Under irrigated agriculture one of the main causes of yield variability, which is the plant-available water, is controlled. In this case, other yield limitations caused by soil attributes become more relevant. To investigate the spatial variability of soil attributes and crop yields, besides the relation between chemical and physical-hydric soil attributes and crop yields of two irrigated commercial plantations (51.8 and 58.2 ha) were studied in Trindade do Sul (TS) and Palmeira das Missões (PM) respectively, in the state of […]

Studies on soil fertility mapping based on geostatistics should consider some spatial variability characteristics such as spatial continuity and absence of anisotropy. The present study reports an anisotropic analysis of the spatial variability of the following soil chemical variables: iron (Fe), potential acidity (H + Al), organic matter (OM) and manganese (Mn) of a data set of 128 plots without local chemical management, spatially referenced, studied between 1998 and 2002 in a dystrophic Red Latosol (Oxisol), in Cascavel, Paraná, Brazil. […]

The spatial variability of soil chemical attributes was evaluated in a commercial plantation under conventional soil tillage in Uberlândia, state of Minas Gerais, Brazil, in 2004. The sampling grid was the Santa Rosa Farm, where the soil is classified as very clayey Red Latosol (680 g kg-1 clay). The objective was to evaluate the spatial distribution and dependence of the soil chemical attributes in a plantation under conventional soil tillage. For this purpose, soil data were collected from a grid […]

The soils, some those considered homogenous, show some spatial and temporal variability of its physical, chemical and biological atributes. To define this variability is very important to efficient soil management. This study had the objective of investigating the spatial variability of some physical attributes of an Red Latosol in Mossoró, state of Rio Grande do Norte, Brazil, to determine the best procedure for soil sampling. Soil samples were collected on a 100 x 100 m area, in 10 m grid […]

In precision agriculture management principles must be adapted to the field variability. This requires efficient techniques to estimate and map the spatial and/or temporary variability of soil attributes and properties. However, the determination of some variables that characterize the properties of a particular soil is often onerous and troublesome. In these situations it is interesting to estimate such variables as a function of others that present good space correlation with the forner and are of simpler determination. This is possible […]

The objective of this study was to identify site-specific management zones by means of chemical soil fertility indicators on sugarcane-cultivated Latosols (Oxisols), using indicator kriging, aiming an optimized use of precision agriculture techniques. The study was conducted in a 90 ha section of a larger field (1.900 ha) near Jaboticabal, São Paulo State – Brazil (21 ° 15 ‘ S and 48 ° 18 ‘ W). A 50 m regular grid was drawn on the experimental area (300 by 3.000 m). Soil samples were obtained at each 50 m grid point (420 points) from […]

The objective of this work was to present the Analysis of Correspondence as a multivariate statistical method that can help with yield mapping interpretation. There is a concern about its indiscriminated use as a tool of predictive information, without taking into account the spatial and temporal variability of the yield. The hypothesis that the use of yield mapping is strictly related to the variability of the components was studied. Four yield maps were used corresponding to collected yield samples for […]