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Thematic maps are essential tools in precision agriculture to demonstrate the information of spatially distributed phenomena. A thematic map can be created from sampling data, a standard procedure for soil attributes. Interpolation methods are used to estimate data in unknown locations, such as inverse distance weighting (IDW) and ordinary Kriging (OK). For both interpolators, it is essential to use the appropriate parameters to estimate values in non-sampled locations, either the exponent value and the number of neighbors for IDW, or the theoretical model adjusted to the experimental semivariogram for OK. Thus, this trial aims at adopting additional criteria in selecting interpolators and evaluating their performance. AgDataBox platform's data interpolation module was improved, where the process of selecting the interpolator and determining its parameters considers the criteria (i) effective spatial dependence index, (ii) the first semivariance significance index, and (iii) slope of the model ends index. The experimental data come from an experiment in two agricultural areas in Brazil, using grids with good sampling density (2.7, 2.6, and 3.5 points per ha). It was observed that, usually, the application method of the three new criteria selected different models for a dataset and this must be considered in the interpolator selection process. Thematic maps varied from 0.1 to 64%, according to the coefficient of relative deviation, when comparing the three methods of applying the selection criteria. [ABSTRACT FROM AUTHOR]

• Soil physical properties were investigated in response to grazing. • Grazing caused a noticeable increase in the soil penetration resistance. • Soil physical quality was reduced due to compaction. • Decrease in physical quality can be noticed after two grazing periods. Soils in areas under grazing undergo physical changes, of greater or lower intensity, by the action of animal trampling. Thus, the objective of this study was to evaluate the spatial dependence of the physical attributes and associated soil functionalities under trampling by cattle on rotational grazing in the region of Pernambuco, Brazil. The research was conducted at the Experimental Farm of the Federal Rural University of Pernambuco, Agreste region of the State of Pernambuco, Brazil. In the field, a paddock of 0.25 ha was demarcated and four crossbred dairy cattle (Holstein-Zebu) with an average weight of 450 kg were used, managed in a rotational grazing system that included 7 days of occupation and 28 days for pasture rest. Undisturbed soil samples were collected before the first passage of the animals in the paddock and at the end of each pasture rest period, i.e., at 0, 35, 70 and 105 days of study, in a 6 × 14 m mesh, which totalled 32 sampling points. At each point, bulk density (BD), total porosity (TP), water content (W), soil penetration resistance (PR) at depths of 0.00–0.10 and 0.10–0.20 m and the soil saturated hydraulic conductivity (K 0) were determined. The data obtained were submitted to descriptive, geostatistical and multivariate statistical analysis (canonical discriminant analysis). After a period of 105 days of grazing, at both evaluated depths, an increase in the average values of PR and BD and a reduction in the values of TP, K 0 and W was observed. Normal distribution was observed in all variables studied. The physical attributes of the soil presented a coefficient of variation between low and medium and strong spatial dependence in both grazing periods. The canonical multivariate analysis indicated a reduction in the soil physical quality, especially after the animals' second passage in the paddock. [ABSTRACT FROM AUTHOR]

Soils under pastures suffer physical modifications, in greater or lesser intensity, via the action of animal trampling. Thus, the aim was to evaluate the spatial dependence of soil physical attributes under bovine trampling. The trial was performed at Roçadinho Farm, Agreste of Pernambuco, Brazil, in a 40 x 40 m paddock that was managed with continuous stocking by bovines and 12 AU ha-1 stocking rate. Soil samples were collected before and after grazing using a 6 x 6 m grid, totaling 36 sampling points. At each point, the bulk density, total porosity, moisture, soil penetration resistance at 0.00 - 0.10, 0.10 - 0.20, and 0.20 - 0.30 m depth were estimated, as was the hydraulic conductivity on the saturated soil surface. Descriptive statistics and geostatistics supported the data analysis. A normal distribution was verified for all variables, which were scored as either low or high variability in terms of the variation coefficient. The physical attributes (density, total porosity, moisture, soil penetration resistance and hydraulic conductivity) of the soil sampled presented a strong spatial dependence before and after grazing. [ABSTRACT FROM AUTHOR]

