BULK DENSITY EQUATIONS FOR SOUTHERN ALASKA SOILS

1989 ◽  
Vol 69 (1) ◽  
pp. 177-180 ◽  
Author(s):  
E. B. ALEXANDER

A close relationship between organic-carbon content and bulk density was utilized to develop equations for predicting the bulk densities of inorganic soils around the Gulf of Alaska; for example[Formula: see text]where Db is the bulk density (Mg m−3) of fine-earth and OC is the organic carbon content (g kg−1). Adding discrete variables for soil texture (three classes):[Formula: see text]where A is 2.24 for loamy sands, 1.86 for sandy loams, and 1.73 for silt loams. Most of the samples used in developing these equations were from B and C horizons, but they appear to be applicable to other horizons too. They are not valid for (1) horizons with very low organic carbon content (C < 1 g kg−1); (2) organic soils; or (3) disturbed or compacted soils. Coarse fragments (particles > 2 mm) were considered in computing the bulk densities of whole soil horizons, because rock fragments are generally much denser than the bulk fine-earth. Key words: Clod samples, Podzolic soils, Spodosols, organic matter

Soil Research ◽  
2002 ◽  
Vol 40 (5) ◽  
pp. 847 ◽  
Author(s):  
Ravinder Kaur ◽  
Sanjeev Kumar ◽  
H. P. Gurung

Collection of non-destructive soil core samples for determination of bulk densities is costly, difficult, time- consuming, and often impractical. To overcome this difficulty, several attempts have been made in the past to estimate soil bulk densities through pedo-transfer functions (PTFs), requiring soil texture and organic carbon (OC) content data. Although many studies have shown that both organic carbon and texture predominantly determine soil bulk density, a majority of the PTFs developed so far are a function only of organic matter (OM)/OC. In addition, no attempts have been made to test and compare the applicability of these PTFs on an independent soil data set. Thus, through this study efforts have been made not only to develop a robust soil bulk density estimating PTF, based on both soil texture and organic carbon content data, but also to compare its predictive potential with the existing PTFs on an independent soil data set from 4 ecologically diverse micro-watersheds in Almora district of Uttaranchal State in India. Effects of varying levels of soil particle size distributions and/or OC/OM contents on the absolute relative errors associated with these PTFs were also analysed for assessing their applicability to the independent soil data set. Amongst the existing PTFs, Curtis and Post, Adams, Federer, and Huntington-A methods were found to be associated with positive bias or mean errors (ME) and root mean square prediction differences (RMSPD) ranging between 0.10 and 0.38, and between 0.23 and 0.45, respectively, whereas Alexander-A, Alexander-B, Manrique and Jones-A, Manrique and Jones-B, and Rawls methods were found to be associated with negative ME and RMSPD values ranging between -0.08 and -0.15, and 0.18 and 0.23, respectively. In contrast, Bernoux, Huntington-B, and Tomasella and Hodnett-PTFs, with RMSPD values ranging between 0.18 and 0.20, were the only methods associated with little or no bias. However, on comparing the predictive potential of the existing PTFs, in terms of their 1 : 1 relationships between the observed and predicted soil bulk densities and ME and RMSPD values, only Manrique and Jones-B (ME: -0.08; RMSPD: 0.18), Alexander-A (ME: -0.08; RMSPD: 0.19), and Rawls (ME: -0.11; RMSPD: 0.22) methods were observed to give somewhat more realistic soil bulk density estimations. The study revealed very limited predictive potential of the existing PTFs, due to their development on specific soils and/or ecosystems, use of an indirectly computed organic matter (instead of directly measured organic carbon) content as a predictor variable, poor predictive potential of developed regression model(s), and/or subjective errors. In contrast to this, the new soil bulk density estimating PTF was found to be associated with far better 1 : 1 relationship between the observed and predicted soil bulk densities and zero ME (or bias) and lowest (0.15 g/cm3) RMSPD values. The absolute relative errors associated with both the new and the existing soil OC/OM and texture-dependent PTFs were observed to be almost insensitive to the varying levels of silt and clay. However, compared with the existing PTFs, these errors associated with the new PTF were observed to be much more insensitive to the varying levels of OC/OM, thereby indicating the applicability of the new PTF to a wide range of soil types.


