A COMPETITIVIDADE E O GRAU DE CONCENTRAÇÃO DAS EXPORTAÇÕES DO COMPLEXO SOJA DO BRASIL, DA ARGENTINA E DOS ESTADOS UNIDOS DA AMÉRICA NO PERÍODO 1995/2010
This paper analyzes the export competitiveness of soybean in Brazil, Argentina and the United States and the degree of concentration in the main export markets of these countries in the period 1995/2010, using both the index of Revealed Comparative Advantage (RCA) and Concentration ratio (CR). The results reveal, based on the CR3 , that Argentina and Brazil show an increase in the concentration ratio of even crushed soybeans and crude soybean oil, while the US in even crushed soybeans and fractionated soybean oil even. The RCA index shows advantages for all products/countries in both years, except the soy flour to Brazil and Argentina that had values below one. For the US the indexes were lower when compared to the other countries, although it remained as the main exporter of soy flour, fractionated soybean oil even and even crushed soybeans.
Evolução das vantagens comparativas do Brasil no comércio mundial de soja
O objetivo deste trabalho e analisar a evolucao das vantagens comparativas do Brasil nos segmentos de soja em grao, farelo e oleo, no periodo de 1990 a 2002, tendo em vista o conjunto de politicas adotadas na agricultura brasileira nesse periodo. Especificamente, pretendese quantificar e comparar as vantagens comparativas de Brasil, Argentina, EUA e resto do mundo, no comercio mundial de soja. A teoria de vantagem comparativa revelada (VCR) foi utilizada, permitindo computar indices de VCR para o Brasil, Argentina, EUA e resto do mundo nos segmentos de grao, farelo e oleo. Esses indicadores mostraram que o Brasil nao tinha vantagem comparativa 
no segmento de soja em grao, adquirindo vantagens a partir de 1998. Ja no segmento de farelo de soja, as vantagens comparativas do Brasil tem sido reduzidas, destarte o Brasil sempre deteve vantagens comparativas nesse segmento. No segmento de oleo de soja, o Brasil nao apresentou 
vantagens comparativas. Identificou que a Lei Kandir teve um impacto positivo sobre as exportacoes de soja em grao e negativos sobre as exportacoes de farelo e oleo de soja. Ademais, politicas como Moderfrota podem alterar as vantagens comparativas do Brasil, em razao da reducao dos 
custos unitarios de producao via aumentos de produtividade.
Spatial distribution of root lesion nematodes (Pratylenchus spp.) in a long-term no-till cropping system and their relationship with soil and landscape properties
The Cook Agronomy Farm of Washington State University is a long-term precision agriculture study site. Since 2000, the farm has been in various three-year no-till rotations with winter wheat, spring wheat, and various rotation crops such as barley, canola, peas, lentils, and chickpea. The spatial distribution of root lesion nematodes (Pratylenchus spp.) and their relationships with soil and terrain variables were studied by collecting soil samples at 127 and 124 geo-referenced points in two 12-ha fields during the spring of 2010 and 2011, respectively. Pratylenchus spp. were detected in more than 85% of the sampled locations in both fields. Nematode densities spatially mapped using ArcGIS software occurred in an aggregated pattern. Previous rotation crops had no effect on the spatial distribution. Classification and regression tree analysis (CART) using soil and terrain variables, and nematode density, explained 61 and 34% of the variability associated with nematode density in 2010 and 2011, respectively. Soil edaphic factors, such as organic matter, were stronger predictors of nematode populations than rotation effects.