields that are kept fallow, thereby enlarging the agricultural productivity of the lowlands. The additional experiments revealed that a knife-roller can successfully substitute plough-and-harrow for soil preparation after rice harvest, and that germination of weed seeds can be reduced if crop seeding is conducted at a lower speed or using a no-tillage seeder equipped with an improved cutting mechanism. Overall the results show that by using alternative cropping systems that allow for diversification and new methods of field management it is possible to simultaneously attain a larger agricultural production and improved sustainability in the lowlands.

Diversity of coordination mechanisms to support transactions : farmer - buyer relationships and farmer performance in the Brazilian pork chain
Müller Martins, Franco - \ 2017
Wageningen University. Promotor(en): S.W.F. Omta; J.H. Trienekens. - Wageningen : Wageningen University - ISBN 9789463436366 - 146
supply chain management - pigmeat - pig farmers - farmers - piglets - buying groups - consumers - brazil - south america - ketenmanagement - varkensvlees - varkensboeren - boeren - biggen - inkoopcombinaties - consumenten - brazilië - zuid-amerika

In the last decades consumers preferences have continuously triggered changes in quality regulations and the implementation of various private quality standards. New quality demands also imply new coordination arrangements to support transactions between food companies and their suppliers. To coordinate these transactions, food companies (i.e. buyers) use different types of governance structures (GSs) made up of different coordination mechanisms (CMs). These mechanisms are used to coordinate aspects such prices, quality, and allocation of resources (e.g. services, inputs). The general goal of this thesis is to analyse the complexity behind the GSs used to support transactions in the Brazilian Pork Chain (BPC). Furthermore, this thesis examines how these GSs impact on farmer performance and farmer investment. Brazil is the fourth world producer and exporter of pork. The quality standards and GSs used in this supply chain offer an interesting background to be examined with implications for theory and management. Chapter 1 presents a general introduction depicting the research problem, the research questions and the theoretical framework used in this thesis hich is grounded on Transaction Costs Economics, Supply Chain Management and Networks Theory. Chapter 2 examines, through an exploratory approach, the relationships between quality requirements and CMs. This study allows us to demonstrate that, in the BPC, chain actors use a wide array of CMs to support a non-diverse set of quality requirements. Quality requirements are based on public regulations and on a few specific requirements set by specific customers. The differences in CMs regard aspects such as base prices, criteria for bonuses, control on inputs and processes and resource allocation. Chapter 3 addresses the complexity of CMs embedded in a GS and the use of plural forms of coordination by individual buyers. A framework setting values of CMs on price, volume, quality and resource allocation, was used to demonstrate that a single GS (e.g. a contract) may include CMs on distinct positions within the market-hierarchy continuum. In addition, this framework is used, in four case studies, to support analyses on how and why individual buyers use plural CMs to support similar transactions. The main explanations that were found were the need to handle market fluctuations, the implementation of new and specific quality requirements, to adopt to CMs used by competitors, and to deal with bargaining power of specific groups of farmers. Chapter 4 applies structural equation modelling (SEM) to analyse influences of vertical (buyer-farmer) and horizontal relationships (farmer-farmer) on performance of pig farmers. Data were obtained through a survey questionnaire applied to 269 pig farmers. The results demonstrate that vertical and horizontal relationships improve performance and that horizontal relationships improve information exchange. In addition, the findings suggest that the context in which transactions take place (i.e. spot market, contracting), may affect these relationships. Chapter 5 analyses, based on the farmer survey, influences of buyer support on famer performance and farmer investments. A SEM analysis was applied to 199 farmers that deliver pigs through contracts. The results demonstrate positive influences of buyer support on farmer performance and farmer investment capacity. Chapter 6 provides a general discussion including theoretical, policy and management implications.

Rainfall over the Netherlands & beyond: a remote sensing perspective
Rí́os Gaona, Manual Felipe - \ 2017
Wageningen University. Promotor(en): R. Uijlenhoet, co-promotor(en): A. Overeem; H. Leijnse. - Wageningen : Wageningen University - ISBN 9789463432009 - 124
rain - remote sensing - satellites - estimation - netherlands - brazil - regen - remote sensing - satellieten - schatting - nederland - brazilië

Earthlings like to measure everything (especially now that we are undergoing the era of big-data revolution) maybe because it is such a nice hobby... although a more serious school of thought believes that when measuring our environment we get to understand physics and ourselves.

This thesis explores the uncertainties in rainfall measurements from state-of-the-art technologies like commercial microwave links (CML) and meteorological satellites. Rainfall has been measured by rain gauges since quite some time ago; and by weather radars since the end of WWII. Here we evaluate the performance of gridded-rainfall products for the land surface of the Netherlands. These gridded-rainfall products are CML-rainfall maps produced by the Royal Netherlands Meteorology Institute (KNMI), and the IMERG product developed by Global Precipitation Measurement mission (GPM).

Overall, this thesis shows that CML-rainfall products are very reliable sources with regards to rainfall estimates for the land surface of the Netherlands... even better than the satellite products for rainfall estimation. We are also confident in the promising potential these technologies hold for places around the world where conventional technologies like gauges or radars are not scarce or not affordable.

