scholarly journals Spatial variability and mapping of soil fertility status in a high-potential smallholder farming area under sub-humid conditions in Zimbabwe

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Gabriel Soropa ◽  
Olton M. Mbisva ◽  
Justice Nyamangara ◽  
Ermson Z. Nyakatawa ◽  
Newton Nyapwere ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Soil Properties ◽  
Soil Ph ◽  
Strong Evidence ◽  
Spatial Dependence ◽  
Random Component ◽  
Smallholder Farming ◽  
Mineral N ◽  
Spatial Trend ◽  
Spatial Trends

AbstractA study was conducted to examine spatial variability of soil properties related to fertility in maize fields across varying soil types in ward 10 of Hurungwe district, Zimbabwe; a smallholder farming area with sub-humid conditions and high yield potential. Purposively collected and geo-referenced soil samples were analyzed for texture, pH, soil organic carbon (OC), mineral N, bicarbonate P, and exchangeable K. Linear mixed model was used to analyze spatial variation of the data. The model allowed prediction of soil properties at unsampled sites by the empirical best linear unbiased predictor (EBLUP). Evidence for spatial dependence in the random component of the model was evaluated by calculating Akaike’s information criterion. Soil pH ranged from 4.0 to 6.9 and showed a strong spatial trend increasing from north to south, strong evidence for a difference between the home and outfields with homefields significantly higher and between soil textural classes with the sand clay loam fraction generally higher. Soil OC ranged from 0.2 to 2.02% and showed no spatial trend, but there was strong evidence for a difference between home and outfields, with mean soil OC in homefields significantly larger, and between soil textural classes, with soil OC largest in the sandy clay loams. Both soil pH and OC showed evidence for spatial dependence in the random effect, providing a basis for spatial prediction by the EBLUP, which was presented as a map. There were significant spatial trends in mineral N, available P and exchangeable K, all increasing from north to south; significant differences between homefields and outfields (larger concentrations in homefields), and differences between the soil textural classes with larger concentrations in the sandy clay loams. However, there was no evidence for spatial dependence in the random component, so no attempt was made to map these variables. These results show how management (home fields vs outfields), basic soil properties (texture) and other factors emerging as spatial trends influence key soil properties that determine soil fertility in these conditions. This implies that the best management practices may vary spatially, and that site-specific management is a desirable goal in conditions such as those which apply in Ward 10 of Hurungwe district in Zimbabwe.

Spatial variability of uncultivated soils in derived savanna

2013 ◽  
Vol 27 (1) ◽  
pp. 57-67 ◽  
Author(s):  
S.E. Obalum ◽  
J. Oppong ◽  
C.A. Igwe ◽  
Y. Watanabe ◽  
M.E. Obi
Keyword(s):  
Organic Matter ◽  
Spatial Variability ◽  
Soil Properties ◽  
Cation Exchange ◽  
Soil Ph ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Organic Matter Concentration ◽  
Derived Savanna ◽  
Matter Concentration

Abstract The spatial variability of some physicochemical properties of topsoils/subsoils under secondary forest, grassland fallow, and bare-soil fallow of three locations was evaluated. The data were analyzed and described using classical statistical parameters. Based on the coefficient of variation, bulk density, total porosity, 60-cm-tension moisture content, and soil pH were of low variability. Coarse and fine sand were of moderate variability. Highly variable soil properties included silt, clay, macroporosity, saturated hydraulic conductivity, organic matter concentration, and cation exchange capacity. Overall, soil pH and silt varied the least and the most, respectively. Relative weighting showed that location dominantly influenced the soil variability, except for soil porosity and organic matter concentration influenced mostly by land use. Most of the soil data were normally distributed; others were positively skewed and/or kurtotic. The minimum number of samples (at 25 samples ha-1) required to estimate mean values of soil properties was highly soil property-specific, ranging from 1 (topsoil pH-H2O) to 246 (topsoil silt). Cation exchange capacity of subsoils related fairly strongly with cation exchange capacity of topsoils (R2 = 0.63). Spatial variability data can be used to extrapolate dynamic soil properties across a derived-savanna landscape.

