scholarly journals CONDUTIVIDADE ELÉTRICA DO EXTRATO DE SATURAÇÃO DO SOLO A PARTIR DE EXTRATOS 1:2 PELO MÉTODO DO EIXO PRINCIPAL REDUZIDO

Irriga ◽  
2005 ◽  
Vol 10 (4) ◽  
pp. 351-356
Author(s):  
Daniel Da Costa Dantas ◽  
José De Arimatea de Matos ◽  
José Francismar de Medeiros ◽  
Francisco De Queiroz Porto Filho ◽  
Neyton De Oliveira Miranda
Keyword(s):  
Electrical Conductivity ◽  
Linear Regression ◽  
Cucumis Melo ◽  
Major Axis ◽  
Soil Electrical Conductivity ◽  
Soil Extracts ◽  
Saturated Water ◽  
Different Depths ◽  
Reduced Major Axis ◽  
Soil And Water

CONDUTIVIDADE ELÉTRICA DO EXTRATO DE SATURAÇÃO DO SOLO A PARTIR DE EXTRATOS 1:2 PELO MÉTODO DO EIXO PRINCIPAL REDUZIDO  Daniel da Costa Dantas; José de Arimatea de Matos; José Francismar de Medeiros; Francisco de Queiroz Porto Filho; Neyton de Oliveira MirandaDepartamento de Ciências Ambientais, Universidade Federal Rural do Semi Árido, Mossoró, RN, [email protected]  1        RESUMO Com o objetivo de estimar a condutividade elétrica de extratos de saturação do solo (CEes) em função de extratos do solo 1:2 (CE1:2), procedeu-se o monitoramento da salinidade do solo em um experimento com melão irrigado com água de diferentes níveis de salinidade (S1 = 0,6; S2 = 1,9; S3 = 3,2 e S4 = 4,5 dS m-1), aplicada de forma incremental ao longo do ciclo. Coletaram-se amostras de solo para análise em três profundidades (0-15, 15-30 e 30-45 cm), durante dois ciclos de cultivo, aos 70 dias após a semeadura (DAS) no primeiro ciclo e aos 30 e 70 DAS no segundo. Determinou-se a CE1:2 e a CEes em amostras compostas, resultante de 15 tratamentos com três profundidades para cada tratamento. Os dados foram ajustados por profundidade e em conjunto, através de funções lineares de regressão e pelo método do eixo principal reduzido (EPR). A equação CEes = 8,094 CE1:2 + 0,0149 (R2 = 0,9112), desenvolvida através do eixo principal reduzido para todos os dados, apresentou nível de estimabilidade semelhante às equações obtidas para as diferentes profundidades e épocas e que a CE é inversamente proporcional a razão entre água:solo. UNITERMOS: Cucumis melo, salinidade.  DANTAS, D. da C.; MATOS, J. de. A. de; MEDEIROS, J. F. de; PORTO FILHO, F. de. Q.; MIRANDA, N. de. O.; ELECTRICAL CONDUCTIVITY OF SATURATED EXTRACTSDETERMINED BY THE REDUCED MAJOR AXIS METHOD USING MIXTURES OF SOIL AND WATER IN A 1:2 RATIO  2  ABSTRACT This experiment was carried out aiming to estimate electrical conductivity of saturated water soil extracts (CEes) using mixtures of soil and water in a 1:2 ratio (CE1:2). Soil salinity was monitored in a field where melon was irrigated with water which salinity level was increasing during the cycle (S1 = 0.6; S2 = 1.9; S3 = 3.2 and S4 = 4.5 dS m-¹). Samples were taken from two consecutive melon cycles at three depths (0-15, 15-30 and 30-45 cm). At 70 days after seeding (DAS) of the first cycle and at 30 and 70 DAS of the second CEes and CE1:2 were determined from compounded samples taken from 15 treatments with three depths each. Data were adjusted for all data and depth using linear regression and the reduced major axis method (RMA). The equation CEes = 8.094 CE1:2 + 0.0149 (R² = 0.9112) obtained using all data through RMA, showed a degree of predictability similar to the linear regression obtained for different depths and dates. Soil electrical conductivity was inversely correlated to the soil:water ratio. KEYWORDS: Cucumis melo, salinity