Sustainability performance of soybean and beef chains in Latin America
Pashaei Kamali, F. - \ 2015
Wageningen University. Promotor(en): Alfons Oude Lansink; Imke de Boer, co-promotor(en): Miranda Meuwissen. - Wageningen : Wageningen University - ISBN 9789462576087 - 219
bedrijfseconomie - rundvleesproductie - sojabonen - economische productie - agro-industriële ketens - veehouderijbedrijven - economie van de veehouderij - brazilië - latijns-amerika - business economics - beef production - soyabeans - economic production - agro-industrial chains - livestock enterprises - livestock economics - brazil - latin america

Sustainability Performance of Soybean and Beef Chains in Latin America

The objective of this thesis, was to analyze the sustainability performance of soybean and beef production chains in Latin America (LA). First identifying a set of sustainability issues of soybean and beef production chains in a LA-EU context was carried out. Sustainability issues were found to vary across stakeholders’ interests. Next, the environmental and economic performance of four feeding strategies for beef production in southern Brazil were evaluated. Results showed that improved pasture is a promising system as it results in the best environmental and economic performance. Furthermore, the environmental, economic, and social performance of genetically modified (GM), non-genetically modified (non-GM), and organic soybean production was evaluated by capturing the uncertainty of key parameters. Results revealed that none of these systems performed best for all sustainability issues evaluated. Multi-criteria assessment (MCA) has the capability of giving a single overall score per system by aggregating sustainability scores using relative importance weights provided by stakeholders. The results showed that there is potential to use expert elicitation as an alternative to extensive data rich methods. The simulation results showed a higher variation for the organic soybean production system compared to GM and non-GM.

Assessment of strategies for value chains using an extended Structure-Conduct-Performance (SCP) framework: an application to the honey business in Brazil
Santana De Figueiredo Junior, H. - \ 2015
Wageningen University. Promotor(en): Alfons Oude Lansink, co-promotor(en): Miranda Meuwissen. - Wageningen : Wageningen University - ISBN 9789462575516 - 152
bedrijfseconomie - honing - productie - bedrijven - brazilië - business economics - honey - production - businesses - brazil

Keywords: Strategy evaluation, global networks, supply chains, policy Delphi, conjoint analysis, economic development, competitiveness, beekeeping, interventions, uncertainty, upgrading.

Competition for the end-customer nowadays takes place more among networks of firms than among individual firms. The analysis of competing firms, thus, has to go beyond the limits of each firm to incorporate the analysis of the entire chain(s) in which the firms participate. An approach is lacking to integrate the relations between strategy and structural issues, such as regulations, demand trends and concentration of clients/suppliers, and economic performance in terms of the contribution to local development. The general objective of this research was to make ex-post and ex-ante assessments of strategies for honey value chains in Brazil. The honey chain was chosen because of the importance of honey production and trade to Brazil, which was among the top ten world honey exporters in terms of volume. This thesis extended the Structure-Conduct-Performance (SCP) framework to value chains, identifying categories of structure, conduct and performance for value chain streams (segment of a value chain in a territory) and providing an integrated approach to explore possible interactions among those categories. The empirical applications of this research used this value chain SCP framework and focused on three honey value chain streams, located in the northeast of Brazil, all in top producing areas: two in Ceará State (Limoeiro do Norte and Santana do Cariri) and one in Piauí State (Picos). First, likely successful strategies of those value chain streams to their performance were identified for the 2007-2011 period, in a multi-case study. Then, the contributions of individual strategies of those streams to their performance were quantitatively assessed, also for the 2007-2011 period, using conjoint analysis. Finally, using adaptive conjoint analysis, promising strategies in terms of their contribution to chain competitiveness and local development were identified, under different scenarios. The results of this thesis reveal that the value chain SCP framework allows for ex-ante and ex-post integrated assessments of strategies for a segment of a value chain in a territory. The results also show that the relative importance of strategies to enhance performance of the studied honey value chain streams in Brazil depends on industry structure and varies among performance goals. In addition, the alignment of the value chain stream strategies towards a certain performance goal improves the likelihood of success of the implementation task. Moreover, the most commonly applied upgrading typologies do not cover all the strategy choices to value chain streams.

Challenging the claims on the potential of biochar to mitigate climate change
Francischinelli Rittl, T. - \ 2015
Wageningen University. Promotor(en): Thomas Kuijper; Ellis Hoffland; Bas Arts, co-promotor(en): E.H. Novotny. - Wageningen : Wageningen University - ISBN 9789462573253 - 145
klimaatverandering - mitigatie - biochar - bodem - organische koolstof - vloeistofchromatografie - koolstofvastlegging in de bodem - brazilië - climatic change - mitigation - biochar - soil - organic carbon - liquid chromatography - soil carbon sequestration - brazil


In this PhD thesis I studied the influence of biochar discourses on the political practices in Brazil and the impact of biochar on soil organic carbon (SOC) stocks, thus contributing to the current debate on the potential of biochar to mitigate climate change. Biochar is the solid material obtained from the carbonization of biomass. The deliberate production and application to soil distinguishes biochar from other carbonized products, e.g. charcoal. Inspired by the aged charcoal found in the fertile Amazonian Dark Earth (ADE; also known as Terra Preta de Índio), the current application of biochar in soil is claimed to simultaneously address four global challenges: food production, climate change, energy supply and waste reduction (Chapter 1). Biochar is supposed to be an absorbent and stable material, which can be used to retain nutrients in the soil, increasing agricultural productivity, while sequestering carbon over extended periods of time. Therefore, biochar is claimed to be a means to mitigate global climate change. Furthermore, if biochar is produced in a modern pyrolysis plant, it also can co-produce bio-oil and syngas that could be used as energy. And if biochar is produced by carbonization of agricultural residue, biochar may reduce the quantity of solid waste that needs to be disposed of.

In Chapter 2, I analysed the policy arrangement related to biochar along the four dimensions of the policy arrangement approach, which are actors, discourse, power and rules. I focused on Brazil, which is an important player in the international biochar debate. My analysis shows that scientists in research institutions are the dominant players in the network, while policymakers, businessmen and farmers are marginally positioned. Experts from Embrapa occupy central positions and thus exercise most power in the network. Moreover, experts linked to ADE have lost prominence in the network. The cause for this reduction was the shift from the ADE/biochar to the biochar/technology discourse. The latter discourse includes different coalitions, such as: ‘climate change mitigation’, ‘improvement of soil fertility’ and ‘improving crop residue management’. Although the biochar/climate coalition is dominant at international level, it is far less prominent in Brazil. Nationally the discourses of ‘improvement of soil fertility’ and ‘improving crop residue management’ have particularly prompted actors’ relationships and practices. However, the biochar/technology discourse is not (yet) institutionalized into formal rules in Brazil.