Spatial heterogeneity of soil physico-chemical properties in contrasting wetland soils in two agro-ecological zones of Lesotho

Soil Research ◽  
2012 ◽  
Vol 50 (7) ◽  
pp. 579 ◽  
Author(s):  
T. Nkheloane ◽  
A. O. Olaleye ◽  
R. Mating
Keyword(s):  
Spatial Variability ◽  
Spatial Heterogeneity ◽  
Soil Properties ◽  
Spatial Dependence ◽  
Chemical Properties ◽  
Stepwise Multiple Regression ◽  
Available Phosphorus ◽  
Ecological Zones ◽  
Physico Chemical ◽  
Agro Ecological Zones

Wetlands are complex ecosystems, often exhibiting considerable spatial variability, making the understanding of soil spatial relationships within them difficult. A study was conducted to evaluate spatial variability of soil physico-chemical properties in two contrasting wetlands in two agro-ecological zones (AEZs) of Lesotho. Soil samples were collected along two transects in mini-pits dug at different depths at 50-m intervals. The collected samples were analysed for particle size, pH, soil organic carbon (SOC), SOC pool, available phosphorus (Av-P), cation exchange capacity (CEC), and base cations. Results showed that within-site variability was very low for sand particles and pH (coefficient of variation <15% for both properties). Soil physical properties generally showed less spatial heterogeneity than chemical properties, which differed widely within and between the study sites. There was generally low correlation between soil properties, and SOC accounted for most of the variation observed at both sites, especially T’sakholo with partial R2 = 94%; at Thaba-Putsoa, partial R2 = 44%. Geostatistical analysis showed that all of the nugget to sill ratios (NSR) showed strong spatial dependence (i.e. NSR of 54–94%) except SOC (T’sakholo stream-bank) with no spatial dependence, with the nugget accounting for 23.43%. We therefore conclude that further wetland studies in Lesotho should attempt to quantify not only the soil properties or processes under investigation but also their spatial variability, because this spatial variability can provide insight into underlying ecosystem processes and may itself indicate wetland condition. In addition, results of stepwise multiple regression showed that SOC and texture could be used across these sites for the sustainable management of these wetlands.

scholarly journals Spatial and temporal variability of Eh and pH over a rice field as related to lime addition

Bragantia ◽  
2010 ◽  
Vol 69 (suppl) ◽  
pp. 67-76 ◽  
Author(s):  
Luis Alberto Morales ◽  
Jorge Paz-Ferreiro ◽  
Sidney Rosa Vieira ◽  
Eva Vidal Vázquez
Keyword(s):  
Spatial Variability ◽  
Soil Ph ◽  
Spatial Dependence ◽  
Temporal Stability ◽  
Small Scale ◽  
Spatial And Temporal Variability ◽  
Data Sets ◽  
Contour Maps ◽  
Semivariogram Analysis ◽  
Spherical Models

The aim of this study was to describe the effect of lime additions on the spatial variability of pH and Eh in a typic Plintacualf cultivated with rice, in Corrientes, Argentina. The 5.1 ha field was divided in three sub plots at which dolomitic lime additions were made at the rates zero, 625 kg ha-1 and 1250 kg ha-1. The soil was sampled at three stages: before sowing thus in aerobic conditions, and then two more times in anaerobiosis. Ninety-six samples per sub plot were taken on each of the three sampling stages on a grid of 11.9 x 20 m. Soil pH and Eh were measured by routine methods. The pH values increased, whereas Eh values decreased, following flooding. The coefficients of variation for pH was rather low during all the three studied periods. Conversely, the CV values for Eh were initially low but with a sharp increased in the second sampling date. The spatial variability of the studied soil properties was assessed using semivariogram analysis and examination of the maps constructed with values interpolated with kriging. Soil pH exhibited a rather strong spatial dependence, whereas soil Eh had a strong to moderate spatial dependence all over the three studied periods and for the three lime rates. Spherical models reaching a stable sill with low to moderate nugget effect were fitted to the experimental semivariograms for the 18 data sets (3 subplots, 3 liming rates and 2 properties) studied. Spatial variability of pH and Eh on rice fields was far from negligible both on aerobic and on anaerobic conditions. In general pH exhibited a stronger spatial dependence than Eh and also showed a tendency to present smaller ranges of spatial dependence. Contour maps clearly showed the presence of small scale variability for pH and Eh within each liming treatment and during each of the three sampling dates. Neither pH or Eh had temporal stability of the pattern of spatial distribution on field studied.

