The use of electromagnetic induction to detect the spatial variability of the salt and clay contents of soils

Soil Research ◽  
1987 ◽  
Vol 25 (1) ◽  
pp. 21 ◽  
Author(s):  
BG Williams ◽  
D Hoey
Keyword(s):  
Electrical Conductivity ◽  
Spatial Variability ◽  
Electromagnetic Induction ◽  
New South ◽  
Clay Material ◽  
Soluble Salts ◽  
South Wales ◽  
Apparent Electrical Conductivity ◽  
Highly Correlated ◽  
Land Use Practices

The apparent electrical conductivity (EC,) of a 250 ha area of the Riverine Plain in New South Wales was mapped using a Geonics EM 34/3 electromagnetic terrain conductivity meter. The EC, values obtained were highly correlated with both the total soluble salts and the total <2 km clay material to a depth of 15 m. The spatial variability of both these properties has a direct bearing on present and future land-use practices.

scholarly journals Measurement of apparent electrical conductivity of soil and the spatial variability of soil chemical properties by electromagnetic induction

2016 ◽  
Vol 11 (39) ◽  
pp. 3751-3762 ◽  
Author(s):  
Machado Siqueira Glecio ◽  
Dafonte Dafonte Jorge ◽  
Paz Gonzalez Antonio ◽  
Valcarcel Armesto Monteserrat ◽  
Farias de Franca e Silva Enio ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Spatial Variability ◽  
Electromagnetic Induction ◽  
Chemical Properties ◽  
Soil Chemical Properties ◽  
Apparent Electrical Conductivity

scholarly journals SPATIAL CONTINUITY OF ELECTRICAL CONDUCTIVITY, SOIL WATER CONTENT AND TEXTURE ON A CULTIVATED AREA WITH CANE SUGAR

2018 ◽  
Vol 31 (2) ◽  
pp. 434-445
Author(s):  
JUCICLÉIA SOARES DA SILVA ◽  
ÊNIO FARIAS DE FRANÇA E SILVA ◽  
GLÉCIO MACHADO SIQUEIRA ◽  
GERÔNIMO FERREIRA DA SILVA ◽  
DIEGO HENRIQUE SILVA DE SOUZA
Keyword(s):  
Electrical Conductivity ◽  
Spatial Variability ◽  
Water Content ◽  
Integrated Management ◽  
Soil Layer ◽  
Cane Sugar ◽  
Spatial Continuity ◽  
Sugarcane Crop ◽  
Saturation Extract ◽  
Apparent Electrical Conductivity

ABSTRACT Spatial variability of soil attributes affects crop development. Thus, information on its variability assists in soil and plant integrated management systems. The objective of this study was to assess the spatial variability of the soil apparent electrical conductivity (ECa), electrical conductivity of the saturation extract (ECse), water content in the soil (θ) and soil texture (clay, silt and sand) of a sugarcane crop area in the State of Pernambuco, Brazil. The study area had about 6.5 ha and its soil was classified as orthic Humiluvic Spodosol. Ninety soil samples were randomly collected and evaluated. The attributes assessed were soil apparent electrical conductivity (ECa) measured by electromagnetic induction with vertical dipole (ECa-V) in the soil layer 0.0.4 and horizontal dipole (ECa-H) in the soil layer 0.0-1.5 m; and ECse, θ and texture in the soil layers 0.0-0.2 m and 0.2-0.4 m. Spatial variability of the ECa was affected by the area relief, and had no direct correlation with the electrical conductivity of the saturation extract (ECse). The results showed overestimated mean frequency distribution, with means distant from the mode and median. The area relief affected the spatial variability maps of ECa-V, ECa-H, ECse and θ, however, the correlation matrix did not show a well-defined cause-and-effect relationship. Spatial variability of texture attributes (clay, site and sand) was high, presenting pure nugget effect.

