EVALUATING RELATIONSHIPS AMONG SOIL PROPERTIES BY COMPUTER ANALYSIS

1971 ◽  
Vol 51 (1) ◽  
pp. 105-111 ◽  
Author(s):  
J. A. McKEAGUE ◽  
J. H. DAY ◽  
J. A. SHIELDS

Data for 16 measured and seven calculated properties of 461 samples from 115 soils occurring in various parts of Canada were coded, and a correlation analysis was run on the data for various groups of samples. In general, correlations of color value and organic matter were moderately high (|r| > 0.5) and significant, but for 21 Podzol Ae horizons the correlation was very low (r = −0.13) and not significant. Chroma and dithionite Fe were significantly correlated for several groups of samples but not for Podzolic B (spodic) horizons or Bm horizons. Linear regression equations expressing cation exchange capacity and pH-dependent charge as functions of organic matter and other variables fitted the data reasonably well. The danger of generalizing from presumed relationships among soil properties was indicated but, for some groups of samples, useful relationships existed between visible soil properties and properties measured in the laboratory.

2006 ◽  
Vol 86 (1) ◽  
pp. 133-139 ◽  
Author(s):  
Edouard Lemire ◽  
Kate M Taillon ◽  
William H. Hendershot

Controlling soil pH is important to ensure good crop yield. This study was conducted to determine whether the accuracy of the existing Shoemaker-McLean-Pratt (SMP) pH-buffer method could be improved by using the pH-dependent cation exchange capacity curve (CECpd). Soil pH, SMP and CECpd measurements were performed on 18 acid surface horizon soil samples, with textures from sandy loam to clay loam. These soils were incubated with three levels of calcium carbonate for 12 wk, after which the soil pH and the effective cation exchange capacity (CECe) were measured. The correlation coefficient (R2) for the CECpd and CECe curves was 0.96. The main factor affecting the slope of the curves is the soil organic matter content. The increase of CECe in the soil was also found to be directly proportional to the amount of lime applied, regardless of the type of soil. By using the slope of the Qv versus pH curve for each soil and the relationship between CECe and lime application, we were able to determine the lime required to raise the soil pH in water to 6.5. As an alternative to the current practice of using the SMP buffer, we propose that it should be possible to estimate the pH-dependent CEC curve from measurable soil properties (e.g., organic matter) and to estimate the lime requirement as the difference in CECpd between the existing and desired pH values. Once the slope of the Qv/pH relationship has been determined or estimated for a soil, the only measurement necessary for calculating lime requirement in subsequent years would be the soil pH. The proposed method would provide lime requirement estimates while decreasing the annual cost of soil analysis. Key words: Lime requirement, cation exchange capacity, Non-Ideal Competitive Adsorption, soil properties, organic matter, Fe oxides


1968 ◽  
Vol 48 (1) ◽  
pp. 53-63 ◽  
Author(s):  
J. S. Clark ◽  
W. E. Nichol

Heating in hydrogen peroxide, dilute oxalic acid, and dilute aluminum oxalate did not change the effective cation exchange capacity (CEC) or the pH-7 CEC of Wyoming bentonite and Alberni clay soil containing excess Al(OH)x. This indicated that treatment of soils with H2O2 to oxidize organic matter and the possible production of oxalates during oxidation did not change the CEC values of the inorganic fraction of soils even if some clay exchange sites were blocked by hydrous oxides of Al.With soils of pH less than approximately 5.4, oxidation of organic matter did not change the effective CECs although the pH-7 CEC values were decreased. Thus, organic matter in acid soils appeared to have little or no effective CEC. Because of this and the negligible effect of H2O2 oxidation on the CEC values of clays, the difference of the pH-7 CEC of soils before and after H2O2 oxidation provided a simple means of estimating the amount of organic pH-dependent CEC in acid soils.The amount of organically derived pH-dependent CEC was determined in a number of soils by means of peroxide oxidation. The technique provided a useful indication of the quantities of sesquioxide–organic matter complexes accumulated in medium- and fine-textured soils.