Spatial variability of some chemical properties of a Cambisol soil with cocoa (Theobroma cacao L.) cultivation

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Sergio Salgado García ◽  
Joana Acopa Colorado ◽  
Sergio Salgado-Velázquez ◽  
Samuel Córdova Sánchez ◽  
David Palma López ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Soil Properties ◽  
Spatial Dependence ◽  
Chemical Properties ◽  
Kriging Interpolation ◽  
Management Zones ◽  
Agronomic Management ◽  
Management Area ◽  
Theobroma Cacao L ◽  
Exchangeable P

Objective: To evaluate the spatial variability of some chemical properties of a Cambisolsoil, in order to establish specific agronomic management zones for cocoa cultivation.Methodology: A sampling of 42 georeferenced points equidistant at 40 m was carriedout. Geostatistical variability maps were made with the results of the chemical analysisof the soil properties, using the ordinary Kriging interpolation technique.Results: It was found that the percentage of saturation of acidity (PSA), acidity and H+showed high variability; P-Olsen and interchangeable K, Ca and Mg displayed mediumvariability, and pH, MO, CIC and Al presented low variability. Soil properties pH, PSA;Exchangeable P-Olsen, Ca and Mg showed high spatial dependence (&lt;25%) and OM,exchangeable K and CIC moderate spatial dependence (25-75%).Study limitations / Implications: The generated maps allowed the identification ofpartial areas with different variability, as well as the direction of greatest variability of theproperty as a function of distance.Conclusions: With the maps, it was possible to make recommendations for agronomicmanagement depending on each specific management area.

GENERAL AND SPATIAL VARIABILITY OF SOLONETZIC SOILS IN NORTH CENTRAL ALBERTA

1985 ◽  
Vol 65 (1) ◽  
pp. 157-167 ◽  
Author(s):  
M. R. CARTER ◽  
J. R. PEAREN
Keyword(s):  
Spatial Variability ◽  
Soil Properties ◽  
Spatial Dependence ◽  
Periodic Variation ◽  
Local Area ◽  
Soil Sampling ◽  
North Central ◽  
Solonetzic Soil ◽  
Ap Horizon ◽  
Soil Variation

The general and spatial variation of several soil profile chracteristics, and properties of agronomic and ameliorative importance, were determined on a regional and local area of Solonetzic soil in north central Alberta. Differences in general variation as characterized by the mean, median, coefficient of variation (CV), and range allowed grouping of soil properties according to high (e.g. EC in the Ap horizon), medium and low (e.g. pH of the Ap horizon) variation. Such grouping, along with specific differences in soil variation between the regional and local area was associated with the saline-sodic characteristics of these Solonetzic soils. Spatial variability was studied using a geostatistical method (variograms) on soil samples obtained from a 5-m grid. The variograms for most of the various soil properties did not reveal strong spatial dependence. Large nugget variances accounted for 60–90% of the total variance. The semivariance approximated the overall variance usually within 10 m. Variograms suggested periodic variation for the pH and EC of the Ap horizon. Extractable Ca in the Bnt horizon and the depth of the Ap and Bnt horizons were anisotropic showing significant spatial dependence with direction of sampling. The implication of soil variability in regard to soil sampling is discussed. Key words: Spatial variability, Solonetzic soil, saline-sodic soil, soil sampling, variogram

scholarly journals Assessment of Spatial Variability in Soil Properties of Nagalvadi Micro-Watershed using Geospatial Techniques for Site-Specific Agricultural Input Management in Wardha District of Maharashtra

Agropedology ◽  
2019 ◽  
Vol 27 (2) ◽  
Author(s):  
Nilima S. Sadanshiv ◽  
◽  
M.S.S. Nagaraju ◽  
J.D. Giri ◽  
Rajeev Srivastava ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Organic Carbon ◽  
Spatial Variability ◽  
Soil Properties ◽  
Spatial Dependence ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Moisture Retention ◽  
Available N ◽  
Soil Moisture Retention