Spatial variability in the nekton of a canal estate in southern New South Wales, Australia, and its implications for estuarine management

1995 ◽  
Vol 46 (4) ◽  
pp. 715 ◽  
Author(s):  
MP Lincoln Smith ◽  
PMH Hawes ◽  
FJ Duque-Portugal
Keyword(s):  
Spatial Variability ◽  
New South ◽  
New South Wales ◽  
South Wales ◽  
Estuarine Management ◽  
Main Canal ◽  
Number Of Individuals

The nekton of a canal development in NSW, Australia, is described. Two sites each were sampled from the main canal and in end canals. The main canal had more species of fish than did the end canals, but the number of individuals was similar between locations. Abundance of particular species showed three patterns: species that were more abundant in either location, species that varied between locations and sites, and species that did not differ significantly in abundance. There was little evidence that the nekton from the end canals, which are presumably less well flushed, was depauperate compared with the main canal. Surveys of nekton in canal estates should incorporate spatial variability at two or more scales so that the effects of these human developments can be assessed properly.

Fire studies in Mallee (Eucalyptus spp.) communities of western New South Wales: spatial and temporal fluxes in soil chemistry and soil biology following prescribed fire

1995 ◽  
Vol 2 (4) ◽  
pp. 398 ◽  
Author(s):  
J. C. Noble ◽  
D. J. Tongway ◽  
M. M. Roper ◽  
W. G. Whitford
Keyword(s):  
Electrical Conductivity ◽  
Soil Chemistry ◽  
Nitrogenase Activity ◽  
New South ◽  
New South Wales ◽  
Bare Soil ◽  
Soil Samples ◽  
Soil Biology ◽  
South Wales ◽  
Micro Organisms

The effects of prescribed fires on nutrient pools, soil micro-organisms, and vegetation patch dynamics were studied in three semi-arid mallee shrublands in western New South Wales. Repeated sampling of surface soil strata (0–2 and 2–4 cm) was undertaken at strategic times (immediately before and after the fire, after opening autumn rain, mid-season in the winter, and at the end of the spring) in five microsites (inner, middle and outer mallee litter zones, bare soil, and Triodia hummock). These samples were later analysed for pH, electrical conductivity, organic carbon and available nitrogen. The effect of fire on soil micro-organisms in these microsites was also examined by measuring nitrogenase activity and enumerating soil Acari. Carbon and nitrogen levels were consistently higher in the inner mallee microsites whereas bare soil sites provided the lowest values. Significant microsite x soil depth interactions were recorded in two shrubland sites while highly significant (P < 0.001) depth x sampling time interactions were recorded in three sites. The most sensitive soil parameter with respect to microsite was electrical conductivity, particularly in the surface 0–2 cm stratum. Highest values were again recorded from the inner mallee microsites and the lowest from bare soil sites. Nitrogenase activity was highest in soil samples associated with mallee litter and, where litter was removed by fire, activity decreased markedly except in the bare soil samples where activity was higher in the burnt samples. Soil microarthropod populations also declined notably following fire. Mites from the Prostigmata greatly outnumbered those from other suborders, a total of 12 families (15 genera) being enumerated in control sites compared with three families (three genera) only of Cryptostigmata. Nonetheless the most abundant mites were cryptostigmatids (Aphelacarus spp.) found in unburnt hummocks beneath Triodia plants. The ecological and management implications of these spatial and temporal fluxes in soil chemistry and soil biology are discussed in relation to their effects on landscape processes, particularly water and nutrient redistribution.

