Variabilidade espacial de plantas daninhas em dois sistemas de manejo de solo Spatial variability of weeds in two soil management systems

Estudos sobre a distribuição espacial das plantas daninhas são importantes no contexto agronômico e ambiental. O objetivo deste trabalho foi descrever a distribuição espacial de plantas daninhas em dois sistemas de manejo de solo. O estudo foi realizado em um Latossolo Vermelho distroférrico, em Campo Mourão, PR, utilizado em sistema de plantio direto (PD) e preparo convencional do solo (PC). Estabeleceu-se uma malha referenciada em coordenadas x e y, totalizando 128 pontos amostrais. Avaliou-se a biomassa da parte aérea das plantas, a densidade de plantas, a densidade de Commelina benghalensis e a densidade de Bidens pilosa. Os dados foram submetidos à análise exploratória e à análise variográfica. A variabilidade espacial foi estudada através da geoestatística, mediante a análise de semivariogramas, interpolação por krigagem e construção de mapas de isolinhas. O alcance das variáveis biomassa e densidade de B. pilosa é maior no PD que no PC; para a variável densidade de plantas, o alcance é maior no PC. A distribuição espacial descrita por técnicas geoestatísticas, mostra seu potencial no mapeamento de plantas daninhas o que permite estratégias de manejo localizado e o estabelecimento de critérios para experimentos futuros.<br>Studies of spatial distribution of weeds are important in the agronomic and environmental context. The objective of this research was to describe the spatial distribution of weeds in two soil management systems. This study was accomplished in a Distroferric Red Latosol (Oxisol), located in Campo Mourão, Parana State, Brazil, in no-tillage (NT) and conventional tillage of soil (CT). A grid was established in coordinated x and y, with 128 sampling points. The studied variables were biomass of shoot weeds, density of weeds, Commelina benghalensis density and Bidens pilosa density. Exploratory data analysis was used to evaluate distribution of variables as well as to adapt them for the spatial analysis. The spatial variability was studied using geostatistics by analysis of semivariograms, kriging interpolation and constructions of maps. The ranges of biomass and density of Bidens pilosa, were larger in NT than in the CT. For plant density range was larger in the PC. The spatial distribution described by geostatistics allowed weed mapping and its site specific management and the establishment of criteria for future experiments

Theoretical foundations of emerging economy business research

In “Probing Theoretically into Central and Eastern Europe: Transactions, Resources, and Institutions,” we outlined the contributions of research in Central and Eastern Europe (CEE) to theoretical debates in business research. In this retrospective, we reflect upon the evolution of the field over the past decade. With the fading impact of CEE’s distinct shared history, we suggest that CEE best be analyzed as emerging economies, rather than as a distinct geographic entity. Emerging economy business research is converging on common themes and shared theoretical ideas, while identifying critical variations that constrain generalizations among and beyond emerging economies. This research thus highlights the need to develop a better understanding of the boundary conditions of scholarly theories of business knowledge. Over the past decade, the institution-based view has emerged from distinct intellectual traditions in institutional economics, organizational theory, and the analysis of business–government bargaining. Research in these converging lines of theorizing places contextual variations at the center of explanations of business phenomena around the world. We suggest that the institution-based view is evolving toward a paradigm, and offer suggestions on how to advance this research agenda further, in particular by exploring how firms engage with different sets of potentially conflicting institutions at multiple levels and locations