Spatial variability of soil porosity under reduced tillage in a Humo-Ferric Podzol

1995 ◽  
Vol 75 (1) ◽  
pp. 149-152 ◽  
Author(s):  
M. R. Carter
Keyword(s):  
Bulk Density ◽  
Prince Edward Island ◽  
Pore Space ◽  
Soil Bulk Density ◽  
Soil Sampling ◽  
Moisture Regime ◽  
Humid Climate ◽  
Soil Moisture Regime ◽  
Classical Statistics ◽  
Water Filled Pore Space

The spatial and random variability of soil bulk density, water-filled pore space and macroporosity, which are important indices of soil physical quality in a humid soil moisture regime, were studied in soil samples taken from direct-drilled rotations at Charlottetown, Prince Edward Island. Classical statistics indicated variation was low for bulk density (CV = 3.0–5.8%) and water-filled pore space (CV = 7.4–10.3%), and medium (CV = 15.7–29.6%) for macropore volume. Spatial variation determined using variograms indicated some degree of spatial structure. The ability of variograms to divide sample variance into random and spatial components allows improved estimation of soil sampling size and spacing. Key words: Geostatistics, soil sampling, direct-drilling, humid climate

RELATIVE MEASURES OF SOIL BULK DENSITY TO CHARACTERIZE COMPACTION IN TILLAGE STUDIES ON FINE SANDY LOAMS

1990 ◽  
Vol 70 (3) ◽  
pp. 425-433 ◽  
Author(s):  
M. R. CARTER
Keyword(s):  
Grain Yield ◽  
Bulk Density ◽  
Soil Compaction ◽  
Sandy Loam ◽  
Soil Bulk Density ◽  
Moisture Regime ◽  
Density Level ◽  
Soil Consolidation ◽  
Fine Sandy Loam ◽  
Relative Compaction

Field studies concerned with soil physical properties require methods to quantify and characterize soil compaction, especially for tillage experiments. The bulk densities of a Charlottetown and Gowanbrae fine sandy loam were related to a maximum or standard compaction state for each soil to obtain a measure of relative compaction. The two soils were both classified as Orthic Humo-Ferric Podzols. Relative compaction was closely related to the volume of macropores (r2 = 0.85). Over a 3-yr period, mouldboard ploughing loosened the soil to give an average relative compaction of 77%. Subsequent soil consolidation and settling increased relative compaction to 84% over the growing season. Direct-drilling maintained relative compaction at a limited range of 88–91%. Relative grain yield of cereals was related (r2 = 0.69) using a polynomial curve to relative compaction. A range of 77–84% relative compaction was associated with a relative grain yield ≥ 95%. A relative compaction of 84–89% was considered the equilibrium soil density level for the two soils under study. This range was related to a macropore volume of 13.5–10% which is adequate for permeability but possibly inadequate for optimum soil aeration under a humid soil moisture regime. Overall, relative compaction provided a useful index or standard to assess changes in soil bulk density and proved to be a biologically meaningful soil physical parameter. Key words: Soil compaction indices, relative compaction, Podzolic soil, fine sandy loam, cereal yield

scholarly journals Estimation of the density of the clay-organic complex in soil

2016 ◽  
Vol 30 (1) ◽  
pp. 19-23 ◽  
Author(s):  
Ewa A. Czyż ◽  
Anthony R. Dexter
Keyword(s):  
Organic Matter ◽  
Bulk Density ◽  
Pore Space ◽  
Organic Matter Content ◽  
Soil Bulk Density ◽  
Matter Content ◽  
Gas Content ◽  
Effective Density ◽  
Organic Complex ◽  
Arable Soils

Abstract Soil bulk density was investigated as a function of soil contents of clay and organic matter in arable agricultural soils at a range of locations. The contents of clay and organic matter were used in an algorithmic procedure to calculate the amounts of clay-organic complex in the soils. Values of soil bulk density as a function of soil organic matter content were used to estimate the amount of pore space occupied by unit amount of complex. These estimations show that the effective density of the clay-organic matter complex is very low with a mean value of 0.17 ± 0.04 g ml−1 in arable soils. This value is much smaller than the soil bulk density and smaller than any of the other components of the soil considered separately (with the exception of the gas content). This low value suggests that the clay-soil complex has an extremely porous and open structure. When the complex is considered as a separate phase in soil, it can account for the observed reduction of bulk density with increasing content of organic matter.

scholarly journals Silage-corn harvesting machinery traffic effects on soil bulk density and water permeability

2013 ◽  
Vol 59 (No. 4) ◽  
pp. 136-140
Author(s):  
I. Ahmadi ◽  
H. Ghaur
Keyword(s):  
Bulk Density ◽  
Water Permeability ◽  
Soil Compaction ◽  
Field Experiments ◽  
Soil Bulk Density ◽  
Soil Sampling ◽  
Soil Porosity ◽  
Silty Clay ◽  
Water Permeability Coefficient ◽  
Loam Soil

