Integrated processing methodology to identify the spatial variability of accumulated infiltration for agricultural soil

The infiltration of water in the soil, and its variation in space, is essential to establish the irrigation schedule for crops and to evaluate the possible degrading effects on the soil. The objective was to develop an integrated processing methodology in Rstudio to identify the spatial variability of the accumulated infiltration, in two phases related to pea crops. Field sampling was carried out on a rectangular mesh with 48 points per moment, using double infiltrometer rings. The data were evaluated by means of geostatistical tools adjusted with programming code in Rstudio, defining the relationships between the magnitudes of the accumulated infiltration, for different test instants, without the need to make statistical adjustments to the normality of variables, discriminated over a period between 1 and 80 minutes. The results suggest the existence of spatial variability of the accumulated infiltration in the two evaluated phases, considering that most of the analyzed data were adjusted to multiple variance models, maintaining a degree of spatial dependence, and validating the effectiveness of the adjusted methodology developed and implemented. The spatial relationships were corroborated by means of contour maps, where the spatial variation of the accumulated infiltration between the two identified cultivation moments was observed. The reliability of the interpolation by the Ordinary Kriging method was verified by generating variance maps, establishing the degree of homogeneity of the interpolation. The variability of infiltration confirms the validity of the adjusted methodology implemented.

La infiltración del agua en el suelo y su variación espacial es fundamental para establecer la programación de riego en los cultivos y evaluar los posibles efectos degradativos en el suelo. El objetivo fue desarrollar una metodología de procesamiento integrado en Rstudio, para identificar la variabilidad espacial de la infiltración acumulada, en dos fases para un cultivo de arveja. El muestreo de campo se adelantó sobre una malla rectangular georreferenciada con 48 puntos, por cada momento, utilizando anillos infiltrómetros dobles. Los datos fueron evaluados por medio de herramientas geoestadísticas, ajustadas con código de programación en Rstudio, definiendo las relaciones entre las magnitudes de la infiltración acumulada, para diferentes instantes de prueba, sin la necesidad de realizar ajustes estadísticos de normalidad de variables, discriminados en un periodo entre 1 y 80 minutos. Los resultados sugieren la existencia de variabilidad espacial de la infiltración acumulada en las dos fases evaluadas, considerando que, la mayoría de los datos analizados, se ajustaron a múltiples modelos de semivarianza, manteniendo grados de dependencia espacial, particularmente, respecto al máximo valor acumulado de infiltración, validando la eficacia de la metodología ajustada. Las relaciones espaciales fueron corroboradas con mapas de contorno, en donde se observó la variación espacial de la infiltración acumulada entre los momentos de cultivo identificados. La confiabilidad de la interpolación por el método Kriging ordinario, se verificó mediante la generación mapas de varianza, estableciendo el grado de homogeneidad de la interpolación. La variabilidad de la infiltración confirma la validez de la metodología ajustada implementada.

Ecotoxicology and geostatistical techniques employed in subtropical reservoirs sediments after decades of copper sulfate application.

Spatial distribution linked to geostatistical techniques contributes to sum up information into an easier-to-comprehend knowledge. This study compares copper spatial distribution in surface sediments and subsequent categorization according to its toxicological potential in two reservoirs, Rio Grande (RG) and Itupararanga (ITU) (São Paulo-Brazil), where copper sulfate is applied and not applied, respectively. Sediments from 47 sites in RG and 52 sites in ITU were collected, and then, copper concentrations were interpolated using geostatistical techniques (kriging). The resulting sediment distributions were classified in categories based on sediment quality guides: threshold effect level and probable effect level; regional reference values (RRVs) and enrichment factor (EF). Copper presented a heterogenic distribution and higher concentrations in RG (2283.00 ± 1308.75 mg/kg) especially on the upstream downstream, associated with algicide application as well as the sediment grain size, contrary to ITU (21.81 ± 8.28 mg/kg) where a no-clear pattern of distribution was observed. Sediments in RG are predominantly categorized as "Very Bad", whereas sediments in ITU are mainly categorized as "Good", showing values higher than RRV. The classification is supported by the EF categorization, which in RG is primarily categorized as "Very High" contrasting to ITU classified as "Absent/Very Low". Copper total stock in superficial sediment estimated for RG is 4515.35 Ton of Cu and for ITU is 27.45 Ton of Cu.

