scholarly journals Effects of soil depth on the dynamics of selected soil properties among the highlands resources of Northeast Wollega, Ethiopia: are these sign of degradation?

2015 ◽  
Vol 7 (3) ◽  
pp. 2011-2035 ◽  
Author(s):  
A. Adugna ◽  
A. Abegaz

Abstract. This study was conducted with an aim to analyze the spatial variability of soil properties with depth under four prominent land use patterns viz., forestland, grazing land, cultivated land and bush land of Northeast Wollega. Soil samples were collected from the land uses at two depths (0–15 and 15–30 cm) in replicates and totally 40 composite soil samples were collected. Statistical analysis revealed significant variation in soil properties with along the selected land uses. Topsoil layer had significantly greater OM, TN, AP, sand, silt, Mg2+, K+ and Mg2+ concentrations than the subsoil layers. However, clay under all land uses and CEC under bush land and grazing land revealed reverse trends. Organic matter and CEC have stronger correlations with most of soil properties in the topsoil than in the subsoil while clay has no significant correlation with selected soil properties except with sand fraction in the sampled depths. Hence, the correlation among the selected soil properties also varies with soil depth. In general, the spatial variability of soil properties indicates that they were strongly affected by external factors (agricultural treatments and soil management practices) and internal factors (soil type and depth).

2015 ◽  
Vol 39 (6) ◽  
pp. 1755-1763 ◽  
Author(s):  
James Ribeiro de Azevedo ◽  
Célia Regina Paes Bueno ◽  
Gener Tadeu Pereira

ABSTRACT The study of soil chemical and physical properties variability is important for suitable management practices. The aim of this study was to evaluate the spatial variability of soil properties in the Malhada do Meio settlement to subsidize soil use planning. The settlement is located in Chapadinha, MA, Brazil, and has an area of 630.86 ha. The vegetation is seasonal submontane deciduous forest and steppe savanna. The geology is formed of sandstones and siltstones of theItapecuru Formation and by colluvial and alluvial deposits. The relief consists of hills with rounded and flat tops with an average altitude of 67 m, and frequently covered over by ferruginous duricrusts. A total of 183 georeferenced soil samples were collected at the depth of 0.00-0.20 m inPlintossolos, Neossolo andGleissolo. The following chemical variables were analyzed: pH(CaCl2), H+Al, Al, SB, V, CEC, P, K, OM, Ca, Mg, SiO2, Al2O3, and Fe2O3; along with particle size variables: clay, silt, and sand. Descriptive statistical and geostatistical analyses were carried out. The coefficient of variation (CV) was high for most of the variables, with the exception of pH with a low CV, and of sand with a medium CV. The models fitted to the experimental semivariograms of these variables were the exponential and the spherical. The range values were from 999 m to 3,690 m. For the variables pH(CaCl2), SB, and clay, there are three specific areas for land use planning. The central part of the area (zone III), where thePlintossolos Pétricos and Neossolos Flúvicos occur, is the most suitable for crops due to higher macronutrient content, organic matter and pH. Zones I and II are indicated for environmental preservation.


2015 ◽  
Vol 7 (1) ◽  
pp. 301-327 ◽  
Author(s):  
V. Ferreira ◽  
T. Panagopoulos ◽  
R. Andrade ◽  
C. Guerrero ◽  
L. Loures

Abstract. The aim of this work is to investigate how the spatial variability of soil properties and soil erodibility (K factor) were affected by the changes in land use allowed by irrigation with water from a reservoir in a semiarid area. To this, three areas representative of different land uses (agroforestry grassland, Lucerne crop and olive orchard) were studied within a 900 ha farm. The interrelationships between variables were analyzed by multivariate techniques and extrapolated using geostatistics. The results confirmed differences between land uses for all properties analyzed, which was explained mainly by the existence of diverse management practices (tillage, fertilization and irrigation), vegetation cover and local soil characteristics. Soil organic matter, clay and nitrogen content decreased significantly, while K factor increased with intensive cultivation. The HJ-biplot methodology was used to represent the variation of soil erodibility properties grouped in land uses. Native grassland was the least correlated with the other land uses. K factor demonstrated high correlation mainly with very fine sand and silt. The maps produced with geostatistics were crucial to understand the current spatial variability in the Alqueva region. Facing the intensification of land-use conversion, a sustainable management is needed to introduce protective measures to control soil erosion.


PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0253156
Author(s):  
Gizachew Ayalew Tiruneh ◽  
Tiringo Yilak Alemayehu ◽  
Derege Tsegaye Meshesha ◽  
Eduardo Saldanha Vogelmann ◽  
José Miguel Reichert ◽  
...  