As a consequence, the country lacks an established biochar policy field. Brazilian biochar practices focus on the carbonization of the available residues into biochar and on the application of biochar in soils to increase the SOC content and consequently the fertility of these soils. In this context, in Chapter 3 I tested in the field the potential of biochar produced in traditional kilns to increase the C contents of sandy savannah soils. My results show that biochar produced in traditional kilns is less thermally altered than that produced by industrial kilns and therefore rapidly decomposes. The decomposition rate of traditionally produced biochar was higher (decomposition constant k = 0.32-1.00 year-1) than generally assumed (k = 0.0005-0.005 year-1), and higher than the decomposition of native SOC (k = 0.22 year-1). In Chapter 4 I demonstrated in a short-term laboratory experiment that oilseed-derived biochar had a similar or higher decomposition rate than native SOC. My results show that all three tested oilseed biochars decelerate the decomposition of SOC in the biochar-amended soils, with biochar richer in aromatics having a stronger negative effect than biochar richer in aliphatics. Therefore, oilseed biochar directly increases soil C stocks and indirectly raises soil C sequestration in the short term through decreasing the decomposition of native SOC.

In my research, the decomposition studies were performed using 13C isotope analysis. However, the 13C isotope analysis cannot be used when the differences of 13C isotope abundance between biochar and soil are not sufficiently large. Therefore, its use can be limited. In Chapter 5, I aimed at improving the benzene polycarboxylic acid (BPCA) method. I re-designed the protocols of the BPCA method and found a better and faster way to quantify and characterize the BPCAs derived from biochar, compared to the previous protocols. The improved method was then successfully tested and implemented in a laboratory in Brazil.

Combining my findings with results of the literature, I conclude (Chapter 6) that there is no evidence that biochar is a reliable way for C sequestration in sandy soils under savannah environments. Biochar decomposition is highly variable, depending on charring conditions, soil and climate: (i) biochar produced by traditional kilns is less thermally degraded than those pyrolysed by industrial kilns; (ii) in sandy soils less biochar accumulates than in clay-silt soils; and (iii) warm-dry conditions raise the decomposition of biochar. These conclusions have a direct consequence for the development of policies on biochar, because we cannot ensure that biochar will sequester the same quantity of C for the same period at different geographical regions.

The role of psychological factors in the adoption of improved natural grassland by Brazilian cattle farmers in Biome Pampa
Rossi Borges, J.A. - \ 2015
Wageningen University. Promotor(en): Alfons Oude Lansink. - Wageningen : Wageningen University - ISBN 9789462573154 - 182
agrarische economie - boeren - graslandbeheer - graslandverbetering - houding van boeren - gedragsveranderingen - attitudes - rundvee - vleesvee - rundvleesproductie - duurzame ontwikkeling - duurzaamheid (sustainability) - pampa's - brazilië - agricultural economics - farmers - grassland management - grassland improvement - farmers' attitudes - behavioural changes - attitudes - cattle - beef cattle - beef production - sustainable development - sustainability - pampas - brazil
The objective of the research was to explore factors determining cattle farmers' intention to adopt improved natural grassland in Brazil. The research was carried out in the state of Rio Grande do Sul, in the south of Brazil.
Public morals in private hands? : a study into the evolving path of farm animal welfare governance
Toschi Maciel, C. - \ 2015
Wageningen University. Promotor(en): Arthur Mol; Bernd van der Meulen, co-promotor(en): Bettina Bock. - Wageningen : Wageningen University - ISBN 9789462572799 - 149
dierenwelzijn - vee - dierhouderij - overheidsbeleid - europese unie - brazilië - governance - nederland - rechtssystemen - animal welfare - livestock - animal husbandry - government policy - european union - brazil - governance - netherlands - legal systems
Executive summary

The advancement of regulatory instruments providing for farm animal welfare measures has been marked by various political and regulatory constraints in both domestic and international settings.In an attempt to overcome some of these constraints, a number of innovative governance arrangements have been developed over the two last decades, such as the use of private standards.This thesis offers a critical assessment on how and to what extent the policy field of farm animals welfare has been affected by these innovative developments. The assessment provided in this thesis resulted from four independent (but inter-related) studies.

The first study consisted of a theoretical inquiry into the engagement of non-state actors in farm animal welfare policy making in Europe. This study sought to establish the extent to which the changes observed in Europe, specifically in the Netherlands, are consistentwith political modernization theory. This study confirmed that the engagement of non-state actors in farm animal welfare policy-makingin Europe corresponds to themodernization of governance practices, where a new collation of actors, policy discourses and rules come to the fore.

The second study consisted of an empirical investigation ofthe rise of farm animal welfare governance in Brazil. The main objective of this study was to gain insight into a development that remains largely unexplored in the current social science literature, that is, into the factors triggering policy change related to animal protection in developing countries. Data collected through 36 semi-structured interviews amongdifferent groups of Brazilian stakeholders suggested that the main factors leading to the rise of animal welfare governance in Brazil were related to Europe and the World OrganisationforAnimal Health (OIE). The insights gained fromthis exploratory empirical study helped produce an analytical framework for assessing how farm animal welfare measures spread across jurisdictions, which is further elaborated in the third phase of this doctoral research.

Accordingly, in the third study, an empirical and theoretical examination ofanimal welfare governance in the European Union-Brazildyad is performed with the objective of assessing theactors and mechanisms currently in place to advance farm animal welfare in bilateral and international relations. Several initiatives have been identified as useful in coordinating animal welfare measures between theEU and Brazil. The study nonetheless found that initiatives based on policy diffusion mechanisms were the most prominent.

