ABSTRACT In precision agriculture, accurate delineation of management zones and understanding spatial variability of soil properties and crop yields are critical for optimizing resource allocation and improving productivity. Spatial variability of different environmental factors (soil and plants) is evident in several studies. Associations between the texture and chemical properties of the soil and cowpea yield have been tested, but a large, unexplained variance of ranges between kriged maps is usually reported. This suggests that a deeper exploration into the soil […]

ABSTRACT Precision agriculture (PA) practices in banana production chains have received limited attention. Based on the literature, the investigation of spatial and temporal variability in banana orchards should be customized according to the characteristics of the crop. This study aimed to develop and evaluate methods for mapping the spatial variability in soil properties at row- and clump-resolutions in a banana orchard, and to generate row and clump maps with high-spatial-resolution soil property information. A banana orchard was investigated, and georeferenced […]

ABSTRACT: The use of management zones has ensured yield success for numerous agricultural crops. In spite of this potential, studies applying precision agricultural techniques to cacao plantations are scarce or almost nonexistent. The aim of the present study was to delineate management zones for cacao crop, create maps combining soil physical properties and cacao tree yield, and identify what combinations best fit within the soil chemical properties. The study was conducted in 2014 on a cacao plantation in a Nitossolo […]

Brazilian soils have natural high chemical variability; thus, apparent electrical conductivity (ECa) can assist interpretation of crop yield variations. We aimed to select soil chemical properties with the best linear and spatial correlations to explain ECa variation in the soil using a Profiler sensor (EMP-400). The study was carried out in Sidrolândia, MS, Brazil. We analyzed the following variables: electrical conductivity – EC (2, 7, and 15 kHz), organic matter, available K, base saturation, and cation exchange capacity (CEC). Soil […]

Frequently, soil compaction limits the yield of grain crops in mechanized lands, and its spatial distribution in the cropland is usually regionalized. In an area managed under long-term no-tillage, we investigated the relationship between soil penetration resistance (PR) and soybean yield, the effectiveness of types of chisel plows, and their effect on soybean yield. The soil from the plateau region of the state of Rio Grande do Sul, Brazil, was classified as a clayey Oxisol. The climate is subtropical (Cfa […]

Variable-rate nitrogen fertilization (VRF) based on optical spectrometry sensors of crops is a technological innovation capable of improving the nutrient use efficiency (NUE) and mitigate environmental impacts. However, studies addressing fertilization based on crop sensors are still scarce in Brazilian agriculture. This study aims to evaluate the efficiency of an optical crop sensor to assess the nutritional status of corn and compare VRF with the standard strategy of traditional single-rate N fertilization (TSF) used by farmers. With this purpose, three […]

It is well-known nowadays that soil variability can influence crop yields. Therefore, to determine specific areas of soil management, we studied the Pearson and spatial correlations of rice grain yield with organic matter content and pH of an Oxisol (Typic Acrustox) under no- tillage, in the 2009/10 growing season, in Selvíria, State of Mato Grosso do Sul, in the Brazilian Cerrado (longitude 51º24′ 21” W, latitude 20º20′ 56” S). The upland rice cultivar IAC 202 was used as test plant. […]

The spatial variability of soil and plant properties exerts great influence on the yeld of agricultural crops. This study analyzed the spatial variability of the fertility of a Humic Rhodic Hapludox with Arabic coffee, using principal component analysis, cluster analysis and geostatistics in combination. The experiment was carried out in an area under Coffea arabica L., variety Catucai 20/15 – 479. The soil was sampled at a depth 0.20 m, at 50 points of a sampling grid. The following chemical […]

Soil properties play an important role in spatial variability of crop yield. However, a low spatial correlation has generally been observed between maps of crop yield and of soil properties. The objectives of the present investigation were to assess the spatial pattern variability of soil properties and of corn yield at the same sampling intensity, and evaluate its cause-and-effect relationships. The experimental site was structured in a grid of 100 referenced points, spaced at 10 m intervals along four parallel […]

Navigation recipients of the global positioning system (GPS), widely used in the agricultural sector, in general, have a positional accuracy of < 10.0 m. In systematic soil sampling, sub-samples should be collected within a radius of not more than three meters from the central georeferenced point. In this technical note, precision and accuracy of this equipment were contrasted with the requirements of systematic soil sampling. An area of approximately 17 ha, on Campus I of the University of Passo Fundo, […]