The distribution of net nitrogen mineralisation within surface soil. 1. Field studies under a wheat crop

Soil Research ◽  
2000 ◽  
Vol 38 (1) ◽  
pp. 129 ◽  
Author(s):  
Erry Purnomo ◽  
A. S. Black ◽  
C. J. Smith ◽  
M. K. Conyers
Keyword(s):  
Soil Depth ◽  
New South ◽  
Field Studies ◽  
Soil Disturbance ◽  
Wheat Crop ◽  
N Mineralisation ◽  
Total N ◽  
South Wales ◽  
Highly Correlated ◽  
Soil Temperature And Moisture

To test the hypothesis that net nitrogen (N) mineralisation is concentrated in the surface few centimetres following minimal soil disturbance for crop establishment, mineralisation was measured during the growth of wheat. The soil was a Red Kandosol located in southern New South Wales. Mineralisation was estimated usingin situ incubations inside capped PVC tubes, which were sampled every 3 weeks. Soil from the tubes was sampled at depth intervals of 2 cm to a depth of 10 cm and at 5-cm intervals from 10 to 20 cm. The results showed that net N mineralisation decreased with depth to 20 cm. Over the season, an average of 32% of the N mineralised in the top 20 cm of soil originated from the 0–2 cm layer, 72% was from the 0–6 cm layer, and only 13% was from soil below 10 cm. The decrease in N mineralisation with soil depth was highly correlated with decreases in the organic carbon (r2 = 0.84, P < 0.05) and total N (r2 = 0.83, P < 0.05) concentration. The soil's N-supplying ability is concentrated near the surface where it is susceptible to erosional loss. The N supply may also be inhibited by temperature and moisture extremes, which are common in the surface few centimetres of soil where mineralisation was concentrated. The PVC enclosures created artefacts in soil temperature and moisture, although it is argued that the effects on net N mineralisation were small in most sampling periods.

scholarly journals Characterization of the soil compaction based on the mapping of the apparent electrical conductivity

2021 ◽  
Vol 29 ◽  
Author(s):  
Eduardo Leonel Bottega ◽  
Eder Luís Sari ◽  
Zanandra Boff de Oliveira ◽  
Alberto Eduardo Knies
Keyword(s):  
Electrical Conductivity ◽  
Spatial Variability ◽  
Soil Compaction ◽  
Penetration Resistance ◽  
Management Zones ◽  
Mean Values ◽  
Soil Penetration Resistance ◽  
Apparent Electrical Conductivity ◽  
Moisture Conditions

Based on the measurement of soil penetration resistance (PR), it is possible to identify compacted soil layers, where root growth may be harmed, affecting crop development and yield. The objective of this work was to analyze the use of management zones (MZ), delimited on the basis of mapping of the spatial variability of the soil apparent electrical conductivity (ECa), in the differentiation of soil compaction levels. The work was carried out in a 25.8-ha no-tillage area, cultivated under a center pivot. The ECa was measured under two soil moisture conditions (13.7 and 16.45%), using the Terram® equipment. Soil penetration resistance (PR) was measured using the SoloStar PLG5500 penetrograph. Based on the spatial variability ECa mapping, management zones (2, 3, and 4 zones) were delimited. The mean PR values ??of each MZ were compared by the t-test of means. It was possible to differentiate mean values ??of penetration resistance (PR), which vary from 0.9 to 2.10 MPa, from the characterization of management classes generated on the basis of the ECa spatial variability. The highest stratification of PR values ??was obtained as a function of sampling directed at delimited management zones when the soil had lower moisture content (13.7%). The highest mean PR values ??were obtained for the split of the ECa map into at least three classes. It was identified that for the study area there is no need to perform any mechanical decompaction operation.

scholarly journals SPATIAL VARIABILITY OF SOIL APPARENT ELECTRICAL CONDUCTIVITY - EFFECT OF THE NUMBER OF SUBSAMPLES

2021 ◽  
Vol 41 (3) ◽  
pp. 396-401
Author(s):  
Emanoel Di Tarso dos S. Sousa ◽  
Daniel M. de Queiroz ◽  
Jorge T. F. Rosas ◽  
Amélia L. do Nascimento
Keyword(s):  
Electrical Conductivity ◽  
Spatial Variability ◽  
Apparent Electrical Conductivity
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