The fourth study entailed a legal analysis ofthe relationship between the regulatory framework of the World Trade Organisation (WTO) and the advancement of animal welfare measures through private standards. The objective of this study was to determine the possibility thatprivate standards fall within the scope of WTO Member States’ obligations listedin Article 13 of the Sanitary and Phytosanitary Agreement (SPS). For that purpose, three fundamental factorsfor claims of breaches of Article 13 to be pursuedwere examined: (i) the applicability of the SPS Agreement to farm animal welfare measures; (ii) the scope of the term ‘non-governmental entities’; and (iii) the existence of factual evidence that a WTO Member has not taken reasonable measures to ensure that SPS disciplines are observed by non-governmental entities or that a WTO Member has encouraged non-governmental entities or have relied upon the services of non-governmental entities that are not SPScompliant. The conclusion drawn from this examination is that convincing legal arguments and factual evidence exist to pursue WTO disputes over the use of private farm animal welfare standards.

Based on all the above findings, the overall assessment of this thesis regarding the evolving path of farm animal welfare governance is four-fold.First, the policy field of farm animal welfare has significantly advanced in and between Europe and Brazil through a variety of non-legislative instruments, such as intergovernmental technical cooperation, capacity building programmes and private standards. Second, the political and regulatory implications of this research regarding the use of private standards in animal welfare indicate that a cautious approach to the use of this policy instrument is required. Third, the policy field of animal welfare has greatly benefited from the entry of the World Organisation for Animal Health (OIE), especially in engaging governments and industries in developing countriesin this area. Finally, a reverse shift (that is, a shift away from private governance and towards public governance) is likely to occur as the path of farm animal welfare policy evolves internationally.

De relatieve duurzaamheid van de Nederlandse roodvleessector: een kwalitatieve vergelijking = A comparative study on the sustainability of the Dutch beef cattle production sector
Bos, A.P. - \ 2015
Wageningen : Wageningen UR Livestock Research (Livestock Research rapport 841) - 68
duurzame veehouderij - vleesvee - vee- en vleesindustrie - nederland - ierse republiek - brazilië - varkenshouderij - pluimveehouderij - internationale vergelijkingen - vergelijkend onderzoek - veehouderij - sustainable animal husbandry - beef cattle - meat and livestock industry - netherlands - irish republic - brazil - pig farming - poultry farming - international comparisons - comparative research - livestock farming
In this study the sustainability of Dutch specialized beef production is compared qualitatively with two other Dutch animal production systems (porc and broilers), and with beef production in Ireland and Brazil, the most prominent exporters of beef to the Dutch market with which the Dutch sector competes. The comparison is done along twelve of the fifteen long-term ambitions of the Dutch governance network ‘Uitvoeringsagenda Duurzame Veehouderij’.
The impact of wood biochar as a soil amendment in aerobic rice systems of the Brazilian Savannah
Carvalho, M.T.M. - \ 2015
Wageningen University. Promotor(en): Holger Meinke, co-promotor(en): Lammert Bastiaans; Pepijn van Oort; A.B. Heinemann. - Wageningen : Wageningen University - ISBN 9789462572522 - 160
houtskool - grondverbeteraars - oryza sativa - rijst - landbouwplantenteelt - bodemvruchtbaarheid - stikstofoxide - savannegronden - brazilië - charcoal - soil amendments - oryza sativa - rice - crop husbandry - soil fertility - nitric oxide - savanna soils - brazil


Keywords: tropical Savannah, biochar, soil fertility, aerobic rice, grain yield, N2O emission

Márcia Thaís de Melo Carvalho (2015). The impact of wood biochar as a soil amendment in aerobic rice systems of the Brazilian Savannah. PhD thesis, Wageningen University, The Netherlands, with summaries in English, Dutch and Portuguese, 160 pp.

Rice is a staple food for 3 billion people in the world. In Brazil, rice is a traditional staple food mostly cultivated by smallholder farmers. Rice is better adapted to soil types and climate conditions of the Brazilian tropical Savannah than crops like corn and soybean. However, environmental and socio-economic constraints such as the variable rainfall and the limited access to mineral fertilization is a challenge for sustainable aerobic rice production in Brazil. Yields can vary from 1 to 5 Mg ha-1. In this context, the use of agronomic techniques able to improve soil properties seems a good option to increase quantity and stability of rice production. The use of biochar as a soil amendment represents one such option. Biochar is carbonized biomass, generally a by-product of bioenergy production from biomass. Its use in agricultural soils is inspired by the very fertile Terra Preta soils, which are a result of pre-Columbian human activity in the Amazon region. A key component of the fertility of Terra Preta soils is the high content of C, mostly present in form of pyrogenic C, result of carbonization of organic material. Pyrogenic C is also an important fraction of the soil organic matter present in the weathered soils of the Brazilian Savannah. These soils are mostly acidic, with low soil organic matter content, requiring liming and mineral fertilization if used for agriculture. The biochar tested in the current research is a by-product of charcoal production from eucalyptus wood via slow pyrolysis at 400-500 ○C. It is a porous material with a high C content and K, Ca and Mg availability, which make it a potentially suitable soil amendment for the low fertile soils of the Brazilian Savannah. We applied biochar in a sandy and a clay soil type of the Brazilian Central West region, where over 40% of the Brazilian total crop production is located. We investigated whether biochar amendment improves soil chemical and physical properties and how this in turn affects aerobic rice yields along four cropping seasons after a single biochar application. In both soil types, biochar decreased soil acidity up to 3.5 years after its application. On the clay soil, biochar application decreased the soil water retention capacity but increased the soil organic matter content. The effect of biochar on rice yields on the clay soil were either absent, negative or dependent on the amount of mineral N applied, as well as biochar-induced changes in soil properties, particularly soil water retention and soil organic matter. Most promising results were observed on the sandy soil, where biochar application increased the soil water retention capacity. On the sandy soil, first two seasons were drier than latter two seasons. Accordingly, effects of biochar on rice yields were divergent: the positive effects observed in the first two seasons were absent in subsequent seasons. During this study, weather conditions and rice blast infestations were factors that influenced the observed effects of biochar on rice yields. Further, biochar did not enhance N2O emissions on the clay soil. Based on these results wood biochar could be considered for use in farming systems of the Brazilian Savannah, particularly on sandy soils.