Spatial analysis methodology of resistance to penetration and infiltration in a soil cultivated with a bushy fruit (Acca sellowiana)

The sustainable management of water and soil resources for agricultural purposes is related to the ability to store and mobilize available water for crops, particularly under a spatial analysis. The objective of the study was to design and evaluate a methodology for spatial analysis of resistance to soil penetration and infiltration on loamy-clay textures. The basic methodological principles included sampling grid planning, data capture at defined points, data fitting to empirical models, data processing, and spatial representation. A defining moment was evaluated for an established feijoa crop with permanent production. With a georeferenced rectangular sampling grid of 40m x 40m, an area of 1.36 ha was covered. Penetration resistance was measured with a penetrometer, covering 4 depths per node (sampled point). Infiltration was evaluated with ring infiltrometers. The results allowed validation of the methodology implemented through a single processing environment through RStudio. Resistance to penetration sensitively affected the variation in infiltration rates, adjusting planning activities for irrigation activities. The methodological proposal was designed to reduce processing times and graphic responses, tabulated, and integrated with a single script in the R tool, compared to traditional geostatistical techniques, which articulate the implementation of multiple tools for the generation of results.

La gestión sostenible de los recursos agua y suelo, con fines agrícolas, tiene relación con la capacidad para almacenar y movilizar agua disponible para los cultivos, particularmente, bajo un análisis espacial. El objetivo del estudio fue diseñar y evaluar una metodología de análisis espacial de la resistencia a la penetración e infiltración del suelo sobre texturas franco-arcillosas. Los principios básicos metodológicos incluyeron planificación de grilla de muestreo, captura de datos en puntos definidos, ajuste de datos a modelos empíricos, procesamiento y representación espacial de datos. Se evaluó un momento definido para un cultivo de feijoa establecido con producción permanente. Con una grilla de muestreo rectangular georreferenciada de 40m x 40m, se abarcó una superficie de 1,36 ha. La resistencia a penetración, se midió con un penetrómetro, cubriendo 4 profundidades por nodo (punto muestreado). La infiltración fue evaluada con anillos infiltrómetros. Los resultados permitieron validar la metodología implementada, mediante un entorno de procesamiento único, a través de RStudio. La resistencia a la penetración afectó sensiblemente la variación en las tasas de infiltración, ajustando actividades de planeación de actividades de riego. La propuesta metodológica fue diseñada para disminuir tiempos de procesamiento y respuestas gráficas, tabuladas e integradas en un único script en la herramienta R, comparado con técnicas tradicionales geoestadísticas, que articulan la implementación de múltiples herramientas para la generación de resultados.

Geostatistical surfaces of climatological normals of mean air temperature in Minas Gerais.

Air temperature, a vital component for the terrestrial environment sustainability, can be used as an indicator and an important factor used in short- and long-term meteorological modeling at different scales. Temperature must be monitored on spatial and temporal scale with high precision. Terrain elevation can be used as the main influence factor depending on the measurement scale. In small and medium scales, factors related to local relief were modeled with geostatistics including external variables in temperature modeling. We aimed to evaluate the use of universal kriging in the modeling of air temperature in order to create temperature surfaces at each km[Formula: see text] in Minas Gerais State, Brazil using altitude, longitude and latitude covariates. The organized mean air temperature data of climatological normals of the National Institute of Meteorology were submitted to summary statistics, statistical regression and geostatistical analysis. Monthly and annual normals of the mean air temperature compensated for the period 1981 to 2010 were modeled using temperature as dependent variable and altitude, longitude and latitude as co-variables. Multiple regression modeling performed on temperature using altitude, longitude and latitude covariates determined significant parameters for monthly and annual mean air temperature global prediction. Relief and coordinates were used as external drift on variography and universal kriging with block for local temperature interpolation and prediction in order to generate 1-km moderate resolution surfaces of monthly and annual mean air temperature. Universal kriging determined smoothing effect of standard deviation of geospatial variation with prediction errors varying between 0.6 and [Formula: see text]C. Higher prediction error values were observed between June and August. Mean air temperature local prediction presented greater errors mainly in the lower altitude regions and in the colder months. In both monthly and annual temperature predictions, universal kriging with external drift enabled to circumvent the problem of performing spatial prediction from sparse punctual attribute data, conferring a temperature downscaling effect in Minas Gerais.