2015 ◽  
Vol 66 (3) ◽  
pp. 111-118 ◽  
Author(s):  
Mirosław Kobierski ◽  
Krystyna Kondratowicz-Maciejewska ◽  
Katarzyna Kociniewska

Abstract To assess the soil quality of Phaeozems and Luvisols from Kujawy region (Kujawy-Pomerania Province, Poland), the soil quality indicators such as: content of organic matter and nutrients, as well as bulk density were used. The soils showed similar inherent properties (soil texture, depth to parent material, type of clay) and management practices (tillage, crop rotation, nutrient application). The following properties were determined: bulk density, grain size composition, exchangeable acidity, concentration of available forms of potassium, phosphorus and magnesium, and the content of total organic carbon (TOC) and nitrogen (Nt). The amounts of dissolved organic carbon (DOC) and dissolved nitrogen (DN) were measured in the solution obtained after extraction with 0.004 M CaCl2. The stock of TOCs, Nts and DOCs, and DNs were calculated. The total organic carbon content in surface horizon of Phaeozems was significant higher (13.9-20.1 g·kg-1) than in Ap horizon of Luvisols (8.3-11.0 g·kg-1), which is a consequence of their origin. The stock of organic carbon in Ap horizon fell within 5.89 to 8.49 kg·m2 in Phaeozems and 3.80 to 4.81 kg·m2 in Luvisols. Although Phaeozems demonstrated a significant higher content of TOC, as compared with Luvisols, the amount of dissolved organic carbon was similar in both soil types, which points to a higher share of DOC in the total organic carbon content in Luvisols (up to 17.5% in Et horizon). The amounts of dissolved organic carbon and dissolved nitrogen and their stock do not depend on the type of soils if the management practices are similar.


2019 ◽  
Vol 11 (2) ◽  
pp. 298-303
Author(s):  
Brown Mang ONWUKA ◽  
Emmanuel Adeboye ADESEMUYI

Information about spatial distribution of soil qualities in a given area is a fundamental piece of land surface prerequisites for ecological purposes, agriculture and other land use systems. The utilization of numerical methods to portray soil properties and upgrade objectivity in soil-related decision making, was applied to soil samples collected from soil under the land use systems; excavation site (EX), refuse dump site (RD), forest land (FL), continuously cultivated land (CC) and 4-year bush fallow (4-BF) along Umuahia South LGA of Abia State in south eastern Nigeria. Geostatistical technique was applied to estimate the spatial distribution and produce soil maps for each selected soil properties. Results revealed that excavation site (1.70 Mg m-3) recorded a high bulk density, while the other land use systems had a moderate bulk density. The results showed that refuse dump site had a neutral soil reaction (7.02), slightly acidic reaction was recorded under 4-year bush fallow (6.00) and forest land (5.71). Continuously cultivated land had a moderately acidic soil reaction (5.41) and organic carbon content (1.48%). The result also revealed that forestland (2.97%) and refuse dump site (3.20%) had very high organic carbon content, while excavation site (0.38%) had very low organic carbon content. This study will help land owners/users in terms of choice and adoption of land for different uses in the area.  


2018 ◽  
Vol 53 (4) ◽  
pp. 518-521 ◽  
Author(s):  
Cleber Rech ◽  
Jackson Adriano Albuquerque ◽  
Juliano Corulli Corrêa ◽  
Alvaro Luiz Mafra ◽  
Diego Bortolini

Abstract: The objective of this work was to evaluate the superficial and injected applications of swine slurry and urea to the soil, regarding their effects on the physical properties of a Nitossolo Vermelho distroférrico under a no-tillage system. The treatments were: injected slurry into the groove with a liquid swine slurry injector (LSSI); slurry on surface, applied on the lines by the LSSI kept raised; urea injected by opening the groove with the LSSI and distributed manually; and corn, under no-tillage, as a control. Sowing and the injection of liquid slurry or urea do not modify the organic carbon content, pH, and aggregation, but alter the soil bulk density and porosity in the mobilized line, and increase the macropores.