Wild carnivores (Mammalia) as hosts for ticks (Ixodida) in Panama
Bermudez, S.E. ; Esser, H.J. ; Miranda, R. ; Moreno, R.S. - \ 2015
Systematic and Applied Acarology 20 (2015)1. - ISSN 1362-1971 - p. 13 - 19.
acari ixodidae - brazil - koch - park
This study reports ticks collected from wild carnivores from different habitat types in Panama. We examined 94 individual wild carnivores and we found 87 parasitized by ticks: seven coyotes, six crab-eating foxes, 54 coatis, four raccoons, five ocelots, two pumas, two gray foxes, two skunks, and one each of kinkajou, jaguar, jaguaroundi, greater grison and tayra. We identified 13 species of tick: Ornithodoros puertoricensis, Amblyomma auricularium, A. dissimile, A. mixtum, A. oblongoguttatum, A. ovale, A. parvum, A. pecarium, A. tapirellum, A. varium, Haemaphysalis juxtakochi, Ixodes affinis, Rhipicephalus sanguineus s.l. and immatures of Ixodes and Amblyomma. Amblyomma ovale and A. oblongoguttatum were the most common species, found on nine and six carnivore species respectively. This is the first report of A. oblongoguttatum on Puma yagouaroundi and Procyon lotor; of A. dissimile, A. pecarium, A. tapirellum and A. varium on Nasua narica; and A. auricularium on P. lotor. Our data do not enable us to establish incidence of tick parasitism, but add valuable information to the current knowledge of the tick species that infest wild carnivores in Panama.
Life-history analysis of Thaumastocoris peregrinus in a newly designed mass rearing strategy
Martínez, G. ; López, L. ; Cantero, G. ; González, A. ; Dicke, M. - \ 2014
Bulletin of Insectology 67 (2014)2. - ISSN 1721-8861 - p. 199 - 205.
noackae hymenoptera mymaridae - hemiptera thaumastocoridae - biological-control - invasive pest - 1st record - eucalyptus - heteroptera - brazil
The bronze bug, Thaumastocoris peregrinus Carpintero et Dellape (Heteroptera Thaumastocoridae), is one of the most important emerging pests of Eucalyptus LHeritier plantations worldwide. In the development of strategies to control this pest, establishing effective rearing protocols is fundamental to future research programs. We assessed life-history parameters of the bronze bug in a newly designed mass rearing strategy. Separated units were set up to contain different developmental stages. Egg production by females reared on commonly found Eucalyptus grandis Hill ex Maiden and Eucalyptus tereticornis Smith was evaluated in order to determine which plant species to use in rearing. Females laid more eggs on E. tereticornis than on E. grandis, so the former species was chosen for the rearing. A cohort of 207 eggs was followed in Petri dishes until the last individual died or reached the adult stage. We followed egg production by 15 adult couples from the original cohort. Preparation of 150-200 dishes with hatching eggs per week allows for an average production of 7,500 eggs per week. Under our rearing conditions, eggs started hatching on day six, and the first adults were obtained 23 days after oviposition. Almost half of the eggs did not hatch, and the highest nymphal mortality was recorded in the second instar, while the lowest mortality occurred in the last instar. We discuss the relevance of this mass rearing strategy, both within the context of basic behavioural studies of T. peregrinus, and as a tool for the mass rearing of the biological control agent, Cleruchoides noackae Lin et Huber.
Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns
Sagrilo, E. - \ 2014
Wageningen University. Promotor(en): Thomas Kuijper; Ellis Hoffland. - Wageningen : Wageningen University - ISBN 9789462571679 - 128
organisch bodemmateriaal - grondverbeteraars - koolstofvastlegging in de bodem - vesiculair-arbusculaire mycorrhizae - bodemvruchtbaarheid - glycine max - biochar - stikstoffixatie - kooldioxide - emissie - brazilië - soil organic matter - soil amendments - soil carbon sequestration - vesicular arbuscular mycorrhizas - soil fertility - glycine max - biochar - nitrogen fixation - carbon dioxide - emission - brazil

Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns

Edvaldo Sagrilo


Pyrogenic organic matter (PyOM), also known as biochar, is the product of biomass combustion under low oxygen concentration. There is currently a growing interest in research on the use of PyOM as a soil amendment, inspired by the existence of highly fertile, PyOM-rich anthropogenic soils in the Amazon basin. The presence of PyOM in these so-called Amazonian Dark Earths (ADE) in quantities larger than in the non-anthropogenic surrounding soils is considered one of the main reasons for their high fertility.

Soil additions of PyOM have been suggested to increase soil fertility and crop yields, simultaneously providing additional important environmental services. The offset of CO2 emissions through sequestration of a larger pool of recalcitrant soil organic carbon (SOC) is one of these services. This would at the same time sustain soil microbial activity, which is directly associated to soil quality, for instance, nutrient cycles and plant growth. This multiple win scenario suggests that the addition of PyOM to the soil would be the solution for the “carbon dilemma”. The dilemma states that the main biological benefits from soil organic matter are a consequence of its decay. Therefore, it is unlikely that increased C sequestration and the benefits from its decay can be simultaneously maximized. Rather than win-win, PyOM would then also be subjected to inevitable trade-offs.

Additions of PyOM can modify the turnover rate of native SOC by either accelerating or decelerating its decomposition through a mechanism known as priming. Although positive priming by PyOM has been reported, negative priming has also been found. The higher amount of non-pyrogenic C in ADE, compared to non-anthropogenic surrounding soils has been considered evidence that PyOM can stabilize SOC in the long-term. A complicating issue in studies is that short-term increases in CO2 emission can be due to decomposition of labile PyOM fractions, erroneously suggesting positive priming of SOC. Addition of PyOM can also lead to modifications in the microbial activity and assemblages. Changes in microbial populations can have impacts on their functionality, favouring mutualistic root symbioses such as the arbuscular mycorrhizal fungal (AMF) symbiosis and the rhizobial symbiosis with legumes that is responsible for biological nitrogen fixation (BNF). Although soil amendments with PyOM can stimulate AMF and BNF, results are contrasting and mechanisms are not clear. Most studies of PyOM effects on SOC and on mutualistic root symbioses are from short-term experiments, often conducted in greenhouse or laboratory. Although such studies provide insights in potential factors driving changes in SOC and symbiotic relationships in PyOM-amended soils, they do not assess changes under realistic conditions over periods of time longer that one or a few cropping cycles. Therefore, there is still a gap in our understanding regarding the duration and magnitude of effects over time under field conditions and possible mechanisms involved. This thesis addresses these gaps.