1976 ◽  
Vol 56 (3) ◽  
pp. 213-221 ◽  
Author(s):  
Y. A. MARTEL ◽  
M. R. LAVERDIERE

The objectives of this work were (1) to determine the relation existing between the organic matter contents of Ap horizons and their respective soil Orders, (Gleysolic and Podzolic), texture, pH and geographic locations in the different thermal regions of Quebec and (2) to determine the role of organic matter and soil texture on the cation exchange properties of the same Ap horizons coming from soils used for forage crops in Quebec. The cation-exchange capacity (CEC), the exchangeable bases and acidity were determined by using 1 N NH4OAC – pH 7. The results showed a variation in the carbon content ranging from 1.4 to 6.9%. The heat units accumulated in each region and the clay contents were correlated with the percentage of carbon and nitrogen. Soil pH and soil Orders (Gleysolic vs. Podzolic) did not seem to affect the organic matter content. The cation-exchange capacity (CEC) ranged from 10.6 to 42.6 meq/100 g soil; 40% of this was attributable to carbon and 32% to clay contents. Simple and multiple regression equations showed that carbon was correlated with the exchangeable acidity, while clay was related to the exchangeable bases. The CEC of organic matter and clay were respectively 161 ± 45 meq/100 g organic matter and 29 ± 6 meq/100 g clay. These values, lower than for Western Canada, reflected the nature of the organic matter that is less developed in Eastern Canada than in the Chernozemic soils; they also showed the effect of the predominant illite mineral found in the clay fractions compared to montmorillonite in Western Canada.


CORD ◽  
1988 ◽  
Vol 4 (01) ◽  
pp. 34
Author(s):  
Doah Dekok Tarigans

This study was conducted to investigate the effects of six co­conut cropping patterns on the soil properties and nutrient element status of coconut leaves. The experiments were carried out from August 1984 to May 1985 in Silang, Cavite, Philippines. Data on‑soil properties and nutrient element starus of coconut leaves were statistically analyzed in Randomized Block Design with three replications. Six cropping patterns in coconut with four species of perennial crops as intercrops, namely: banana, papaya, coffee and pineapple were used in this study. The organic matter, pH and cation exchange capacity of the soils did not differ significantly with cropping pattern although intensively cropped farms tended to have higher organic matter' and cation exchange capacity values. Nitrogen, phosphorus and potassium in the top soil were significantly higher in most intensive intercropped farms, but calcium and magnesium did not vary significantly. Moisture content, waterholding capacity, bulk density and particle density of the soil did not show significant difference with cropping patterns. Likewise, the number of bacteria, fungi and actinomycetes in the soil remained statistically the same. Leaf nitrogen and calcium, in­creased while potassium decreased with intensity of cropping. Phosphorus and magnesium showed no definite trend.


2013 ◽  
Vol 27 (1) ◽  
pp. 57-67 ◽  
Author(s):  
S.E. Obalum ◽  
J. Oppong ◽  
C.A. Igwe ◽  
Y. Watanabe ◽  
M.E. Obi

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.


Solid Earth ◽  
2017 ◽  
Vol 8 (4) ◽  
pp. 827-843 ◽  
Author(s):  
Sunday Adenrele Adeniyi ◽  
Willem Petrus de Clercq ◽  
Adriaan van Niekerk

Abstract. Cocoa agroecosystems are a major land-use type in the tropical rainforest belt of West Africa, reportedly associated with several ecological changes, including soil degradation. This study aims to develop a composite soil degradation assessment index (CSDI) for determining the degradation level of cocoa soils under smallholder agroecosystems of southwestern Nigeria. Plots where natural forests have been converted to cocoa agroecosystems of ages 1–10, 11–40, and 41–80 years, respectively representing young cocoa plantations (YCPs), mature cocoa plantations (MCPs), and senescent cocoa plantations (SCPs), were identified to represent the biological cycle of the cocoa tree. Soil samples were collected at a depth of 0 to 20 cm in each plot and analysed in terms of their physical, chemical, and biological properties. Factor analysis of soil data revealed four major interacting soil degradation processes: decline in soil nutrients, loss of soil organic matter, increase in soil acidity, and the breakdown of soil textural characteristics over time. These processes were represented by eight soil properties (extractable zinc, silt, soil organic matter (SOM), cation exchange capacity (CEC), available phosphorus, total porosity, pH, and clay content). These soil properties were subjected to forward stepwise discriminant analysis (STEPDA), and the result showed that four soil properties (extractable zinc, cation exchange capacity, SOM, and clay content) are the most useful in separating the studied soils into YCP, MCP, and SCP. In this way, we have sufficiently eliminated redundancy in the final selection of soil degradation indicators. Based on these four soil parameters, a CSDI was developed and used to classify selected cocoa soils into three different classes of degradation. The results revealed that 65 % of the selected cocoa farms are moderately degraded, while 18 % have a high degradation status. The numerical value of the CSDI as an objective index of soil degradation under cocoa agroecosystems was statistically validated. The results of this study reveal that soil management should promote activities that help to increase organic matter and reduce Zn deficiency over the cocoa growth cycle. Finally, the newly developed CSDI can provide an early warning of soil degradation processes and help farmers and extension officers to implement rehabilitation practices on degraded cocoa soils.


