Coffee Science - v.13, n.3, 2018
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/10546
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Item Development of a methodology to determine the best grid sampling in precision coffee growing(Editora UFLA, 2018-07) Figueiredo, Vanessa Castro; Silva, Fabio Moreira da; Ferraz, Gabriel Araújo e Silva; Oliveira, Marcelo Silva de; Santos, Sthéfany Airane dosPrecision agriculture is based on a set of techniques that explore the spatial variability of properties related to a determined area. The aim of this study was to develop and test a methodology to evaluate the quality of grid sampling. The experiment was performed in three areas of 112, 50 and 26 ha, in coffee plantations (Coffea arabica ) with cultivar Catuai 144, in the Três Pontas Farm, located in Presidente Olegário, MG, Brazil, in 2014 and 2015. A total of 224, 100, and 52 georeferenced points (2.0 points/ha) were plotted in the areas regarding the soil chemical properties, respectively: phosphorus, potassium, calcium and magnesium. For the application methodology the standardized accuracy index (SAI), the standardized precision index (SPI) and the standardized optimal grid indicator (SOGI) were developed and tested. From grid 1 (2 points/ha), another three sampling grids (1.0, 0.7 and 0.5 point/ha) were adopted. The indexes were important to analyze the grid quality, whereas the SOGI allowed selecting the grid that best represented the properties.Item Spatial variability of soil penetration resistance in coffee growing(Editora UFLA, 2018-07) Andrade, Alan Delon; Faria, Rafael de Oliveira; Alonso, Diego José Carvalho; Ferraz, Gabriel Araújo e Silva; Herrera, Miguel Angel Diaz; Silva, Fábio Moreira daThe intensive use of machines in agriculture tends to cause soil compaction, which can hamper the expansion of root system and the absorption of water and nutrients, thus affecting the crop development. In view of the above, the present study aimed to identify critical zones of soil compaction, through the spatial distribution of soil penetration resistance (SPR), having positions within the coffee rows and soil depth ranges as variables. The study was performed in a coffee plantation of 7.32 ha, belonging to the Bom Jardim Farm, located in the municipality of Bom Sucesso, MG, Brazil. The SPR was measured using a penetrometer in the depth range from 0 to 0.40 m, with discretization in four layers of 0.10 m. The data were interpreted based on geostatistics, in order to identify if there is spatial dependence of the SPR and generate thematic maps demonstrating the variable’s spatial behavior. It is concluded that there is spatial dependence of soil penetration resistance, being possible to use geostatistical tools to generate thematic maps based on classes of soil penetration resistance. The values of SPR in the tractor trail, for layers from 0.10 to 0.20 and from 0.20 to 0.30 m, were classified in the high SPR class and could cause damage to the crop.