Estimation of response slopes in respiratory control

1984 ◽  
Vol 56 (2) ◽  
pp. 536-539 ◽  
Author(s):  
D. L. Sherrill ◽  
G. D. Swanson
Keyword(s):  
Statistical Approach ◽  
Ventilatory Response ◽  
Respiratory Control ◽  
Major Axis ◽  
Bivariate Normal Distribution ◽  
Directional Statistics ◽  
Control Behavior ◽  
Slope Estimate ◽  
Partial Pressure Of Co2 ◽  
Reduced Major Axis

The ventilatory response to changes in alveolar (arterial) CO2 is widely used as an index of respiratory control behavior. Methods for estimating these response slopes should incorporate the possibility that there may be errors in both the independent (partial pressure of CO2) and dependent (ventilation) variables. In a recent paper Daubenspeck and Ogden (J. Appl. Physiol. Respirat. Environ. Exercise Physiol. 45:823–829, 1978) have suggested problems inherent in the traditional technique of reduced major axis and have suggested a more contemporary technique of directional statistics. We have previously analyzed both techniques and developed a method to overcome the problems of reduced major axis and problems inherent in the use of directional statistics. Under the assumption of a bivariate normal distribution, we demonstrate that our slope estimate is similar to the maximum likelihood estimate proposed by Mardia et al. (J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 54: 309–313, 1983) for this problem. In addition, we demonstrate a bootstrap statistical approach when the distributions are not normally distributed. These concepts are illustrated using O2-CO2 interaction data.

scholarly journals Spatial and Temporal Variability of Soil Salinity in the Yangtze River Estuary Using Electromagnetic Induction

2021 ◽  
Vol 13 (10) ◽  
pp. 1875
Author(s):  
Wenping Xie ◽  
Jingsong Yang ◽  
Rongjiang Yao ◽  
Xiangping Wang
Keyword(s):  
Electrical Conductivity ◽  
Spatial Distribution ◽  
Soil Salinity ◽  
Yangtze River ◽  
Laboratory Data ◽  
River Estuary ◽  
Yangtze River Estuary ◽  
Soil Electrical Conductivity ◽  
The Yangtze River ◽  
The Yangtze River Estuary

Soil salt-water dynamics in the Yangtze River Estuary (YRE) is complex and soil salinity is an obstacle to regional agricultural production and the ecological environment in the YRE. Runoff into the sea is reduced during the impoundment period as the result of the water-storing process of the Three Gorges Reservoir (TGR) in the upper reaches of the Yangtze River, which causes serious seawater intrusion. Soil salinity is a problem due to shallow and saline groundwater under serious seawater intrusion in the YRE. In this research, we focused on the temporal variation and spatial distribution characteristics of soil salinity in the YRE using geostatistics combined with proximally sensed information obtained by an electromagnetic induction (EM) survey method in typical years under the impoundment of the TGR. The EM survey with proximal sensing method was applied to perform soil salinity survey in field in the Yangtze River Estuary, allowing quick determination and quantitative assessment of spatial and temporal variation of soil salinity from 2006 to 2017. We developed regional soil salinity survey and mapping by coupling limited laboratory data with proximal sensed data obtained from EM. We interpreted the soil electrical conductivity by constructing a linear model between the apparent electrical conductivity data measured by an EM 38 device and the soil electrical conductivity (EC) of soil samples measured in laboratory. Then, soil electrical conductivity was converted to soil salt content (soil salinity g kg−1) through established linear regression model based on the laboratory data of soil salinity and soil EC. Semivariograms of regional soil salinity in the survey years were fitted and ordinary kriging interpolation was applied in interpolation and mapping of regional soil salinity. The cross-validation results showed that the prediction results were acceptable. The soil salinity distribution under different survey years was presented and the area of salt affected soil was calculated using geostatistics method. The results of spatial distribution of soil salinity showed that soil salinity near the riverbanks and coastlines was higher than that of inland. The spatial distribution of groundwater depth and salinity revealed that shallow groundwater and high groundwater salinity influenced the spatial distribution characteristics of soil salinity. Under long-term impoundment of the Three Gorges Reservoir, the variation of soil salinity in different hydrological years was analyzed. Results showed that the area affected by soil salinity gradually increased in different hydrological year types under the impoundment of the TGR.

