Sampling Density for Characterizing the Physical Quality of a Soil Under Coffee Cultivation in Southwestern Minas Gerais

Abstract

The elaboration of maps to characterize the spatial variability of soil attributes assists in the strategic planning and decision making of agricultural managers. Precision and accuracy of maps are related to the ideal sampling density to characterize the variability pattern. This study was conducted with the aim of identifying the sampling density to represent the variability of soil physical quality using attributes with different magnitudes of variation in an area cultivated with coffee. Three approaches were used to find the most adequate sampling density (geostatistical analysis, percentage of error associated with the sampling density, and coefficient of variation). A total of 145 soil samples were collected at a depth of 0-0.20 m at the crossing points of a regular grid with a spacing of 50 m. The percentage of clay, silt, and sand, macroporosity, microporosity, total pore volume, and soil density were determined. The data were submitted to descriptive statistical analysis. For elaborating the variability maps with up to 15% error and soil attributes with a coefficient of variation close to 50%, a sampling density of 3 points ha −1 is suggested.

Precision Techniques and Agriculture 4.0 Technologies to Promote Sustainability in the Coffee Sector: State of the Art, Challenges and Future Trends

“…Through PA techniques such as semivariogram and kriging maps, several studies have analyzed the detachment force of green and red fruits in coffee crops [28], [84], [85] Other works explored the level of soil nutrients and its relationship with coffee crop productivity [80], [86]- [90], and the impact of compaction, density and soil penetration resistance (SPR) on plant productivity and development [83], [91]. Other works used sensors and geostatistics to identify the apparent soil electrical conductivity [92], to measure micronutrients and nutritional status of plants [93], and to analyze the soil fertilizer contents [94].…”