Geostatistical analysis of fruit yield and detachment force in coffee

Abstract

The aim of this study was to use geostatistical analysis to evaluate the spatial variation in the detachment force of coffee fruit and coffee yield by variograms and kriging for precision agriculture. This study was conducted at Brejão farm, Três Pontas, Minas Gerais, Brazil. The detachment force of green and mature coffee fruit was measured with a prototype dynamometer and georeferenced. The yield data were obtained from manual harvesting and were georeferenced. The data were evaluated by variograms estimated by residual maximum likelihood (REML), which provided a satisfactory approach for modeling all the variables with a small sample size. Spherical and exponential models were fitted, the first provided the better fit to mature fruit detachment force and the latter provided the better fit to coffee yield and green fruit detachment force. They were used to describe the structure and magnitude of spatial variation in the variables studied. Kriged estimates were obtained with the best fitting variogram models and mapped. The statistical and geostatistical analyses enabled us to characterize the spatial variation of the detachment force of green and mature coffee fruit and coffee yield and to visualize the spatial relations among these variables. The precision agriculture techniques used in this paper to collect, map and analyze the variables studied will help coffee farmers to manage their fields. Maps of coffee yield will enable farmers to apply nutrients site-specifically and manage harvesting either manually or mechanically. In addition, maps of detachment force of coffee fruit can enable farmers to harvest coffee selectively by choosing the appropriate places and the right time to start. This will improve the quality of the final product and also increase profits.

Optimal Irrigation Mode and Spatio-Temporal Variability Characteristics of Soil Moisture Content in Different Growth Stages of Winter Wheat

“…Spatial analysis is an effective and worthwhile tool for the estimation of the spatial pattern of the regional ecological variables [11][12][13]. Spatial interpolation and estimation methods are commonly used for estimating soil characteristics of sampled specific-site data [14].…”

Spatial variability of soil pH sampled by two methodologies used in precision agriculture in farms under crop rotation

“…The robust estimator assumes that the differences Z(s+h) -Z(s) are distributed normally for all pairs (s+h, s). The transformation of the square root of differences is shown as having moments similar to those from the normal distribution and the denominator of the equation is the bias correction [9].…”

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Application of Finite Elements Method for Structural Analysis in a Coffee Harvester

“…The mechanized coffee harvest is based on vibration by canes placed in one or two vertical oscillating cylinders on the coffee harvester [15]. When the harvester is connected to a tractor which has a set of vibration operating one side plant per pass, the coffee detachment is done regardless of the alignment of coffee as result of the lateral adjustment of the set vibration.…”