scholarly journals The Relationship between Soil Electrical Parameters and Compaction of Sandy Clay Loam Soil

Agriculture ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 114
Author(s):  
Katarzyna Pentoś ◽  
Krzysztof Pieczarka ◽  
Kamil Serwata
Keyword(s):  
Electrical Conductivity ◽  
Magnetic Susceptibility ◽  
Precision Agriculture ◽  
Soil Compaction ◽  
Soil Layer ◽  
Soil Parameters ◽  
Soil Electrical Conductivity ◽  
Electrical Parameters ◽  
Management Zones ◽  
Additional Information

Soil spatial variability mapping allows the delimitation of the number of soil samples investigated to describe agricultural areas; it is crucial in precision agriculture. Electrical soil parameters are promising factors for the delimitation of management zones. One of the soil parameters that affects yield is soil compaction. The objective of this work was to indicate electrical parameters useful for the delimitation of management zones connected with soil compaction. For this purpose, the measurement of apparent soil electrical conductivity and magnetic susceptibility was conducted at two depths: 0.5 and 1 m. Soil compaction was measured for a soil layer at 0–0.5 m. Relationships between electrical soil parameters and soil compaction were modelled with the use of two types of neural networks—multilayer perceptron (MLP) and radial basis function (RBF). Better prediction quality was observed for RBF models. It can be stated that in the mathematical model, the apparent soil electrical conductivity affects soil compaction significantly more than magnetic susceptibility. However, magnetic susceptibility gives additional information about soil properties, and therefore, both electrical parameters should be used simultaneously for the delimitation of management zones.

scholarly journals Investigation of the relationship between landform classes and electrical conductivity (EC) of water and soil using a fuzzy model in a GIS environment

Solid Earth ◽  
2016 ◽  
Vol 7 (3) ◽  
pp. 873-880
Author(s):  
Marzieh Mokarram ◽  
Dinesh Sathyamoorthy
Keyword(s):  
Electrical Conductivity ◽  
Fuzzy Model ◽  
Chemical Properties ◽  
Geographical Information ◽  
Fars Province ◽  
Fuzzy Method ◽  
The North ◽  
The Relationship ◽  
Very High ◽  
Soil And Water

Abstract. Soil genesis is highly dependent on landforms as they control the erosional processes and the soil physical and chemical properties. The relationship between landform classification and electrical conductivity (EC) of soil and water in the northern part of Meharloo watershed, Fars province, Iran, was investigated using a combination of a geographical information system (GIS) and a fuzzy model. The results of the fuzzy method for water EC showed 36.6 % of the land to be moderately land suitable for agriculture; high, 31.69 %; and very high, 31.65 %. In comparison, the results of the fuzzy method for soil EC showed 24.31 % of the land to be as not suitable for agriculture (low class); moderate, 11.78 %; high, 25.74 %; and very high, 38.16 %. In total, the land suitable for agriculture with low EC is located in the north and northeast of the study area. The relationship between landform and EC shows that EC of water is high for the valley classes, while the EC of soil is high in the upland drainage class. In addition, the lowest EC levels for soil and water are in the plains class.

Sign in / Sign up

Export Citation Format

Share Document