Soil sampling at many sites is costly and time consuming and hence warrants for predicting the soil properties at un-sampled location from sampled site using spatial dependence characteristics of soil properties through interpolation with reasonable accuracy. Soil samples (0 to 20 cm depth) were collected from a regular grid of 200 by 200 m from Nagalvadi micro-watershed of Wardha district, Maharashtra and analyzed for sand, silt, clay, bulk density, pH, organic carbon, cation exchange capacity, soil moisture retention at -33 kPa and -1500 kPa, available N, P, K and micronutrient cations. Soil thematic maps were generated using semivariogram analysis and ordinary kriging. Spatial variability in soil properties indicated that sand, silt, clay, bulk density, organic carbon, cation exchange capacity, moisture retention at -33 kPa, available N, Fe, and Zn have displayed moderate spatial dependence, whereas, soil pH and available Mn showed strong spatial dependence. Soil organic carbon and soil moisture retention at -33 kPa were spatially correlated for a short range. The kriged maps of soil properties and soil fertility generated are useful for better management decisions.

scholarly journals Spatial Variability of Soil Nutrients and Their Relationship in Semi-Arid Uplands of Southern India

Agropedology ◽  
2019 ◽  
Vol 29 (2) ◽  
Author(s):  
B. Kalaiselvi ◽  
◽  
S. Dharumarajan ◽  
M. Lalitha ◽  
R. Srinivasan ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Spatial Variability ◽  
Soil Ph ◽  
Spatial Dependence ◽  
Tamil Nadu ◽  
Southern India ◽  
Available P ◽  
Moderate Degree ◽  
Circular Model ◽  
Semi Arid

A study was conducted to determine the spatial variability pH, electrical conductivity, organic carbon, available macro and micronutrients in Palani block, Dindigul district representing Tamil Nadu uplands of semi-arid southern India. A total of 119 geo-referenced surface soil samples were collected based on landscape ecological units. The soils varied from very strongly acidic (pH-4.57) to strongly alkaline (pH-8.74) and were non-saline (EC <0.60 dSm-1). Soil pH had lowest coefficient of variation (17 %), whereas, other parameters possessed highest co-efficient of variation. Experimental semi-variograms were fitted for different models like circular, spherical, exponential, Gaussian and stable. Among the models, exponential model was best fitted for pH, OC, available P, Fe and Mn, Circular model for available K and EC and Gaussian model for Cu and Zn using weighted least square. The models with minimal RMSE are considered as the best cross-validation results. Experimental semi-variogram (Nugget-sill ratio) indicated a moderate degree of spatial dependence (0.25-0.75) for EC, soil organic carbon, available P and K, and strong degree of spatial dependence (<0.25) for soil pH, available Iron, Copper, Manganese and Zinc. The present study suggests that the geo-statistical model can reveal the spatial variability of soil properties and will help farmers and decision makers for sustainable management.

Effect of Slope Mesorelief on the Spatial Variability of Soil Properties and Vegetation Index Based on Remote Sensing Data

2019 ◽  
Vol 55 (9) ◽  
pp. 1329-1337
Author(s):  
N. V. Gopp ◽  
T. V. Nechaeva ◽  
O. A. Savenkov ◽  
N. V. Smirnova ◽  
V. V. Smirnov
Keyword(s):  
Remote Sensing ◽  
Spatial Variability ◽  
Soil Properties ◽  
Vegetation Index ◽  
Remote Sensing Data ◽  
Sensing Data

Spatial Variability of Rainfed Wheat Production Under the Influence of Topography and Soil Properties in Loess-Derived Soils, Northern Iran

2020 ◽  
Vol 14 (4) ◽  
pp. 597-608
Author(s):  
Mohammad Ajami ◽  
Ahmad Heidari ◽  
Farhad Khormali ◽  
Mojtaba Zeraatpisheh ◽  
Manouchehr Gorji ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Soil Properties ◽  
Northern Iran ◽  
Wheat Production ◽  
Rainfed Wheat
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