The aim of this research was to provide a better understanding of interactions between PyOM and SOC and the factors controlling symbiotic patterns in a tropical soil amended with PyOM. To reach this aim, I combined greenhouse and field studies. I also used meta-analytic methods in order to quantitatively synthesize data in literature.

In Chapter 2, I combined the results of 46 studies in a meta-analysis. I investigated changes in CO2 emission patterns from an array of PyOM-amended soils and identified the causes of these changes and the possible factors involved. I showed an overall increase of 29% in CO2 emission from PyOM-amended soils. Such increases were only evident in soils amended with a PyOM-C (PyC):SOC ratio >2. These data are consistent with the hypothesis that increased CO2 emission after PyOM addition is additive and mainly derived from PyOM’s labile C fractions rather than from SOC. Therefore, positive priming is not a main driver of increases in CO2 emission in PyOM-amended soils. This PyC:SOC ratio provided the best predictor of increases in CO2 production after PyOM addition to soil. This meta-analysis indicates (i) the importance of taking into account the amount of applied PyC in relation to SOC for designing future decomposition experiments and that (ii) the recalcitrance of PyOM in soil-PyOM mixtures may be less than usually assumed.

A technical problem of separating PyOM-induced priming on SOC from other non-additive interactions is the uncertainty regarding the origin of the respired CO2 (whether from SOC or PyOM). This issue can only be solved with the use of isotopes. In a field study (Chapter 3), I quantified changes in the PyOM and SOC stocks over four soybean cropping cycles (CC) in a sandy Ferralsol, previously supporting a vegetation with C4 plants, amended with different rates of PyOM (0, 5, 10, 20 and 40 Mg ha-1). The PyOM was produced from C3 woody species using traditional pyrolysis methods employed in Northeast Brazil. I used 13C isotopic analysis to discriminate the origin of the C in the soil and quantify the decomposition rates of native SOC and PyOM. I showed that decomposition of traditionally produced PyOM is faster (25-60% within first year) than normally assumed (10-20% within 5-10 years), which was higher than that of native SOC (5-14%). The data indicate preferential decomposition of PyOM compared to native SOC. The intensity of that effect depends on the rate of PyOM applied to the soil. Only on the longer term (>1 yr) addition of PyOM seems to stabilize SOC.

In Chapter 4 I explored mechanisms controlling AMF activity and crop yield in PyOM-amended soils through the use of path analysis. I tested the effects of PyOM rates and P fertilization on soybean root colonization by AMF, soil P and plant performance over four cropping cycles (CCs). Data showed a major effect of CC and P, as well an interaction effect of PyOM x CC on mycorrhizal colonization. There was a linear decrease in root colonization by AMF in CC1 with increasing PyOM rates in contrast to a consistent linear increase in CC4. Plant performance was mainly affected by CC, but a significant interactive effect of PyOM x P was also observed on grain yield. Grain yield was highest at high PyOM rates (20 and 40 Mg ha-1) in the P-fertilized treatments in CC4. Soil pH increased in CC1 with increasing PyOM rates, but no effects were observed in CC4. Path analysis indicated that PyOM effects on root colonization by AMF were not mediated by changes in soil pH or P content. My data are consistent with the hypothesis that interference of PyOM in signalling processes is an important driver of change in AMF activity and that positive effects of PyOM on AMF and crop yield develop with time.

In Chapter 5, I assessed the effects of PyOM application rates and P fertilization on BNF in soybean inoculated with Bradyrhizobium japonicum over four cropping cycles. Again I observed that CC had a significant main effect on most dependent variables, while PyOM was not a significant source of variation. There was a significant PyOM × CC interaction effect on shoot N concentration. In CC1 shoot N concentration after application of 5 Mg PyOM was significantly lower than that of plants grown on plots to which 10 or 20 Mg PyOM was applied. In CC4 shoot N concentration was not affected by PyOM. The major effect of CC was explained through changes in nutrient management, more specifically the addition of micronutrients in CC3 and CC4. Alleviation of micronutrient deficiency increased BNF and also resulted in a positive effect of P on BNF. I conclude that under conditions of adequate management, PyOM application does not improve BNF in soybean.

In Chapter 6 (General Discussion) I synthesize the findings of the previous chapters and use data from additional greenhouse and litterbag field experiments to integrate the results. Data from Chapters 2 and 3 show that if any positive priming occurs due to PyOM addition, it is a small short-term event and does not lead to significant losses of native SOC in the long-term. This was confirmed by data from a 2 yr litterbag experiment, which showed no interaction between decomposition of PyOM and fresh organic matter.

Stability of SOC has been considered an ecosystem property rather than a consequence of recalcitrance, but this definition has not yet been extended to PyOM. In this thesis I demonstrated that stability of PyOM can also be influenced by the soil environment. In order to link PyOM effects to SOC and on root symbioses, I performed path analysis integrating root colonization by AMF, SOC content and Ndfa in one model. We found no significant path coefficients linking AMF and BNF. The model indicated a significant positive path coefficient linking AMF root colonization and SOC in CC4, but not in CC1. The data suggest that PyOM may increase SOC stability through increased AMF activity. Soil aggregation and C sequestration are tightly correlated with abundance of AMF in the soil. I propose that the same mechanism through which AMF stabilizes native SOC may also positively influence PyOM stabilization in the long-term.