The understanding of the spatial variation of soil chemical properties is critical in agriculture and the environment. To assess the spatial variability of soil chemical properties in the Fogera plain, Ethiopia, we used Inverse Distance Weighting (IDW), pair-wise comparisons, descriptive analysis, and principal component analysis (PCA). In 2019, soil samples were collected at topsoil (a soil depth of 0–20 cm) from three representative land-uses (cropland, plantation forestland, and grazing lands) using a grid-sampling design. The variance analysis for soil pH, available phosphorus (avP), organic carbon (OC), total nitrogen (TN), electrical conductivity (EC), exchangeable potassium (exchK), exchangeable calcium (exchCa), and cation exchange capacity (CEC) revealed significant differences among the land-uses. The highest mean values of pH (8.9), avP (32.99 ppm), OC (4.82%), TN (0.39%), EC (2.28 dS m−1), and exchK (2.89 cmol (+) kg-1) were determined under grazing land. The lowest pH (6.2), OC (2.3%), TN (0.15%), and EC (0.11 dS m−1) were recorded in cultivated land. The PCA result revealed that the land-use change was responsible for most soil chemical properties, accounting for 93.32%. Soil maps can help identify the nutrient status, update management options, and increase productivity and profit. The expansion of cultivated lands resulted in a significant decrease in soil organic matter. Thus, soil management strategies should be tailored to replenish the soil nutrient content while maintaining agricultural productivity in the Fogera plain.


Solid Earth ◽  
2015 ◽  
Vol 6 (2) ◽  
pp. 383-392 ◽  
Author(s):  
V. Ferreira ◽  
T. Panagopoulos ◽  
R. Andrade ◽  
C. Guerrero ◽  
L. Loures

Abstract. The aim of this work is to investigate how the spatial variability of soil properties and soil erodibility ($K$ factor) were affected by the changes in land use allowed by irrigation with water from a reservoir in a semiarid area. To this end, three areas representative of different land uses (agroforestry grassland, lucerne crop and olive orchard) were studied within a 900 ha farm. The interrelationships between variables were analyzed by multivariate techniques and extrapolated using geostatistics. The results confirmed differences between land uses for all properties analyzed, which was explained mainly by the existence of diverse management practices (tillage, fertilization and irrigation), vegetation cover and local soil characteristics. Soil organic matter, clay and nitrogen content decreased significantly, while the K factor increased with intensive cultivation. The HJ-Biplot methodology was used to represent the variation of soil erodibility properties grouped in land uses. Native grassland was the least correlated with the other land uses. The K factor demonstrated high correlation mainly with very fine sand and silt. The maps produced with geostatistics were crucial to understand the current spatial variability in the Alqueva region. Facing the intensification of land-use conversion, a sustainable management is needed to introduce protective measures to control soil erosion.


2018 ◽  
Vol 10 (7) ◽  
pp. 2522 ◽  
Author(s):  
Ivan Viveros Santos ◽  
Cécile Bulle ◽  
Annie Levasseur ◽  
Louise Deschênes

Life cycle assessment has been recognized as an important decision-making tool to improve the environmental performance of agricultural systems. Still, there are certain modelling issues related to the assessment of their impacts. The first is linked to the assessment of the metal terrestrial ecotoxicity impact, for which metal speciation in soil is disregarded. In fact, emissions of metals in agricultural systems contribute significantly to the ecotoxic impact, as do copper-based fungicides applied in viticulture to combat downy mildew. Another issue is linked to the ways in which the intrinsic geographical variability of agriculture resulting from the variation of management practices, soil properties, and climate is addressed. The aim of this study is to assess the spatial variability of the terrestrial ecotoxicity impact of copper-based fungicides applied in European vineyards, accounting for both geographical variability in terms of agricultural practice and copper speciation in soil. This first entails the development of regionalized characterization factors (CFs) for the copper used in viticulture and then the application of these CFs to a regionalized life-cycle inventory that considers different management practices, soil properties, and climates in different regions, namely Languedoc-Roussillon (France), Minho (Portugal), Tuscany (Italy), and Galicia (Spain). There are two modelling alternatives to determine metal speciation in terrestrial ecotoxicity: (a) empirical regression models; and (b) WHAM 6.0, the geochemical speciation model applied according to the soil properties of the Harmonized World Soil Database (HWSD). Both approaches were used to compute and compare regionalized CFs with each other and with current IMPACT 2002+ CF. The CFs were then aggregated at different spatial resolutions—global, Europe, country, and wine-growing region—to assess the uncertainty related to spatial variability at the different scales and applied in the regionalized case study. The global CF computed for copper terrestrial ecotoxicity is around 3.5 orders of magnitude lower than the one from IMPACT 2002+, demonstrating the impact of including metal speciation. For both methods, an increase in the spatial resolution of the CFs translated into a decrease in the spatial variability of the CFs. With the exception of the aggregated CF for Portugal (Minho) at the country level, all the aggregated CFs derived from empirical regression models are greater than the ones derived from the method based on WHAM 6.0 within a range of 0.2 to 1.2 orders of magnitude. Furthermore, CFs calculated with empirical regression models exhibited a greater spatial variability with respect to the CFs derived from WHAM 6.0. The ranking of the impact scores of the analyzed scenarios was mainly determined by the amount of copper applied in each wine-growing region. However, finer spatial resolutions led to an impact score with lower uncertainty.