Soil compaction caused by machinery traffic affects the growth of agricultural crops and also has environmental effects like soil damage and erosion. Field experiments were conducted to study the effects of repeated silage-corn harvesting machinery traffic on dry soil bulk density and porosity variations at three different sampling depths, moreover average water permeability coefficient of the examined silty clay loam soil was measured using the falling head method of water permeability test. The examined treatments which were applied while harvesting silage-corn with the combination of tractor, chopper and truck were the number of traffic passes and depths of soil sampling. Significant differences between soil compaction treatments were observed in bulk density and porosity of soil. Numerically, 22% increase in soil bulk density and 19% reduction in soil porosity were recorded due to the effect of two passes of the examined machineries over the field terrain comparing to the non-traffic treatment. Moreover; soil sampling at 0–10 cm and 20–30 cm depths resulted in the highest and the lowest soil porosity respectively.

scholarly journals Estimating soil water retention for wide ranges of pressure head and bulk density based on a fractional bulk density concept

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Huihui Sun ◽  
Jaehoon Lee ◽  
Xijuan Chen ◽  
Jie Zhuang
Keyword(s):  
Water Content ◽  
Bulk Density ◽  
Soil Water ◽  
Water Retention ◽  
Pore Space ◽  
Pressure Head ◽  
Soil Bulk Density ◽  
Residual Water ◽  
Soil Water Retention ◽  
Residual Water Content

Abstract Soil water retention determines plant water availability and contaminant transport processes in the subsurface environment. However, it is usually difficult to measure soil water retention characteristics. In this study, an analytical model based on a fractional bulk density (FBD) concept was presented for estimating soil water retention curves. The concept allows partitioning of soil pore space according to the relative contribution of certain size fractions of particles to the change in total pore space. The input parameters of the model are particle size distribution (PSD), bulk density, and residual water content at water pressure head of 15,000 cm. The model was tested on 30 sets of water retention data obtained from various types of soils that cover wide ranges of soil texture from clay to sand and soil bulk density from 0.33 g/cm3 to 1.65 g/cm3. Results showed that the FBD model was effective for all soil textures and bulk densities. The estimation was more sensitive to the changes in soil bulk density and residual water content than PSD parameters. The proposed model provides an easy way to evaluate the impacts of soil bulk density on water conservation in soils that are manipulated by mechanical operation.

scholarly journals Uncertainties in the prediction of spatial variability of soil CO2 emissions and related properties

2012 ◽  
Vol 36 (5) ◽  
pp. 1466-1475 ◽  
Author(s):  
Daniel De Bortoli Teixeira ◽  
Elton da Silva Bicalho ◽  
Alan Rodrigo Panosso ◽  
Luciano Ito Perillo ◽  
Juliano Luciani Iamaguti ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Respiration ◽  
Spatial Variability ◽  
Bulk Density ◽  
Ordinary Kriging ◽  
Co2 Emission ◽  
Pore Space ◽  
Soil Bulk Density ◽  
Soil Co2 ◽  
Soil Co2 Emission

The soil CO2 emission has high spatial variability because it depends strongly on soil properties. The purpose of this study was to (i) characterize the spatial variability of soil respiration and related properties, (ii) evaluate the accuracy of results of the ordinary kriging method and sequential Gaussian simulation, and (iii) evaluate the uncertainty in predicting the spatial variability of soil CO2 emission and other properties using sequential Gaussian simulations. The study was conducted in a sugarcane area, using a regular sampling grid with 141 points, where soil CO2 emission, soil temperature, air-filled pore space, soil organic matter and soil bulk density were evaluated. All variables showed spatial dependence structure. The soil CO2 emission was positively correlated with organic matter (r = 0.25, p < 0.05) and air-filled pore space (r = 0.27, p < 0.01) and negatively with soil bulk density (r = -0.41, p < 0.01). However, when the estimated spatial values were considered, the air-filled pore space was the variable mainly responsible for the spatial characteristics of soil respiration, with a correlation of 0.26 (p < 0.01). For all variables, individual simulations represented the cumulative distribution functions and variograms better than ordinary kriging and E-type estimates. The greatest uncertainties in predicting soil CO2 emission were associated with areas with the highest estimated values, which produced estimates from 0.18 to 1.85 t CO2 ha-1, according to the different scenarios considered. The knowledge of the uncertainties generated by the different scenarios can be used in inventories of greenhouse gases, to provide conservative estimates of the potential emission of these gases.

scholarly journals Growth of Bedding Plants in Sphagnum Peat and Coir Dust-Based Substrates