In conclusion, I have shown that main beneficial effects of PyOM on AMF and crop yield develop with time, but in well-managed soils increased crop yield is not a direct consequence of increased AMF due to PyOM addition. Finally, although PyOM additions represent an effective form of sequestering C, positive effects of PyOM on crop yield are likely to occur after partial decomposition of PyOM. Therefore, although some benefits of adding PyOM can be simultaneously obtained (C sequestration and increased crop yield), they cannot be simultaneously maximized. This means that the carbon dilemma can only be partially solved by adding PyOM to the soil.

Aquatic risk assessment of pesticides in Latin America
Carriquiriborde, P. ; Mirabella, P. ; Waichman, A. ; Solomon, K. ; Brink, P.J. van den; Maund, S.J. - \ 2014
Integrated Environmental Assessment and Management 10 (2014)4. - ISSN 1551-3793 - p. 539 - 542.
surface waters - south-america - amazon state - brazil - ecosystems - cypermethrin - herbicide - argentina - impact
Latin America is anticipated to be a major growth market for agriculture and production is increasing with use of technologies such as pesticides. Reports of contamination of aquatic ecosystems by pesticides in Latin America have raised concerns about potential for adverse ecological effects. In the registration process of pesticides, all countries require significant data packages on aquatic toxicology and environmental fate. However there are usually no specific requirements to conduct an aquatic risk assessment. To address this issue, the Society of Environmental Toxicology and Chemistry organised a workshop that brought together scientists from academia, government, and industry to review and elaborate on aquatic risk assessment frameworks that can be implemented into regulation of pesticides in Latin America. The workshop concluded that the international framework for risk assessments (protection goals, effects, and exposure assessments, risk characterization and risk mitigation) is broadly applicable in Latin America, but needs further refinement for the use in the region. Some of the challenges associated with these refinements are discussed in the paper. It was recognized that there is potential for data sharing both within and outside of the region where conditions are similar. However there is a need for research to compare local species and environmental conditions to those in other jurisdictions to be able to evaluate the applicability of data used in other countries. Development should also focus on human resources as there is a need to build local capacity and capability, and scientific collaboration and exchange between stakeholders in industry, government, and academia is also important. The meeting also emphasised that, although establishing a regionally relevant risk assessment framework is important, this also needs to be accompanied by enforcement of developed regulations and good management practices to help protect aquatic habitats. Education, training, and communication efforts are needed to achieve this.
Satellite observations indicate substantial spatiotemporal variability in biomass burning NOx emission factors for South America
Castellanos, P. ; Boersma, K.F. ; Werf, G.R. van de - \ 2014
Atmospheric Chemistry and Physics 14 (2014). - ISSN 1680-7316 - p. 3929 - 3943.
ozone monitoring instrument - fire emissions - trace gases - tropospheric chemistry - chemical-composition - nitrogen-dioxide - tropical forest - b experiment - model tm5 - brazil
Biomass burning is an important contributor to global total emissions of NOx (NO+NO2). Generally bottom-up fire emissions models calculate NOx emissions by multiplying fuel consumption estimates with static biome-specific emission factors, defined in units of grams of NO per kilogram of dry matter consumed. Emission factors are a significant source of uncertainty in bottom-up fire emissions modeling because relatively few observations are available to characterize the large spatial and temporal variability of burning conditions. In this paper we use NO2 tropospheric column observations from the Ozone Monitoring Instrument (OMI) from the year 2005 over South America to calculate monthly NOx emission factors for four fire types: deforestation, savanna/grassland, woodland, and agricultural waste burning. In general, the spatial patterns in NOx emission factors calculated in this work are consistent with emission factors derived from in situ measurements from the region but are more variable than published biome-specific global average emission factors widely used in bottom-up fire emissions inventories such as the Global Fire Emissions Database (GFED). Satellite-based NOx emission factors also indicate substantial temporal variability in burning conditions. Overall, we found that deforestation fires have the lowest NOx emission factors, on average 30% lower than the emission factors used in GFED v3. Agricultural fire NOx emission factors were the highest, on average a factor of 1.8 higher than GFED v3 values. For savanna, woodland, and deforestation fires, early dry season NOx emission factors were a factor of ~1.5–2 higher than late dry season emission factors. A minimum in the NOx emission factor seasonal cycle for deforestation fires occurred in August, the time period of severe drought in South America in 2005, supporting the hypothesis that prolonged dry spells may lead to an increase in the contribution of smoldering combustion from large-diameter fuels, offsetting the higher combustion efficiency of dryer fine fuels. We evaluated the OMI-derived NOx emission factors with SCIAMACHY NO2 tropospheric column observations and found improved model performance in regions dominated by fire emissions.
Land use and land cover dynamics in the Brazilian Amazon: understanding human-environmental interactions
Souza Soler, L. de - \ 2014
Wageningen University. Promotor(en): Tom Veldkamp; Peter Verburg, co-promotor(en): Kasper Kok. - Wageningen : Wageningen University - ISBN 9789462570887 - 186
dynamiek van het ruimtegebruik - ontbossing - amazonas - brazilië - remote sensing - land use dynamics - deforestation - amazonas - brazil - remote sensing

Land use and land cover dynamics are a result of the interactions between human activities and the environment. The objective of this thesis is to analyze Amazonian land use and land cover pattern dynamics in order to identify the underlying system dynamics. By combining empirical statistical models and Fuzzy Cognitive Mapping, feedbacks in the human-environment system can be explored to identify more sustainable development pathways. The results show that specific feedback loops can lead to a sustainable human-environment system in the Brazilian Amazon, e.g., in case policies such as Payment for Ecosystems Services (PES) and Reducing Emissions from Deforestation and Forest Degradation (REDD) are enforced. Also, the analysis indicates that land market regulations and the enforcement of the Forestry Code can reduce deforestation. It is concluded that policy effectiveness of sustainable land use practices can be better evaluated by using the combination of statistical and cognitive methods. In summary, the thesis illustrates that added value in analyzing land system changes is achieved if insights obtained at different scales are combined through different methods of analysis.