Spatial distribution and colonization pattern of Bemisia tabaci in tropical tomato crops.

BACKGROUND: In precision integrated pest management, management tactics are implemented only where and when needed, by identifying the sites where the pest population has reached economic thresholds. Tomato, Solanum lycopersicum (Linn.), is a vegetable cultivated worldwide, but its production is reduced by insect pests such as the whitefly, Bemisia tabaci (Genn.). To improve management, there is a need to understand B. tabaci spatial dynamics in tomato fields, which will elucidate colonization patterns and may improve management of this pest. Thus, this study was conducted to assess the spatial autocorrelation, distribution, and colonization patterns of B. tabaci in 19 commercial tomato fields through the growing season. RESULTS: A total of 69 isotropic variograms were fit for B. tabaci. The insect distribution was aggregated with a strong level of spatial dependence. Ranges of spatial dependence varied from 0.53 to 19.05 m and 0.5 to 20 m for adults and nymphs, respectively. Overall, densities of adults and nymphs were higher and reached the economic threshold mainly at the field edges. CONCLUSION: Our results suggest a colonization pattern for B. tabaci starting at the edges and spreading inwards in to the tomato fields. This study can improve B. tabaci management in tomato fields, especially scouting and decision-making to treat fields. Scouting for this pest should be directed to the field edges, with sample points at least 20 m apart from each other for independent insect counts. © 2020 Society of Chemical Industry.

Competition for light and persistence of rare light-demanding species within tree-fall gaps in a moist tropical forest.

Current evidence suggests that tree-fall gaps can influence forest structure and dynamics by enabling certain species guilds to persist over the long term. Here we assessed the development of local size hierarchies and asymmetric competition for light in tree-fall gaps, and the role played by these two processes for the persistence of rare light-demanding species in the Barro Colorado Island Forest Dynamics Plot (Panama). We performed spatial point pattern analysis, considering both the spatial locations (x,y) and the diameter at breast height (DBH) of all the woody plant recruits from the 1985 and 2000 censuses located in tree-fall gaps, and followed their fate up to the 1990-2010 and 2005-2010 censuses, respectively. For these two recruit cohorts, we found that, from the initial census until 5-10 yr later, close neighbors presented a larger DBH than the mean DBH of all individuals within gaps, which points to a positive growth response of recruits to the increased light levels in the gap centers. However, close neighbors of the 1985 cohort also showed larger than expected DBH differences that disappeared in subsequent censuses, indicating an enhancement of size differences between neighbors and the mortality of the smaller individuals. Finally, for both recruit cohorts, we found that 10-15 yr after gap formation, surviving individuals of rare light-demanding species had a negative impact on survival of neighboring individuals of other species. Our results indicate that gaps favor the persistence of rare light-demanding species through the development of local size hierarchies and asymmetric competition for light. The strength of this process, however, apparently depends upon gap size and the role played by the woody plants already existing at the time of gap formation in early colonization. Moreover, our findings suggest that in this forest, gaps may enhance colonization of plant species typical of nearby dry tropical areas, and that, over the coming decades, similar processes could strongly modify the structure and dynamics of moist tropical forests in the region.

Variability and spatial correlation of aggregates and organic carbon in indian dark earth in Apuí region, AM / Variabilidade e correlação espacial de agregados e carbono orgânico em terra preta de índio na região do Apuí, AM