Urban Studies ◽  
2018 ◽  
Vol 55 (16) ◽  
pp. 3650-3668 ◽  
Author(s):  
Sofia Pagliarin

Governance dynamics and spatial planning regulations are significant factors in the occurrence (or containment) of urban sprawl. However, qualitative investigations of the planning regulatory systems and practices, and governance arrangements that cumulatively stimulate suburbanisation, typically remain detached from land-change analyses. Based on the concept of institutional frames of spatial planning systems, this article elucidates how governance dynamics and spatial planning practices, at different scales, can partially explain suburban land-use patterns. The territorial transformations of two Southern European metropolitan regions, Barcelona and Milan, are examined through land-use data (1990–2012) at different territorial scales. Demographic (1991–2011) and administrative (2011) data are also analysed. In-depth interviews about individual and collective land management practices have been carried out, as well as document analysis concerning spatial planning laws and regulations. This research shows that the metropolitan character of urban sprawl originates from local planning practices mainly performed by municipal authorities through land-use micro-transformations. Further, it highlights the decisive role that higher-level institutions can play in land containment. Urban sprawl is hence not necessarily an unplanned phenomenon, but rather a ‘differently planned’ local and regional land-use strategy.


2019 ◽  
Vol 886 ◽  
pp. 3-7 ◽  
Author(s):  
Wutthikrai Kulsawat ◽  
Boonsom Porntepkasemsan ◽  
Phatchada Nochit

Paddy residues are the most generous agricultural biomass from the paddy cultivation, Paddy residues practices include crop residue amendment and in-situ burning. It indicated that residue amendment increased the organic carbon and nutrient contents in soil, However, an open residue burning is still a common practice in Thailand despite of strict law enforcements and proper education to farmers about its implications on soil, human and animal health The present study determined how residues management practices: residue amendment and stubble burning, influence the soil organic carbon by determining δ13C in paddy soil profile. The 30 cm depth soil samples from the naturally straw amendment and stubble burning paddy fields were collected in Chiang Khwan district, Roi-et province during 2017. The δ13C values with soil depth showed that residue management practices produce statistical differences in both soils. The δ13C values of soil samples from amendment and burning sites ranged from-23.19‰ to-17.98‰ and-24.79‰ to-19.28‰, respectively. Carbon isotopes differentiate clearly between amendment site (more positive values) and burning site (more negative values). The results from this study were in accordance with literatures which reported that the δ13C distribution in the soil profile can be applied to study in SOC dynamics as a result of different paddy residue management practices (amendment or burning). Further research is needed to confirm the validity of the stable carbon isotope technique in this type of studies.


2018 ◽  
Author(s):  
Ping Yan ◽  
Hua Peng ◽  
Luobin Yan ◽  
Shaoyun Zhang ◽  
Aimin Chen

Soil pH is the main factor affecting soil nutrient availability and chemical substances in soil. It is of great significance to study the spatial variability of soil pH for soil nutrient management and soil pollution prediction. In order to explore the causes of spatial variability of soil pH in redbed areas, the Nanxiong Basin in south China was selected as an example, and soil pH was measured in the topsoil by nested sampling (0–20 cm depth). The spatial variability characteristics of the soil pH were analysed by geostatistics and classical statistical methods, and the main factors influencing the spatial variability of soil pH are discussed. The results showed that the coefficient of variation in the redbed areas of Nanxiong Basin was 17.18%, indicating moderate variability. The geostatistics analysis showed that the spherical model is the optimal theoretical model for explaining the soil pH’s variability, which is influenced by both structural and random factors. The spatial distribution and pattern analysis showed that soil pH content in the northeast and southwest is relatively high, and is lower in the northwest. These results indicate that topographic factors and land use patterns are the main factors.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Yared Mulat ◽  
Kibebew Kibret ◽  
Bobe Bedadi ◽  
Muktar Mohammed

Abstract Background Soil quality, which can be inferred using indicators that interact synergistically, is affected by land use types and agricultural management practices. This study assessed the status of soil quality under three adjacent land uses (cultivated, grazing, and fallow) in Kersa subwatershed (622 ha). Soil samples were collected from the surface soil (0–20 cm depth) of the identified land uses with three replications and the soil quality parameters were analyzed. A minimum data set of soil quality indicators were selected from physical, chemical, and biological parameters using the literature review and expert opinion method. Linear scoring functions were used to give the unitless scores for the selected data sets, which were then integrated into a soil quality index (SQI). Results The results revealed that bulk density, aggregate stability, pH, cation exchange capacity (CEC), available P, and soil organic carbon (SOC) had a significant difference in SQI among the different land uses. The soil quality indices were 0.69 for grazing land, 0.62 for cultivated land, and 0.59 for the fallow land. The SQI of all the land uses falls in the intermediate soil quality (0.55 < SQI < 0.70) class. Conclusion In almost all the quality indicators assessed, the grazing land was superior to the cultivated and fallow lands. Therefore, implementing management practices that enhance soil quality like organic matter-controlled systems is imperative for sustainable agricultural production in the study area.


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