Antibiotic use in Brazilian broiler and pig production: an indication and forecast of trends
Bokma-Bakker, M.H. ; Bondt, N. ; Neijenhuis, F. ; Mevius, D.J. ; Ruiter, S.J.M. - \ 2014
Lelystad : Wageningen UR Livestock Research (Report / Wageningen UR Livestock Research 714) - 25
pluimvee - pluimveehouderij - varkens - varkenshouderij - antibiotica - dierlijke productie - import - brazilië - poultry - poultry farming - pigs - pig farming - antibiotics - animal production - imports - brazil
To gain insight in antibiotic use in relation to imported products the current use of antibiotics in pork and broiler production in Brazil are identified and trend forecasting of antibiotic use in the coming 3-5 years is performed.
Fusion of MODIS Images Using Kriging With External Drift
Ribeiro Sales, M.H. ; Souza, C.M. ; Kyriakidis, P.C. - \ 2013
IEEE Transactions on Geoscience and Remote Sensing 51 (2013)4. - ISSN 0196-2892 - p. 2250 - 2259.
spatial-resolution - land-cover - wavelet decomposition - prediction - forest - brazil - ihs
The Moderate Resolution Imaging Spectroradiometer (MODIS) has been used in several remote sensing studies, including land, ocean, and atmospheric applications. The advantages of this sensor are its high spectral resolution, with 36 spectral bands; its high revisiting frequency; and its public domain availability. The first seven bands of MODIS are in the visible, near-infrared, and mid-infrared spectral regions of the electromagnetic spectrum which are sensitive to spectral changes due to deforestation, burned areas, and vegetation regrowth, among other land-use changes, making near-real-time forest monitoring a suitable application. However, the different spatial resolution of the spectral bands placed in these spectral regions imposes challenges to combine them in forest monitoring applications. In this paper, we present an algorithm based on geostatistics to downscale five 500-m MODIS pixel bands to match two 250-m pixel bands. We also discuss the advantages and limitations of this method in relation to existing downscaling algorithms. Our proposed method merges the data to the best spatial resolution and better retains the spectral information of the original data.
Decomposition and nutrient release in leaves of Atlantic Rainforest tree species used in agroforestry systems
Duarte, E.M.G. ; Cardoso, I.M. ; Stijnen, T. ; Mendonça, M.A.F.C. ; Coelho, M.S. ; Cantarutti, R.B. ; Kuyper, T.W. ; Villani, E.M.A. ; Mendonça, E.S. - \ 2013
Agroforestry Systems 87 (2013)4. - ISSN 0167-4366 - p. 835 - 847.
n-15 natural-abundance - biological nitrogen-fixation - tropical agroecosystems - plant residues - green manure - minas-gerais - soil - legumes - brazil - biodiversity
Aiming to support the use of native species from the Atlantic Rainforest in local agroforestry systems, we analysed chemical and biochemical components related to leaf decomposition of Inga subnuda, Senna macranthera, Erythrina verna, Luehea grandiflora, Zeyheria tuberculosa, Aegiphila sellowiana, and Persea americana. These tree species are native (except for P. americana) and commonly used in agroforestry systems in the Atlantic Rainforest. For the three first species (Fabaceae), we also analysed the remaining dry matter and released nutrients from leaves, using litter bags, and biological nitrogen fixation, using Bidens pilosa and Brachiariaplantaginea as references of non-N2-fixing plants. Leaves from I. subnuda, L. grandiflora, and P. americana had a lower decomposition rate than the other species, exhibiting negative correlations with lignin/N and (lignin+polyphenol)/N ratios. The percentages of remaining dry matter after 1 year were 69 % (I. subnuda), 26 % (S. macranthera) and 16 % (E. verna). Higher nutrient release was found in decreasing order from residues of E. verna, S. macranthera, and I. subnuda. The percentages of nitrogen fixation were 22.6 % (E. verna), 20.6 % (I. subnuda) and 16.6 % (S. macranthera). Diversification of tree species in agroforestry systems allows for input of diversified organic material and can contribute to maintaining and improving soil functions resulting in improvements of soil quality.
Plankton dynamics under different climate conditions in tropical freshwater systems (a reply to the comment by Sarmento, Amado & Descy, 2013)
Senerpont Domis, L.N. de; Elser, J.J. ; Gsell, A.S. ; Huszar, V.L.M. ; Jeppesen, E. ; Kosten, S. ; Roland, F. ; Sommer, U. ; Donk, E. van; Lurling, M. - \ 2013
Freshwater Biology 58 (2013)10. - ISSN 0046-5070 - p. 2211 - 2213.
amazonian floodplain lake - phytoplankton biomass - highland reservoirs - species composition - northern ethiopia - dry seasons - brazil - community - tigray - time
1.In our recent contribution to the special issue on plankton dynamics in a fast-changing world, we outlined some general predictions of plankton dynamics in different climate regions now and in future, building on the Plankton Ecology Group (PEG) model (de Senerpont Domis et al., 2013). 2.We proposed a stylised version of plankton dynamics in Fig. 3 of our article and stated that these patterns need to be further elaborated. Our figure displays annual plankton dynamics now and in future in oligotrophic, mesotrophic and eutrophic lakes in arctic, temperate and tropical climate zones. 3.We fully agree with Sarmento, Amado & Descy (2013) that more data on tropical regions are needed, and we are looking forward to the emergence of published data from tropical regions to extend our still-limited understanding of plankton dynamics in these regions. 4.Sarmento et al. (2013) did not agree with our predictions on plankton dynamics for hydrology-driven water systems in the tropics. Unfortunately, however, Sarmento et al. (2013) did not substantiate their statements with the much-needed data on plankton dynamics in the tropics. Moreover, they merely provide an overview of precipitation patterns in the tropics, not an alternative hypothesis for our predictions.
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