Having in mind the importance of knowing the variability and spatial correlation of soil properties in Indian Dark Earth (IDE), we evaluated in this study the variability and the spatial correlation of aggregates and carbon in an Ultisol under coffee cultivation in southern Amazonas. It was established a 48 x 88 m sampling grid spaced 06 x 08 m, totalling 88 sampling points. Then soil samples were collected at: 0.0-.05, 0.05-0.10, and 0.10-0.20 m layers. The spatial variability of the Mean Weighted Diameter (MWD) attributes, aggregates > 2 mm, < 2 mm, bulk density (BD) and organic carbon (OC) was analyzed by adjusting the simple semivariograms, while spatial correlations of the OC with aggregates and BD were analyzed by cross-semivariogram. We could conclude that there was spatial dependence in the variables, wherein the largest ones were observed at 0.0-0.05 m, except for Mean Weighted Diameter (MWD) and aggregates greater than 2.00 mm with larger range of values in depth from 0.05-0.10 and 0.10-0.20 m. The mean weight diameter and aggregate class attributes greater than 2.00 mm had negative spatial correlation with organic carbon at 0.0-0.05 m, while the smaller aggregates than 2.00 mm classes and bulk density correlated positively with organic carbon at 0.0-0.05 m and 0.10-0.20 m.

Considerando a importância do conhecimento da variabilidade e correlação espacial dos atributos do solo em Terra Preta de Índio (TPIs), avaliou-se neste trabalho a variabilidade e a correlação espacial de agregados e carbono em um Argissolo Amarelo eutrófico sob cultivo de café na região sul do Amazonas. Foi estabelecido um grid amostral com dimensões de 48 x 88 m e espaçamentos de 06 x 08 m, totalizando 88 pontos amostrais. Em seguida, foram coletadas amostras de solos nas profundidades: 0,0-0,05, 0,05-0,10, e 0,10-0,20 m. A variabilidade espacial dos atributos diâmetro médio ponderado (DMP), agregados > 2 mm, < 2 mm, densidade do solo (Ds) e carbono orgânico (CO) foi analisada ajustando os semivariogramas simples, enquanto as correlações espaciais do CO com agregados e Ds foram analisadas por semivariogramas cruzados. Concluiu-se que as variáveis apresentaram dependência espacial, e os maiores alcances são constatados na profundidade 0,0-0,05 m, exceto para DMP e agregados maiores que 2,00 mm com maiores valores de alcance na profundidade 0,05-0,10 e 0,10-0,20 m. Os atributos diâmetro médio ponderado e classes de agregados maior que 2,00 mm apresentam correlação espacial negativa com carbono orgânico na profundidade 0,0-0,05 m, enquanto a classes de agregados menor que 2,00 mm e densidade do solo apresentam correlação positiva com carbono orgânico nas profundidades 0,0-0,05 m e 0,10-0,20 m.

The spatiotemporal characteristics of environmental hazards caused by offshore oil and gas operations in the Gulf of Mexico.

Marine ecosystems are home to a host of numerous species ranging from tiny planktonic organisms, fishes, and birds, to large mammals such as the whales, manatees, and seals. However, human activities such as offshore oil and gas operations increasingly threaten marine and coastal ecosystems, for which there has been little exploration into the spatial and temporal risks of offshore oil operations. Using the Gulf of Mexico, one of the world's hottest spots of offshore oil and gas mining, as the study area, we propose a spatiotemporal approach that integrates spatial statistics and geostatistics in a geographic information system environment to provide insight to environmental management and decision making for oil and gas operators, coastal communities, local governments, and the federal government. We use the records from 1995 to 2015 of twelve types of hazards caused by offshore oil and gas operations, and analyze them spatially over a five year period. The spatial clusters of these hazards are analyzed and mapped using Getis-Ord Gi and local Moran's I statistics. We then design a spatial correlation coefficient matrix for multivariate spatial correlation, which is the ratio of the cross variogram of two types of hazards to the product of the variograms of the two hazards, showing a primary understanding of the degrees of spatial correlation among the twelve types hazards. To the best of our knowledge, it is the first application of spatiotemporal analysis methods to environmental hazards caused by offshore oil and gas operations; the proposed methods can be applied to other regions for the management and monitoring of environmental hazards caused by offshore oil operations.