SOIL ◽  
2016 ◽  
Vol 2 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Alemayehu Adugna ◽  
Assefa Abegaz

Abstract. Land use change can have negative or positive effects on soil quality. Our objective was to assess the effects of land uses changes on the dynamics of selected soil physical and chemical properties. Soil samples were collected from three adjacent soil plots under different land uses, namely forestland, grazing land, and cultivated land at 0–15 cm depth. Changes in soil properties on cultivated and grazing land were computed and compared to forestland, and ANOVA (analysis of variance) was used to test the significance of the changes. Sand and silt proportions, soil organic content, total nitrogen content, acidity, cation exchange capacity, and exchangeable Ca2+ content were higher in forestlands. Exchangeable Mg2+ was highest in grazing land, while clay, available phosphorous, and exchangeable K+ were highest in cultivated land. The percentage changes in sand, clay, soil organic matter, cation exchange capacity, and exchangeable Ca2+ and Mg2+ were higher in cultivated land than in grazing land and forestland. In terms of the relation between soil properties, soil organic matter, total nitrogen, cation exchange capacity, and exchangeable Ca2+ were strongly positively correlated with most of soil properties, while available phosphorous and silt have no significant relationship with any of the other considered soil properties. Clay has a negative correlation with all soil properties. Generally, cultivated land has the least concentration of soil physical and chemical properties except clay and available phosphorous, which suggests an increasing degradation rate in soils of cultivated land. So as to increase soil organic matter and other nutrients in the soil of cultivated land, the integrated implementation of land management through compost, cover crops, manures, minimum tillage, crop rotation, and liming to decrease soil acidity are suggested.


1992 ◽  
Vol 8 (3) ◽  
pp. 329-338 ◽  
Author(s):  
Augustine Onwuegbukiwe Isichei ◽  
Joseph Ikechukwu Muoghalu

ABSTRACTThe effect of tree canopy cover on soil properties was studied over three periods: middry season (January), mid-growth period (August) and peak-growth period (October) in three 1 ha plots in savanna of north-west Nigeria. The objective was to find out whether tree canopies change the nutrient status of the soil under them relative to adjacent grasslands. Soils under tree canopies were found to have significantly higher levels of organic matter, calcium, magnesium, potassium, total exchangeable bases, cation exchange capacity and pH than those in open grasslands. Nitrogen and phosphorus were slightly higher in soils under tree canopies than those in the open grasslands. Trees 7 m and above had more influence on soil properties than smaller trees. Differences in soil properties among the study plots were due to differences in their soil texture. Seasonal trends were observed in organic matter, carbon: nitrogen ratio, cation exchange capacity, phosphorus, calcium, sodium, total exchangeable cations and percentage base saturation.


1969 ◽  
Vol 53 (4) ◽  
pp. 369-373
Author(s):  
M. A. Lugo-López ◽  
Raúl Pérez-Escolar

A study is herein reported where attempts to explain the variability in the cation exchange capacity of Lajas Valley soils in terms of other soil properties were made. The independent variables considered were percentage of particles smaller than 0.002 mm., percentage of organic matter, and the summation of the percentage of particles ranging from 0.05 to 0.002 mm. and smaller than 0.002 mm. The correlation coefficients obtained were 0.44, 0.47 and 0.46 for each respective attempt. Only 19 percent of the variability in cation exchange capacity could be explained on the basis of the percentage of particles smaller than 0.002 mm. in size. Another simple correlation where the percentage of particles between 0.05 mm. and 0.002 mm. was added to the percentage of particles smaller than 0.002 failed to explain satisfactorily any significant additional variability. A multiple correlation including the percentage of organic matter, in addition to the percentage of particles smaller than 0.002 mm. also failed to explain any significant additional variability. This failure is analyzed in view of the different nature of montmorillonitic clays that predominate in Lajas Valley soils.


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