Effects of research and extension on agricultural growth and equity in Brazil.

Studies the effects of investment in research and extension on total agricultural production and on production of individual crops. Some distributional effects are briefly discussed. Due to the lack of data, the first part of the analysis is restricted to the State of Sao Paulo, and the second part covers the entire country.-from Author

The distribution of agricultural land and the question of agrarian reform in Brazil

Agrarian reform has long been an acute issue in Brazil, where the distribution of cultivable land is extremely unequal. The Land Statute adopted by the military in 1964 constituted a genuine reform programme, which, however, was never implemented as the government chose to modernize agriculture and expand cultivated areas. This has prevented the poorest from having access to the land.-from English summary

Composto e vermicomposto de lixo urbano na produção de mudas de oiti (Licania tomentosa (Benth)) para arborização

Compost and vermicompost, produced from organic fraction of municipal solid wastes were studied as components of potting media for Licania tomentosa (oiti) seedlings production. The objective was to achieve data to amplify the utilization of these products, in order to utilize them to ornamental and urban arborization species. Increasing rates of organic fertilizers were used until the total soil substitution from the potting media. There were no fitotoxic effects. Compost or vermicompost caused higher germination index of seeds and higher growth of plants. The study demonstrated that it is possible to utilize these products in other activities beyond aplication in agricultural soil, and it can generate new markets to this kind of organic fertilizer.

Maturity degree of composts from municipal solid wastes evaluated by differential scanning calorimetry

Differential scanning calorimetry (DSC) in association with chemical analysis was applied to assess the maturity reached by the organic fraction of Municipal Solid Wastes (MSW) subjected to composting processes with manual and fixed aeration and sampled at different composting times. Thermograms showed that the difference in the treatments, i.e., the manual aeration and the fixed aeration, had no relevant effect on the stabilization and maturation of OM in the substrates. Common thermal effects observed were: a low temperature endotherm assigned to dehydration and/or loss of peripheral polysaccharides chains; a medium temperature exotherm assigned to loss of peptidic structures, and a high temperature exotherm assigned to oxydation and polycondensation of aromatic nuclei of the molecule. Results obtained suggest that in the experimental conditions used, a shorter time of composting (about 30 d) appears adequate, in order to limit the extended mineralization of OM, whereas a prolonged composting time (up to 132 d) would produce a compost of poor quality with high ash content and low OM content.

Little cicada of sugarcane Mahanarva posticata (Homoptera: Cercopidae). A Brazilian agricultural pest. Morpho-histological study of salivary glands

Little cicadas are homopteran insect pests of sugarcane plantations. As these insects suck out the sap from the leaf parenchyma, they inoculate a toxic saliva that damages the plant vessels, thus promoting the loss of glucose by the affected plant. The morphological and histological analyses of the salivary glands of the little cicada Mahanarva posticata, revealed that these glands are formed by 2 portions: one portion comprises a group of acini and has been denominated as the principal gland; the second portion is filamentous in nature and has been denominated as the accessory gland; it is formed by very long and fine filaments. The acinous portion of the gland can be subdivided into 2 lobes: an anterior lobe formed by 3 lobules (I, II, III), and a posterior lobe formed by lobule IV and the excretory duct. Histologically, the salivary glands showed that the filaments are empty sutructures composed by several internal channels with secretion granules being observed in the cytoplasm of the cells of the secretory filaments. Lobules I and II of the principal gland are characterized by being highly basophilic and for accumulating a large amount of secretion in both the cytoplasm of the cells and inside secretion vesicles. Histochemically, we verified that the secretion produced by these glands is lipidic and protein in nature, with the production of polysaccharides being very low. The differences in stain and appearance of the different regions of the salivary gland lead us to believe that the final glandular product is lipoproteic in nature.

Assessment of anaerobic sewage sludge quality for agricultural application after metal bioleaching

The effects of metal bioleaching on nutrient solubilization, especially nitrogen and phosphorous, from anaerobically-digested sewage sludge were investigated in this work. The assessment of the sanitary quality of the anaerobic sludge after bioleaching was also carried out by enumerating indicator (total coliforms, fecal coliforms, and fecal streptococci) and total heterotrophic bacteria. The experiments of bioleaching were performed using indigenous sulphur-oxidizing bacteria (Thiobacillus spp.) as inoculum and samples of anaerobically-digested sludge. Nitrogen and phosphorous solubilization from sewage sludge was assessed by measuring, respectively, the concentration of Total Kjeldahl Nitrogen, ammonia, nitrate/nitrite, and soluble and total phosphorous before and after the bioleaching assays. At the end of the experiment, after 4 days of incubation (final pH of 1.4), the following metal solubilization yields were obtained: zinc, 91%; nickel, 87%; copper, 79%; lead, 52%; and chromium, 42%. As a result of sludge acidification, the viable counts of selected indicator bacteria were decreased to below the detection limit (4 × 103 cfu 100 ml-1), followed by an increase in the mineral fraction of nitrogen (from 6 to 10%) and in the soluble fraction of phosphorous (from 15 to 30%). Although some loss of sludge nutrients can occur during solid-liquid separation following bioleaching, its beneficial effects as metal removal and reduction of pathogenic bacteria are sufficient to consider the potential of this treatment before sludge disposal onto agricultural fields.