Spatial variability of soil CO2 emission in a sugarcane area characterized by secondary information

Soil CO2 emission (FCO2) is governed by the inherent properties of the soil, such as bulk density (BD). Mapping of FCO2 allows the evaluation and identification of areas with different accumulation potential of carbon. However, FCO2 mapping over larger areas is not feasible due to the period required for evaluation. This study aimed to assess the quality of FCO2 spatial estimates using values of BD as secondary information. FCO2 and BD were evaluated on a regular sampling grid of 60 m × 60 m comprising 141 points, which was established on a sugarcane area. Four scenarios were defined according to the proportion of the number of sampling points of FCO2 to those of BD. For these scenarios, 67 (F67), 87 (F87), 107 (F107) and 127 (F127) FCO2 sampling points were used in addition to 127 BD sampling points used as supplementary information. The use of additional information from the BD provided an increase in the accuracy of the estimates only in the F107, F67 and F87 scenarios, respectively. The F87 scenario, with the approximate ratio between the FCO2 and BD of 1.00:1.50, presented the best relative improvement in the quality of estimates, thereby indicating that the BD should be sampled at a density 1.5 time greater than that applied for the FCO2. This procedure avoided problems related to the high temporal variability associated with FCO2, which enabled the mapping of this variable to be elaborated in large areas.

Spatial variability of soil CO2 emission in a sugarcane area characterized by secondary information

Soil CO2 emission (FCO2) is governed by the inherent properties of the soil, such as bulk density (BD). Mapping of FCO2 allows the evaluation and identification of areas with different accumulation potential of carbon. However, FCO2 mapping over larger areas is not feasible due to the period required for evaluation. This study aimed to assess the quality of FCO2 spatial estimates using values of BD as secondary information. FCO2 and BD were evaluated on a regular sampling grid of 60 m × 60 m comprising 141 points, which was established on a sugarcane area. Four scenarios were defined according to the proportion of the number of sampling points of FCO2 to those of BD. For these scenarios, 67 (F67), 87 (F87), 107 (F107) and 127 (F127) FCO2 sampling points were used in addition to 127 BD sampling points used as supplementary information. The use of additional information from the BD provided an increase in the accuracy of the estimates only in the F107, F67 and F87 scenarios, respectively. The F87 scenario, with the approximate ratio between the FCO2 and BD of 1.00:1.50, presented the best relative improvement in the quality of estimates, thereby indicating that the BD should be sampled at a density 1.5 time greater than that applied for the FCO2. This procedure avoided problems related to the high temporal variability associated with FCO2, which enabled the mapping of this variable to be elaborated in large areas.

Análise espacial de parâmetros da fertilidade do solo em região de ecótono sob diferentes usos e manejos / Spatial analysis of parameters of soil fertility in an ecotone under different uses and management

Em regiões de ecótono as características químicas do solo apresentam uma ampla variação, resultante da interrelação entre os fatores de formação, cobertura vegetal e uso. O objetivo do presente estudo foi avaliar a variabilidade espacial de atributos químicos de Neossolo Quartzarênico Órtico típico na zona de transição entre o Bioma Cerrado e o Amazônico sob diferentes formas de uso e manejo (floresta, capoeira, solo desnudo, cultura agrícola, pastagem e cerradão) na região de Araguaína (TO). Previamente a implantação do experimento foram realizadas amostragens de solo em uma malha irregular com área de 26,08 ha, na profundidade de 0 a 20 cm para determinação dos teores de matéria orgânica (M.O.), P, K+, Ca2+, Mg2+ e os valores de pH, Soma de bases (SB), capacidade de troca de cátions (CTCpH 7,0), capacidade de troca de cátions efetiva (CTCe), saturação por base (V%) e saturação por alumínio (m%). Os dados obtidos de cada um dos atributos químicos do solo foram submetidos à analises de estatística descritiva, à comparação de média pelo teste de Tukey ao nível de 5% de significância, ao estudo geoestatístico e interpolação por krigagem. Os alcances de dependência espacial dos atributos químicos M.O. Al3+, K+, Mg2+, SB e CTCe do solo foram maiores que os demais (pH, P, Ca2+, CTCpH 7, V% e m%), indicando que esses apresentam maior descontinuidade na distribuição espacial em Neossolo Quartzarênico Órtico típico sob três formas de uso agrícola e de três coberturas vegetais de zona de transição Cerrado-Amazônia. As estratégias de manejo de correção e fertilização mineral em região de ecótono podem ser montadas em função das representações dos estudos geoestatísticos e de interpolações por krigagem nas zonas mais homogêneas.