1996 ◽  
Vol 14 (4) ◽  
pp. 187-190 ◽  
Author(s):  
Michael R. Evans ◽  
Robert H. Stamps
Keyword(s):  
Bulk Density ◽  
Pore Space ◽  
Fresh Weight ◽  
Axillary Shoots ◽  
Bedding Plants ◽  
Sphagnum Peat ◽  
Bright Yellow ◽  
Water Filled Pore Space ◽  
Coir Dust ◽  
Water Holding

Abstract Water-holding capacity of substrates increased as the proportion of sphagnum peat and coir increased, and coir-based substrates had greater water-holding capacities than comparable peat-based substrates. There were no significant differences between coir and peat-based substrates with respect to bulk density, percent pore space and percent solids. Air-filled pore space and water-filled pore space decreased and increased, respectively, as the proportion of peat and coir increased. ‘Pink Elite’ geranium plants grown in coir-based substrates had greater root fresh weights than those grown in sphagnum-peat based substrates. Greatest root fresh weight occurred in an 80% coir and 20% perlite substrate. Days to flower, height, shoot fresh weight and number of axillary shoots were not significantly different between substrates. ‘Janie Bright Yellow’ marigold and ‘Blue Lace Carpet’ petunia plants had increased heights and shoot fresh weights when grown in coir-based substrates as compared with sphagnum peat-based substrates. Greatest heights and shoot fresh weights of petunia and marigold occurred in an 80% coir and 20% perlite substrate. Days to flower were reduced for marigold plants grown in coir-based substrates.

Evaluation of soil sampling schemes for geostatistical analyses: A case study for soil bulk density

1991 ◽  
Vol 71 (2) ◽  
pp. 165-176 ◽  
Author(s):  
T. Entz ◽  
C. Chang
Keyword(s):  
Bulk Density ◽  
Random Sampling ◽  
Soil Bulk Density ◽  
Soil Sampling ◽  
Sampling Scheme ◽  
Density Estimates ◽  
Density Measurements ◽  
Grid Sampling ◽  
Sampling Schemes

Sixteen soil sampling schemes were evaluated in a case study using geostatistical analyses to determine their impact on directional sample variograms and kriging. Soil bulk density measurements for each sampling scheme were obtained from an intensively sampled grid, and kriging was used to estimate the bulk densities not included in the sampling scheme. The kriged bulk density estimates for all sampling schemes were verified using a minimum of 6168 observed values. Grid sampling for this study required more samples than stratified random sampling and the stratified-grid sampling schemes, but the accuracy of the kriged estimates was comparable for all sampling schemes. Key words: Kriging, variogram, soil density

Effects of soil modification and treading on pasture growth and physical properties of an irrigated red-brown earth

1985 ◽  
Vol 36 (6) ◽  
pp. 799 ◽  
Author(s):  
KB Kelly
Keyword(s):  
Bulk Density ◽  
Soil Profile ◽  
Surface Soil ◽  
Pore Space ◽  
Cumulative Effect ◽  
Soil Bulk Density ◽  
Pasture Production ◽  
Profile Modification ◽  
Penetrometer Resistance ◽  
Normal Soil

Lemnos loam, a red-brown earth used extensively for pasture production in northern Victoria, and its exposed subsoil (topsoil removed) were both subjected to surface cultivation and total profile modification. Total profile modification consisted of excavating and mixing the top 1.1 m of soil and incorporating gypsum (10 t ha-1), superphosphate (4.5 t ha-1) and ammonium nitrate (0.5 t ha-1) . A white clover-perennial ryegrass pasture was established. Treading by cattle was superimposed over these soil treatments. Exposure of the subsoil, as often occurs with laser landforming, reduced pasture growth by 30% compared with a normal soil profile. Modification of the exposed subsoil negated this effect. Modification of the normal soil profile had little effect on pasture production but did influence pasture composition. Treading had a cumulative effect with time, reducing pasture production by 6, 9 and 12% in 1981, 1982 and 1983, respectively. This occurred despite the precaution of allowing grazing only when the soil was dry. Profile modification resulted in increased pore space and root growth, and lowered bulk density and penetrometer resistance at depth. Treading increased surface soil bulk density, with penetrometer studies showing that this effect was confined to the top 0.15 m.

MEASUREMENT AND PALEOCLIMATIC SIGNIFICANCE OF SOIL BULK DENSITY FOR LOESS IN EXTREME ARID REGION

2010 ◽  
Vol 30 (2) ◽  
pp. 127-132
Author(s):  
Jinbo ZAN ◽  
Shengli YANG ◽  
Xiaomin FANG ◽  
Xiangyu LI ◽  
Yibo YANG ◽  
...  
Keyword(s):  
Bulk Density ◽  
Arid Region ◽  
Soil Bulk Density ◽  
Paleoclimatic Significance
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