Digital soil mapping: evaluation of sampling systems for soil surveys and refinement of soil maps at lower cost using legacy data

In soil surveys, several sampling systems can be used to define the most representative sites for sample collection and description of soil profiles. In recent years, the conditioned Latin hypercube sampling system has gained prominence for soil surveys. In Brazil, most of the soil maps are at small scales and in paper format, which hinders their refinement. The objectives of this work include: (i) to compare two sampling systems by conditioned Latin hypercube to map soil classes and soil properties; (II) to retrieve information from a detailed scale soil map of a pilot watershed for its refinement, comparing two data mining tools, and validation of the new soil map; and (III) to create and validate a soil map of a much larger and similar area from the extrapolation of information extracted from the existing soil map. Two sampling systems were created by conditioned Latin hypercube and by the cost-constrained conditioned Latin hypercube. At each prospection place, soil classification and measurement of the A horizon thickness were performed. Maps were generated and validated for each sampling system, comparing the efficiency of these methods. The conditioned Latin hypercube captured greater variability of soils and properties than the cost-constrained conditioned Latin hypercube, despite the former provided greater difficulty in field work. The conditioned Latin hypercube can capture greater soil variability and the cost-constrained conditioned Latin hypercube presents great potential for use in soil surveys, especially in areas of difficult access. From an existing detailed scale soil map of a pilot watershed, topographical information for each soil class was extracted from a Digital Elevation Model and its derivatives, by two data mining tools. Maps were generated using each tool. The more accurate of these tools was used for extrapolation of soil information for a much larger and similar area and the generated map was validated. It was possible to retrieve the existing soil map information and apply it on a larger area containing similar soil forming factors, at much low financial cost. The KnowledgeMiner tool for data mining, and ArcSIE, used to create the soil map, presented better results and enabled the use of existing soil map to extract soil information and its application in similar larger areas at reduced costs, which is especially important in development countries with limited financial resources for such activities, such as Brazil.

Distribuição espacial e plano de amostragem seqüencial de ácaros fitófagos na cultura da seringueira [Hevea brasiliensis (Wild. Ex Adr. de Juss.) Müell.Arg.]

Pós-graduação em Agronomia - FEIS

Comparação entre os estimadores de mínimos quadrados ordinários e mínimos desvios absolutos em modelos de regressão linear simples -: uma aplicação na energia na agricultura

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Análise da curva de crescimento de bovinos da raça Nelore utilizando funções não-lineares em análises Bayesianas: Selma Forni. -

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Rastreabilidade de farinhas de origem animal em ovos de poedeiras comerciais pela técnica dos isótopos estáveis do carbono 'delta' 'INTPOT.13 C' do nitrogênio 'delta' 'INTPOT.15 N'

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Optimization of the sampling scheme for maps of physical and chemical properties estimated by kriging

The sampling scheme is essential in the investigation of the spatial variability of soil properties in Soil Science studies. The high costs of sampling schemes optimized with additional sampling points for each physical and chemical soil property, prevent their use in precision agriculture. The purpose of this study was to obtain an optimal sampling scheme for physical and chemical property sets and investigate its effect on the quality of soil sampling. Soil was sampled on a 42-ha area, with 206 geo-referenced points arranged in a regular grid spaced 50 m from each other, in a depth range of 0.00-0.20 m. In order to obtain an optimal sampling scheme for every physical and chemical property, a sample grid, a medium-scale variogram and the extended Spatial Simulated Annealing (SSA) method were used to minimize kriging variance. The optimization procedure was validated by constructing maps of relative improvement comparing the sample configuration before and after the process. A greater concentration of recommended points in specific areas (NW-SE direction) was observed, which also reflects a greater estimate variance at these locations. The addition of optimal samples, for specific regions, increased the accuracy up to 2 % for chemical and 1 % for physical properties. The use of a sample grid and medium-scale variogram, as previous information for the conception of additional sampling schemes, was very promising to determine the locations of these additional points for all physical and chemical soil properties, enhancing the accuracy of kriging estimates of the physical-chemical properties.

Severity of temporomandibular disorders in women: validity and reliability of the Fonseca Anamnestic Index

The aim of this study was to assess the validity and reliability of the Fonseca Anamnestic Index (IAF), used to assess the severity of temporomandibular disorders, applied to Brazilian women. We used a probabilistic sampling design. The participants were 700 women over 18 years of age, living in the city of Araraquara (SP). The IAF questionnaire was applied by telephone interviews. We conducted Confirmatory Factor Analysis (CFA) using Chi-Square Over Degrees of Freedom (χ2/df), Comparative Fit Index (CFI), Tucker-Lewis Index (TLI), and Root Mean Square Error of Approximation (RMSEA) as goodness of fit indices. We calculated the convergent validity, the average variance extracted (AVE) and the composite reliability (CR). Internal consistency was assessed by Cronbach's alpha coefficient (α).The factorial weights of questions 8 and 10 were below the adequate values. Thus, we refined the original model and these questions were excluded. The resulting factorial model showed appropriate goodness of fit to the sample (χ2/df = 3.319, CFI = 0.978, TLI = 0.967, RMSEA = 0.058). The convergent validity (AVE = 0.513, CR = 0.878) and internal consistency (α = 0.745) were adequate. The reduced IAF version showed adequate validity and reliability in a sample of Brazilian women.

Convergence Property of the Measurement Gross Error Correction in Power System State Estimation, Using Geometrical Background

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Empirical models for estimating the suspended sediment concentration in Amazonian white water rivers using Landsat 5/TM

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Número de amostras na análise geoestatística e na krigagem de mapas de atributos do solo

The objective of this study was to analyze different intensities of soil sampling for accuracy in geostatistical analysis and interpolation maps for precision agriculture in the sugarcane area. Soil samples were collected at two regular grids at a depth of 0.00 to 0.20m for granulometric analysis (area 1) and soil fertility (area 2). We compared soil sampling intensities: 208, 105, 58 and 24 points in Area 1 and 206, 102 and 53 points in Area 2. The data were submitted to descriptive analysis and geostatistics. The variograms constructed with 105 points didn't differ from variograms with 208 points, which doesn't occur for 58 and 24 points. The increase of sampling interval and reducing the number of points promote greater error in kriging. Samples with more than 100 points per area did not result in significant improvements in the error of kriging, or differed in the amount of fertilizer applied to the field.

Economic design of Shewhart control charts for monitoring autocorrelated data with skip sampling strategies

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A new sampling strategy to reduce the effect of autocorrelation on a control chart

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Tamanho da amostra foliar para avaliação do estado nutricional e índice SPAD de capim-elefante irrigado para corte

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sequential sampling of soybean and beans seeds for Sclerotinia sclerotiorum detection (Lib.) DeBary

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A Sampling Plan for Liriomyza huidobrensis (Diptera: Agromyzidae) on a Potato (Solanum tuberosum) Plantation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)