2008 ◽  
Vol 88 (4) ◽  
pp. 533-541 ◽  
Author(s):  
Hassan Al Majou ◽  
Ary Bruand ◽  
Odile Duval

Most pedotransfer functions (PTF) developed over the past three decades to generate water retention characteristics use soil texture, bulk density and organic carbon content as predictors. Despite the high number of PTFs published, most being class- or continuous-PTFs, the accuracy of prediction remains limited. In this study, we compared the performance of different class- and continuous-PTFs developed with a regional database. Results showed that the use of in situ volumetric water content at field capacity as a predictor led to much better estimation of water retention properties compared with using predictors derived from the texture, or the organic carbon content and bulk density. This was true regardless of the complexity of the PTFs developed. Results also showed that the best prediction quality was achieved by using the in situ volumetric water content at field capacity after stratification by texture. Comparison of in situ volumetric water content at field capacity, with the water retained at different matric potentials as measured in the laboratory, showed field capacity to approximate 100 hPa, whatever the soil texture. Finally, the lack accuracy of PTFs that do not use the in situ volumetric water content at field capacity as predictor did not appear due to the test soils being unrepresentative of the soils used to develop the PTFs, but were instead related to poor correlations between the predictors used and the water retention properties. Key words: Pedotransfer functions, root mean square error, mean error of prediction, standard deviation of prediction, texture, bulk density, organic carbon content


2012 ◽  
Vol 52 (No. 9) ◽  
pp. 387-398 ◽  
Author(s):  
E. Cienciala ◽  
Z. Exnerová ◽  
J. Macků ◽  
V. Henžlík

The aim of this study was to evaluate organic carbon content (SOC) in the surface layers of forest soils in the two Natural Forest Regions situated in Southwest Bohemia, namely Z&aacute;padočesk&aacute; pahorkatina (NFR 6) and Česk&yacute; les (NFR 11). The study is based upon on two consecutive soil sampling campaigns during autumn 2003 and 2004. While the sampling of 2003 was inadequate to estimate bulk density, the consecutive campaign used a defined sample volume to permit an estimation of bulk density and quantification of soil organic carbon (SOC) for soil organic layers and the upper mineral horizon. The total sampling depth was 30 cm including both organic and mineral layer. SOC of organic horizon was on average 1.99 kg&nbsp;C/m<sup>2</sup>. It differed by stand site type ranging from 0.70&nbsp;to 3.04 kg&nbsp;C/m<sup>2</sup>. The organic layer SOC was smallest under beech (1.03 kg&nbsp;C/m<sup>2</sup>), whereas it was higher under pine (2.19 kg&nbsp;C/m<sup>2</sup>) and spruce <br />(2.09 kg&nbsp;C/m<sup>2</sup>). SOC in the mineral layer was in average 7.28 kg&nbsp;C/m<sup>2</sup>. SOC differed significantly by the major tree species and reached 10.6; 5.67 and 7.5 kg&nbsp;C/m<sup>2</sup> for beech, pine and spruce sites, respectively. The average SOC for the total soil layer (0&ndash;30 cm) reached 9.33 kg&nbsp;C/m<sup>2</sup>. The methodological aspects of regional estimation of SOC and the potential of utilization of the national forest inventory program are also discussed.


Author(s):  
João H. Caviglione

ABSTRACT From the 1990s, the demand for soil quality indicators has increased with the agricultural sustainability approaches. The S-index was proposed as an indicator of soil physical quality. The objective was to evaluate the sensitivity of S-index as an indicator of soil physical quality and its correlation with bulk density, organic carbon content, macroporosity, microporosity, total porosity and clay, sand and silt contents, under field conditions in the diversity of the Paraná state. Samples were collected from 21 sites with textures from clay and heavy clay, in the layers of 0-0.1 and 0.1-0.2 m, in soil under native forest and in cultivated soil. Eight soil physical attributes were determined. A soil-water retention curve with six moisture points was fitted and the S-index was calculated for each condition. The Wilcoxon Test showed differences in S-index between soil managements with p-value = 0.0015 in the 0-0.1 m layer and less than 0.0001 in the 0.1-0.2 m layer. The observed S-index showed to be a sensitive indicator of soil physical quality and with a significant Pearson correlation with bulk density (‑0.826), macroporosity (0.760), total porosity (0.836), and organic carbon content (0.583).


