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Objetivou-se com este estudo, avaliar a variabilidade espacial da resistência à penetração de um Latossolo Vermelho distroférrico. O experimento de campo foi instalado na Fazenda Experimental da Universidade Federal da Grande Dourados, em Dourados/MS. Utilizou-se uma área experimental de 5,02 ha e grid amostral de 25 x 25 metros, com pontos georreferenciados por um GPS. A resistência à penetração foi determinada utilizando um penetrógrafo com haste de 60 cm. A umidade do solo na área, no momento da coleta de dados, foi de 18,5% base seca (bs). Os dados foram submetidos à análise geoestatística utilizando o programa GS+ e os mapas foram confeccionados no programa computacional Surfer, versão 8. A camada compreendida entre a faixa de 12 e 16 cm apresentou maior média dos valores de resistência à penetração em relação às demais camadas estudadas. O grau de dependência espacial foi classificado como moderado para todas as profundidades estudadas. Os modelos que melhor se ajustaram à distribuição espacial dos valores de resistência à penetração foram os modelos exponencial (profundidades de 12 e 16 cm) e linear (8 e 20 cm). Os dados amostrados podem incrementar um banco de dados SIG, para futuras análises e tomada de decisões quanto a procedimentos de manejo do solo.Palavras-chave: Agricultura de precisão, compactação, geoestatística. Spatial variability of soil resistance to penetration in an Oxisol ABSTRACTThe objective of this study was to evaluate the spatial variability of the penetration resistance of an Oxisol. The field experiment was installed in the Experimental Farm of the Federal University of Grande Dourados, Dourados, Mato Grosso do Sul, Brazil. An experimental area of 5.02 ha and sampling grid of 25 x 25 m, with points georeferenced using a GPS, was used. The penetration resistance was determined using a 60 cm penetrometer rod. The soil humidity in the area at the time of data collection was 18.5 % dry base . Data were analyzed using the geostatistics software GS+ and the maps were made in the software Surfer, version 8. The layer ranging between 12 and 16 cm showed higher mean resistance values than the other studied layers. The spatial dependence degree was classified as moderate for all layers. The models that best fitted the spatial distribution of the penetration resistance values were the exponential (depths of 12 and 16 cm) and linear models (8 and 20 cm). The sampled data can be used to build a GIS database for future analysis and decision making regarding the procedures for soil management.

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The aim of this study was to model the spatial variability of the nutritional status of arabic coffee using leaf macro and micronutrient contents and relate it to drop in bean yield, bark percentage and crop yield. The experiment was conducted in a plantation of arabic coffee variety Catuaí located in the Zona da Mata of Minas Gerais State. Leaf nutrient contents, cherry coffee production, drop in bean yield, yield of benefited coffee and bark percentage were determined. Data were analyzed using classical statistical methods to find the relationship between nutrients and yield variables and then examined by geostatistical analysis. The yield variables and leaf nutrients that were found related showed spatial dependence without random distribution. Nutritional imbalance was detected in the studied coffee crop expressed by the deficiency or excess of some nutrients in the plant tissue. Ca provided the smallest drop in bean yield while the leaf contents of B and Zn had an opposite effect on the production and yield of coffee.

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