Oil wastes as unconventional substrates for rhamnolipid biosurfactant production by Pseudomonas aeruginosa LBI

Oil wastes were evaluated as alternative low-cost substrates for the production of rhamnolipids by Pseudomonas aeruginosa LBI strain. Wastes obtained from soybean, cottonseed, babassu, palm, and corn oil refinery were tested. The soybean soapstock waste was the best substrate, generating 11.7 g/L of rhamnolipids with a surface tension of 26.9 mN/m, a critical micelle concentration of 51.5 mg/L, and a production yield of 75%. The monorhamnolipid RhaC10C10 predominates when P. aeruginosa LBI was cultivated on hydrophobic substrates, whereas hydrophilic carbon sources form the dirhamnolipid Rha2C10C10 predominantly. © 2005 American Chemical Society and American Institute of Chemical Engineers.

El comercio exterior de productos agropecuarios latinoamericanos = Special study on trade in agricultural commodities in Latin America

Incluye Bibliografía

Inventory and evaluation of natural resources for regional agricultural planning

Includes bibliography

JSEG-based image segmentation in computer vision for agricultural mobile robot navigation

This project aims to apply image processing techniques in computer vision featuring an omnidirectional vision system to agricultural mobile robots (AMR) used for trajectory navigation problems, as well as localization matters. To carry through this task, computational methods based on the JSEG algorithm were used to provide the classification and the characterization of such problems, together with Artificial Neural Networks (ANN) for pattern recognition. Therefore, it was possible to run simulations and carry out analyses of the performance of JSEG image segmentation technique through Matlab/Octave platforms, along with the application of customized Back-propagation algorithm and statistical methods in a Simulink environment. Having the aforementioned procedures been done, it was practicable to classify and also characterize the HSV space color segments, not to mention allow the recognition of patterns in which reasonably accurate results were obtained.

Leaching of Ni and Cu from mine wastes (tailings and slags) using acid solutions and A. ferrooxidans

The objective of this work is to evaluate the acidic and biological leaching of tailings containing Ni/Cu from a flotation and smelting plant. Acidithiobacillus ferrooxidans, strain LR, was used for bioleaching at pH 1.8 and chemical controls were run parallel to that. The acidic leaching was done within 48 hours at pH 0.5 and 1.0. In the slag inoculated flasks the redox potential was high (600 mV), thus indicating oxidative bacterial activity, however, the obtained results after 15 days showed only around 13% Ni and 8% Cu extractions, which were not different to those of the controls. For the flotation tailings bioleaching extractions were approximately 45% for Ni and 16% for Cu while differing figures were obtained for the chemical controls. These were 30% and 12% respectively. Here we could observe that the presence of bacterial activity led to a higher solubility of Ni. Acid leaching of slag showed higher nickel and copper extractions: 56% and 24% respectively at pH 0.5 and 21% and 11% at pH 1.0. However, the acid consumption was 320 and 150 Kg/ton of slag, respectively, both much higher than in bacterial assays. These results indicated that Ni and Cu solubilization from the slag is acid dependent no matter the redox potential or ferric iron concentration of the leaching solution. For flotation tailings, acid treatment showed extractions of 23% for Ni and 16% for copper at pH 0.5 and 22% and 28%, respectively at pH 1.0. The acid consumption was also higher: 220 and 120 Kg/ton, at pH 0.5 and 1.0, respectively. Based on own findings we could observe that acid leaching is found to be more effective for slag, though the acid consumption is much higher, while for the flotation tailings, bacterial leaching seems to be the best alternative. © (2009) Trans Tech Publications.

ANN statistical image recognition method for computer vision in agricultural mobile robot navigation

The main application area in this project, is to deploy image processing and segmentation techniques in computer vision through an omnidirectional vision system to agricultural mobile robots (AMR) used for trajectory navigation problems, as well as localization matters. Thereby, computational methods based on the JSEG algorithm were used to provide the classification and the characterization of such problems, together with Artificial Neural Networks (ANN) for image recognition. Hence, it was possible to run simulations and carry out analyses of the performance of JSEG image segmentation technique through Matlab/Octave computational platforms, along with the application of customized Back-propagation Multilayer Perceptron (MLP) algorithm and statistical methods as structured heuristics methods in a Simulink environment. Having the aforementioned procedures been done, it was practicable to classify and also characterize the HSV space color segments, not to mention allow the recognition of segmented images in which reasonably accurate results were obtained. © 2010 IEEE.

Agricultural incentives, growth and poverty in Latin America and the Caribbean: cross-country evidence for the period 1960-2005. Did trade liberalization increase the incomes of the poorest?

Includes bibliography

Agricultural incentives, growth and poverty in Latin America and the Caribbean

Includes bibliography

Two decades of adjustment and agricultural development in Latin America and the Caribbean

Includes bibliography