Soil Research ◽  
2006 ◽  
Vol 44 (5) ◽  
pp. 487 ◽  
Author(s):  
K. M. Hati ◽  
A. Swarup ◽  
D. Singh ◽  
A. K. Misra ◽  
P. K. Ghosh

Effects of continuous cropping, fertilisation, and manuring on soil organic carbon content and physical properties such as particle size distribution, bulk density, aggregation, porosity, and water retention characteristics of a Typic Ustochrept were examined after 31 cycles of maize–wheat–cowpea (fodder) crop rotation. Five contrasting nutrient treatments from a long-term fertiliser experiment were chosen for this study: control (no fertiliser or manure); 100% (optimum dose) nitrogen (N) fertiliser; 100% nitrogen and phosphorus (NP); 100% nitrogen, phosphorus, and potassium (NPK); 100% NPK + farmyard manure (NPK+FYM). The NPK+FYM treatment significantly improved soil organic carbon (SOC) content in 0–0.15 m soil compared with the other 4 treatments; the NPK treatment resulted in significantly more SOC than the control and N treatments (P < 0.05). The SOC in NPK and NPK+FYM treatments was 38.6 and 63.6%, respectively, more than the initial level of SOC (4.4 g/kg) after 31 cycles of cropping. The control and N treatments maintained the SOC status of the soil at the initial value. NPK+FYM significantly improved soil aggregation, soil water retention, microporosity, and available water capacity and reduced bulk density of the soil at 0–0.30 m depth. Greater crop growth under the NPK treatment resulted in increased organic matter content of soil, which improved aggregate stability, water retention capacity, and microporosity compared with the control. The effects were more conspicuous with the NPK+FYM treatment and at the surface soil (0–0.15 m). Application of imbalanced inorganic fertiliser (N and NP treatments) did not have a deleterious effect on the physical properties of the soil compared with the control. SOC content showed a highly significant and positive correlation with mean weight diameter (0.60), % water-stable macro-aggregates (0.61), and soil water retention at –0.033 MPa (0.75) and –1.5 MPa (0.72), and negative correlation with bulk density (–0.70) for the surface 0–0.15 m soil. The study thus suggests that application of balanced mineral fertilisers in combination with organic manure sustains a better soil physical environment and higher crop productivity under intensive cultivation.


2020 ◽  
Author(s):  
Gülay Karahan ◽  
Seongyun Kim ◽  
Yakov Pachepsky

&lt;p&gt;Infiltration is strongly affected by soil structure. The measurement technique and the land use are two soil structure-related attributes that are typically available in descriptions of infiltration experiments. We hypothesized that these attributes may be good predictors of the performance of different infiltration models, and of the parameter values in those models. The international soil infiltration database SWIG assembled in the Institute of Agrosphere in J&amp;#252;lich, Germany, was used as the data source. The database encompasses about 5000 experiments all over the world, Texture, measurement method and land use were known for all experiments, availability of organic carbon content, bulk density, saturated hydraulic conductivity (Ksat), pH, the electrical conductivity of saturated paste, and initial water content varied. Comparison of the performance of eight infiltration models showed that Horton and Mezencev models outperformed all others and that one of these two models could be preferred based on the infiltration measurement method. The machine learning method &amp;#8211; regression trees &amp;#8211; was applied to find the most influential predictors of parameters of Horton and Mezencev models. The measurement method, the textural class, and the land use were the most influential predictors in 80% of cases for both models. The measurement method was the most influential input in 40% of cases. The accuracy of parameter estimates increased when only the subset of measurements with the same method was used to estimate infiltration parameters. Land use, textural class, and organic carbon content dominated as the most influential predictors for the parameters of the Mezencev model, whereas land use, textural class, Ksat, and bulk density became most important in the case of the Horton model. Overall, estimates of the infiltration equation parameters can be more accurate if they have been developed for the same measurement method as in the task in hand. Land use category and the infiltration measurement method provide useful surrogate information about the soil structure effect on infiltration.&amp;#160;&lt;/p&gt;


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