This paper compares continuous surfaces obtained by the interpolation of standard penetration test values (Nspt) by depth using deterministic and geostatistical models. The evaluation of the interpolation methods was based on the percent areas of the compactness classes by depth obtained in each method and on the percent errors calculated from the differences between the measured and interpolated Nspt. The Nspt values were obtained from 228 standard penetration tests (SPT) in situ investigations carried out in quaternary sandy marine sediments located along the Brazilian northeast coast. The boreholes are well distributed in an area of 10.9 km, covering six districts of João Pessoa City (Paraíba State, Brazil). The interpolations and analyses were conducted using geographic information system and spreadsheet software. The interpolations of Nspt values were made at depths of 1, 3, 6 and 15 m. The interpolated Nspt values obtained for each depth were classified into five soil compactness classes. The general boundaries of the compactness classes and their percent areas by depth were similar for both methods with some localized differences. Both methods presented high average percent errors and standard deviations, with a slight advantage to the geostatistical model (ordinary kriging). The minimum average percent error and standard deviation occurred at a depth of 3 m for both methods, with a slight advantage to the deterministic method (spline modified). Both methods also indicated a peculiar high soil resistance of the marine sediments at a depth of 6 m and significant areas of loose soils at a depth of 15 m in one of the districts analyzed. Both methods showed similar potential for practical applications for the initial phases of a project, not ruling out more specific SPT tests, but can optimize them. [ABSTRACT FROM AUTHOR]

This paper presents the results of electrical resistivity methods in the area delineation that was potentially contaminated by liquefaction products, which are also called putrefactive liquids in Vila Rezende municipal cemetery, Piracicaba, São Paulo, Brazil. The results indicate a depth of water table between 3.1 and 5.1 m, with two groundwater direction flows, one to the SW and another to the SE. Due to the contamination plumes, which have the same groundwater direction flow, as well the conductive anomalies observed in the geoelectric sections, the contamination suspicions in the area were confirmed. The probable plume to the SE extends beyond the limits of the cemetery. The location of the conductive anomalies and the probable contamination plumes showed that the contamination is linked with the depth of the water table and the burial time. Mapping using the geostatistical method of ordinary kriging applied to the work drew structural characteristics of the regional phenomenon and spatial behavior of the electrical resistivity data, resulting in continued surfaces. Thus, this method has proved to be an important tool for mapping contamination plumes in cemeteries. [ABSTRACT FROM AUTHOR]

• Ipomoea cavalcantei concentration is related to restrict phytophysiognomy in Canga habitat. • Mining activity is the main threat to Ipomoea cavalcantei conservation in short-term. • Restoration outside Canga habitat requires more information's. • Conservation strategies must develop alternative economic activities to mining. The Canga ecosystem, in the Eastern Brazilian Amazon, is a biodiversity and endemism hotspot as well a potential resource for iron mining, raising conflicts between conservation and economic development. Here, we collected data from 60 randomly selected points in the Canga ecosystem in the Carajás National Forest, Brazil, to analyze the spatial patterns of Ipomoea cavalcantei occurrence in different phytophysiognomies. Through ordinary kriging and a GLM model, we identified that this endemic species occupies a very restricted range within the Canga ecosystem, specifically in areas of Open Rupestrian Fields and Shrub Rupestrian Fields where the iron crust restricts the soil depth to a few centimeters and the vegetation is mainly herbaceous or savannah shrub vegetation, with low sparse tree canopies. These conditions increased the passage of sunlight, revealing the importance of light conditions for the species. However, because the species occurs in suitable mining sites, there is continuing conflict between environmental and economic decisions. Spatial data showed that mining has increased in Carajás National Forest over the last 32 years, reducing the potential locations for I. cavalcantei to less than 50 % of its original range. Mining will potentially occupy the entire species range over the next three decades. Restoration outside its original habitat is difficult in the short term, because there is no knowledge of the species' capacity for growth, survival, and replication. Conservation initiatives for the Canga ecosystem should prioritize strategies that reduce regional dependence on mining and provide alternative economic activities, such as sustainable exploitation of bio-products and ecological tourism. [ABSTRACT FROM AUTHOR]

Frankliniella schultzei (Trybom) is a serious pest of melon crops and is commonly found in the main producing areas of melon in Brazil (North and Northeast regions). This pest causes significant losses, damaging plants through feeding and tospovirus vectoring. Thus, the proper management of F. schultzei is crucial to prevent economic losses, and knowledge of the within-field distribution patterns of F. schultzei can be used to improve this pest management. This study aimed to determine the within-field distribution (through semivariogram modeling and kriging interpolation) and the factors associated with F. schultzei abundance in open-field yellow melon crops. We surveyed four yellow melon fields located in Formoso do Araguaia (Tocantins state, North Brazil) for thrips abundance in various crop stages (vegetative, flowering, and fruiting) in 2015 and 2016. Twelve models were fitted and it was determined that F. schultzei counts were strongly aggregated. The median spatial dependence was 4.79 m (range 3.55 to 8.02 m). The surface maps generated by kriging depicted an edge effect in fields 3 and 4. In addition, correlation analyses indicated that air temperature and presence of surrounding cucurbits are positively associated with F. schultzei abundance in yellow melon fields. Altogether, these insights can be combined for spatially based pest management, especially when the conditions (cucurbits in the surroundings and warmer periods) are favorable to F. schultzei., (© The Author(s) 2020. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)