scholarly journals SPATIAL VARIABILITY OF APPARENT ELECTRICAL CONDUCTIVITY AND PHYSICOCHEMICAL ATTRIBUTES OF THE SOIL

Author(s):  
Elizeu De Souza Lima ◽  
Lenon Henrique Lovera ◽  
Rafael Montanari ◽  
Zigomar Menezes de Souza ◽  
Jose Luiz Rodrigues Torres

The apparent electrical conductivity has been an attribute widely used in studies of spatial variability, due to its high correlation with other soil attributes and because it is an attribute that represents the variability of an area in a quick, easy and low-cost way. The objective of this study was to evaluate the relationship between the spatial variability of apparent electrical conductivity with physicochemical attributes of an Eutrophic Red Oxisol located in Maracaju, state of Mato Grosso do Sul, Brazil, for determining specific soil management zones. We analyzed apparent electrical conductivity attributes (ECa 2, 7 and 15 kHz), contents of potassium, cation exchange capacity, clay, base saturation and organic matter content. ECa was measured with the Profiler EMP-400 crossing the entire area in 0.45 m spaced lines. Soil samples were collected in the 0.000.20 m layer, with a total of 216 samples in an area of 70 ha. Statistical and geostatistical analyses were performed by SAS and GS+ software. The apparent electrical conductivity (ECa) was presented as an important tool to identify specific management zones showing data variability between low and medium zones. The attributes that had higher correlation with apparent electrical conductivity were potassium and clay.

Author(s):  
Eduardo Leonel Bottega ◽  
Eder Luís Sari ◽  
Zanandra Boff de Oliveira ◽  
Alberto Eduardo Knies

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.


2014 ◽  
Vol 34 (6) ◽  
pp. 1224-1233 ◽  
Author(s):  
Domingos S. M. Valente ◽  
Daniel M. de Queiroz ◽  
Francisco de A. de C. Pinto ◽  
Fábio L. Santos ◽  
Nerilson T. Santos

Precision agriculture based on the physical and chemical properties of soil requires dense sampling to determine the spatial variability of these properties. This dense sampling is often expensive and time-consuming. One technique used to reduce sample numbers involves defining management zones based on information collected in the field. Some researchers have demonstrated the importance of soil electrical variables in defining management zones. The objective of this study was to evaluate the relationship between the spatial variability of the apparent electrical conductivity and the soil properties in the coffee production of mountain regions. Spatial variability maps were generated using a geostatistical method. Based on the spatial variability results, a correlation analysis, using bivariate Moran's index, was done to evaluate the relationship between the apparent electrical conductivity and soil properties. The maps of potassium (K) and remaining phosphorus (P-rem) were the closest to the spatial variability pattern of the apparent electrical conductivity.


2003 ◽  
Vol 60 (3) ◽  
pp. 559-564 ◽  
Author(s):  
Edemar Joaquim Corazza ◽  
Michel Brossard ◽  
Takashi MuraokaI ◽  
Maurício Antonio Coelho Filho

Studies on soil phosphorus (P) of low productivity cultivated pastures in Cerrado (Brazilian Savanna) areas and surveys on other possible problems related to P are scarce. The spatial variability of soil phosphorus content of a Rhodic Ferralsol was studied in a low productivity pasture of Brachiaria brizantha (BB) grown for 10 years, without fertilizer application, in an experimental area at Planaltina (GO), Brazil. Soil samplings were performed on a regular grid of 10 by 10 meters, with 98 sampling points before (between tussocks and under tussocks) and after the establishment of the experiment (after fertilizing). On the same grid, forage plants were collected and separated into fractions for N and P content analyses. Soil available phosphate was determined by the resin method (Pr) and complemented by the 32P isotopic exchange kinetics analysis. Descriptive statistical and geostatistical analyses were utilized to describe the spatial variability. The Pr content on soil samples under tussocks presented mean and median values 45% larger than in soil samples taken between tussocks. The higher variation is probably related to the greater concentration of BB roots, soil organic matter content and soil P recycled through the plants tussocks. The spatial variability of Pr in this soil was high especially after fertilizer application. This variable did not present spatial dependence for the regular 10 m sampling. The generated knowledge on P variability of soils under low productivity cultivated pastures revealed problems related to the sampling methodology traditionally utilized and to P application.


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

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.


Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1567
Author(s):  
Haydee Peña ◽  
Heysa Mendoza ◽  
Fernando Diánez ◽  
Mila Santos

This work studies variables measured from the first phase of composting through the acquisition of the final product, with the goal of identifying those that are more strongly related to quality and are most useful for developing an index. The necessity to establish quality control procedures thus exists for the classification of raw materials in the same way as for the finished products. To accomplish this, three mixtures were prepared, with the goal of achieving a C/N ratio of 30 and a moisture content of 60%. The primary component of each mixture was: fruit processing waste (C1), sewage sludge from the food industry (C2), and the manufacturing waste of fried foods (C3). Temperatures were measured over 107 days, with the corresponding data fit to a logistical model where T °C ~ α / ((1 + exp (− (Time − β) / − γ))) + δ, with interaction compost * time being statistically significant (p < 0.001). This allowed for the temperatures, in keeping with health concerns, to be confirmed. Likewise, a linear regression analysis demonstrated the decomposition of organic matter at 0.82%/week. Statistically, the parameters, measured during the process, with the least variability were selected, which differed in the average contrasts: germination index (cucumber), electrical conductivity, and average moisture. A principal component analysis (PCA) and Spearman’s correlation analysis revealed the best Germination Index (GI) values for C1, due to lower electrical conductivity (EC) and bulk density (Bd) along with higher organic matter content (TOM). For its part, C2 induced a higher Relative emergence (RE) of the cucumber thanks to its higher content of total nitrogen (TN) and lower contribution of Cu, Zn and K. C3 showed a higher presence of salts, less favorable physical characteristics (>Bd and <TPS, total pore space) and higher content of Zn and Cu. Composting carried out with appropriate mixtures can offer high-quality products for use as fertiliser, in soil restoration, and as an alternative substrate to peat and virgin mountain soil.


2013 ◽  
Vol 93 (2) ◽  
pp. 205-218 ◽  
Author(s):  
Nahuel Raúl Peralta ◽  
José Luis Costa ◽  
Mónica Balzarini ◽  
Hernán Angelini

Peralta, N. R., Costa, J. L., Balzarini, M. and Angelini, H. 2013. Delineation of management zones with measurements of soil apparent electrical conductivity in the southeastern pampas. Can. J. Soil Sci. 93: 205–218. Site-specific management demands the identification of subfield regions with homogeneous characteristics (management zones). However, determination of subfield areas is difficult because of complex correlations and spatial variability of soil properties responsible for variations in crop yields within the field. We evaluated whether apparent electrical conductivity (ECa) is a potential estimator of soil properties, and a tool for the delimitation of homogeneous zones. ECamapping of a total of 647 ha was performed in four sites of Argentinean pampas, with two fields per site composed of several soil series. Soil properties and ECawere analyzed using principal components (PC)–stepwise regression and ANOVA. The PC–stepwise regression showed that clay, soil organic matter (SOM), cation exchange capacity (CEC) and soil gravimetric water content (θg) are key loading factors, for explaining the ECa(R2≥0.50). In contrast, silt, sand, extract electrical conductivity (ECext), pH values and [Formula: see text]-N content were not able to explain the ECa. The ANOVA showed that ECameasurements successfully delimited three homogeneous soil zones associated with spatial distribution of clay, soil moisture, CEC, SOM content and pH. These results suggest that field-scale ECamaps have the potential to design sampling zones to implement site-specific management strategies.


2021 ◽  
pp. 197-204
Author(s):  
Modi Ahmed ◽  
Khaliq Beg

Abstract Brunauer, Emmett, and Teller (BET) test were applied to dust samples in which samples (BET) surface area is highly related to the roundness of dust particles. The higher angularity and low roundness of the dust particles show a higher (BET) surface area. The roundness is also related to the particlesize distribution and mineralogical composition. The electrical conductivity test relates very well with the chemical and physical properties of dust samples in the transmission of an electrical current. The organic matter content was measured using the ignition method and the pH of the samples was recorded. Maps of the distribution of high and low BET concentrations, electrical conductivity EC, organic matter content, pH.


Author(s):  
Ogochukwu Ann Udume ◽  
Gideon O. Abu ◽  
Herbert Okechukwu Stanley

Water Hyacinth (Eichhornia crassipes), an aquatic macrophyte, is a resource that has attracted a lot of interest in recent times. The physicochemical constituents of Eichhornia crassipes have been reported in some literature to constitute high carbon, nitrogen, phosphorus, potassium including other important micro and macronutrient like potassium and zinc. These findings by scientists informed its utilization in the assemblage of animal feed, bio-energy generation, pharmaceutical industries, and biofilters. The bioconversions of this problematic plant to various products (compost, biochar, and digestate) are green inexpensive options to be considered for use in the restoration of hydrocarbon polluted sites is reviewed in the paper. In addition to crude oil pollution clean-ups, compost improves soil fertility and also increases its organic matter content. This article also shall review composting, Water Hyacinth compost applications in remediation, remediation monitoring parameters, limitations of remediation by composting technology, and the way forward.


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

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