In regions of ecotone soil chemical properties show a wide variation, resulting from the interplay between the factors of formation, vegetation cover and use. The aim of this study was to evaluate the spatial variability of chemical attributes of a Entisol transition zone between the Savannah and Amazonian biome in different forms of land use and management (forest, scrub, bare soil, crop, pasture and savanna) in the region of Araguaína city (TO). Samples were ground in an irregular mesh in an area of 26.08 ha, the depth of 0 to 20 cm to determine the levels of organic matter, P, K+, Ca2+, Mg2+ and pH, sum of bases, CECpH 7, CECe, V%, m%. The soil chemical properties were analyzed using descriptive statistics, comparison of average by Tukey test at 5% significance to the study and geostatistical kriging. The ranges of spatial dependence of the chemical organic matter, Al3+, K+, Mg2+, and SB, CECe soil were higher than the others (pH, P, Ca2+, CECpH 7, V%, m%), indicating that these are more discontinuity in the spatial distribution in Entisol three forms of agricultural use and vegetation cover three of the transition Savannah-Amazon. Thus, management strategies of correction and mineral fertilizers in an ecotone can be fitted according to the representations of studies and geostatistical kriging interpolation in homogeneous areas.

Spatial analysis of parameters of soil fertility in an ecotone under different uses and management / Análise espacial de parâmetros da fertilidade do solo em região de ecótono sob diferentes usos e manejos

In regions of ecotone soil chemical properties show a wide variation, resulting from the interplay between the factors of formation, vegetation cover and use. The aim of this study was to evaluate the spatial variability of chemical attributes of a Entisol transition zone between the Savannah and Amazonian biome in different forms of land use and management (forest, scrub, bare soil, crop, pasture and savanna) in the region of Araguaína city (TO). Samples were ground in an irregular mesh in an area of 26.08 ha, the depth of 0 to 20 cm to determine the levels of organic matter, P, K+, Ca2+, Mg2+ and pH, sum of bases, CECpH 7, CECe, V%, m%. The soil chemical properties were analyzed using descriptive statistics, comparison of average by Tukey test at 5% significance to the study and geostatistical kriging. The ranges of spatial dependence of the chemical organic matter, Al3+, K+, Mg+, and SB CECe soil were higher than the others (pH, P, Ca2+, CECpH 7, V%, m%), indicating that these are more discontinuity in the spatial distribution in Entisol three forms of agricultural use and vegetation cover three of the transition Savannah-Amazon. Thus, management strategies of correction and mineral fertilizers in an ecotone can be fitted according to the representations of studies and geostatistical kriging interpolation in homogeneous areas.

Em regiões de ecótono as características químicas do solo apresentam uma ampla variação, resultante da interrelação entre os fatores de formação, cobertura vegetal e uso. O objetivo do presente estudo foi avaliar a variabilidade espacial de atributos químicos de Neossolo Quartzarênico Órtico típico na zona de transição entre o Bioma Cerrado e o Amazônico sob diferentes formas de uso e manejo (floresta, capoeira, solo desnudo, cultura agrícola, pastagem e cerradão) na região de Araguaína (TO). Previamente a implantação do experimento foram realizadas amostragens de solo em uma malha irregular com área de 26,08 ha, na profundidade de 0 a 20 cm para determinação dos teores de matéria orgânica (M.O.), P, K+, Ca2+, Mg2+ e os valores de pH, Soma de bases (SB), capacidade de troca de cátions (CTCpH 7,0), capacidade de troca de cátions efetiva (CTCe), saturação por base (V%) e saturação por alumínio (m%). Os dados obtidos de cada um dos atributos químicos do solo foram submetidos à analises de estatística descritiva, à comparação de média pelo teste de Tukey ao nível de 5% de significância, ao estudo geoestatístico e interpolação por krigagem. Os alcances de dependência espacial dos atributos químicos M.O. Al3+, K+, Mg+, SB e CTCe do solo foram maiores que os demais (pH, P, Ca2+, CTCpH 7, V% e m%), indicando que esses apresentam maior descontinuidade na distribuição espacial em Neossol