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

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

2011 ◽  
Vol 91 (6) ◽  
pp. 957-964 ◽  
Author(s):  
C. Halde ◽  
A. M. Hammermeister ◽  
N. L. Mclean ◽  
K. T. Webb ◽  
R. C. Martin

Halde, C., Hammermeister, A. M., McLean, N. L., Webb, K. T. and Martin, R. C. 2011. Soil compaction under varying rest periods and levels of mechanical disturbance in a rotational grazing system. Can. J. Soil Sci. 91: 957–964. In Atlantic Canada, data are limited regarding the effect of grazing systems on soil compaction. The objective of the study was to determine the effect of intensive and extensive rotational pasture management treatments on soil bulk density, soil penetration resistance, forage productivity and litter accumulation. The study was conducted on a fine sandy loam pasture in Truro, Nova Scotia. Each of the eight paddocks was divided into three rotational pasture management treatments: intensive, semi-intensive and extensive. Mowing and clipping were more frequent in the intensive than in the semi-intensive treatment. In the extensive treatment, by virtue of grazing in alternate rotations, the rest period was doubled than that of the intensive and semi-intensive treatments. Both soil bulk density (0–5 cm) and penetration resistance (0–25.5 cm) were significantly higher in the intensive treatment than in the extensive treatment, for all seasons. Over winter, bulk density decreased significantly by 6.8 and 3.8% at 0–5 and 5–10 cm, respectively. A decrease ranging between 40.5 and 4.0% was observed for soil penetration resistance over winter, at 0–1.5 cm and 24.0–25.5 cm, respectively. The intensive and semi-intensive treatments produced significantly more available forage for grazers annually than the extensive treatment. Forage yields in late May to early June were negatively correlated with spring bulk density.


2011 ◽  
Vol 28 (4) ◽  
pp. 194-198 ◽  
Author(s):  
Oscar Bustos ◽  
Andrew Egan

Abstract A study of soil compaction associated with four harvesting systems—a forwarder working with a mechanized harvester and a rubber-tired cable skidder, a farm tractor, and a bulldozer, each of them coupled with a chainsaw felling—was conducted in a group selection harvest of a mixed hardwood stand in Maine. The bulldozer system was associated with the highest percentage differences in soil bulk density measured in machine tracks (16.9%), trail centerlines (15.7%), and harvested group selection units (13.1%) versus adjacent untrafficked areas, whereas the forwarder system was associated with the lowest percentage differences in soil bulk density measured in machine tracks (3.5%), trail centerlines (1.2%), and harvested group selection units (6.3%) versus adjacent untrafficked areas. Results will help to inform loggers and foresters on equipment selection, harvest planning, and the conservation of forest soils and soil productivity.


2002 ◽  
Vol 82 (2) ◽  
pp. 147-154 ◽  
Author(s):  
C. H. Li ◽  
B. L. Ma ◽  
T. Q. Zhang

Soil compaction associated with inappropriate maneuvering of field equipment, and/or modern cropping system negatively affect soil physical properties, and thus, may limit microbial activities and biochemical processes, which are important to nutrient bioavailability. An experiment was carried out using the pot-culture technique to determine the effect of bulk density on soil microbial populations and enzyme activities in an Eutric Cambisol sandy loam soil (United Nations’ classification) planted with maize (Zea mays L.) in the Experimental Farm of Henan Agricultural University, Henan, China (34°49′N, 113°40′E). Numbers of bacteria, fungi, and actinomycetes and the enzyme activities of invertase, polyphenol oxidase, catalase, urease, protease, and phosphatase were determined at various stages during the plant growing season. Microbial numbers were negatively and linearly related to soil bulk density. With increases in soil bulk density from 1.00 to 1.60 Mg m-3, total numbers of bacteria, fungi and actinomycetes declined by 26-39%. The strongest correlations between the soil microbial population and bulk density occurred at the plant growth stages of the 6 fully expanded leaf (V6) and anthesis (R1), with R2 > 0.90 (P< 0.01) for all three microorganism categories. Increasing soil bulk density was related quadratically to the activities of soil invertase and polyphenol oxidase, protease and catalase. It appears that the greatest activities of most soil enzymes occurred at a bulk density of 1.0 to 1.3 Mg m-3, which are optimum for most field crops. The plant growth stages also had an important impact on soil enzyme activities and microbial populations, with strong positive associations between soil microorganisms and enzyme activities with crop growth. Key words: Maize, soil enzymes, microbial population, soil compaction, bulk density, Zea mays


1988 ◽  
Vol 5 (2) ◽  
pp. 120-123 ◽  
Author(s):  
Stephen G. Shetron ◽  
John A. Sturos ◽  
Eunice Padley ◽  
Carl Trettin

Abstract The change in wheel track surface soil bulk densities was determined after a mechanized thinning in a northern red oak stand. Mean bulk density values of the 0 to 5 cm surface of the wheel tracks immediately after felling, bunching, and skidding were: 0.80 g/cc on the high use areas; 0.77 g/cc on the low use areas; and 0.42 g/cc in the undisturbed areas. No significant differences in surface soil bulk densities were found between several loading treatments using a four-wheel drive articulated forwarder. The data indicate that initial passes of the equipment produce most of the disturbance. No significant recovery in wheel track soil bulk densities occurred during the year following harvest regardless of treatment. North. J. Appl. For. 5:120-123, June 1988.


2012 ◽  
Vol 88 (03) ◽  
pp. 306-316 ◽  
Author(s):  
Richard Kabzems

Declines in forest productivity have been linked to losses of organic matter and soil porosity. To assess how removal of organic matter and soil compaction affect short-term ecosystem dynamics, pre-treatment and year 1, 5 and 10 post-treatment soil properties and post-treatment plant community responses were examined in a boreal trembling aspen (Populus tremuloidesMichx.)-dominated ecosystem in northeastern British Columbia. The experiment used a completely randomized design with three levels of organic matter removal (tree stems only; stems and slash; stems, slash and forest floor) and three levels of soil compaction (none, intermediate [2-cm impression], heavy [5-cm impression]). Removal of the forest floor initially stimulated aspen regeneration and significantly reduced height growth of aspen (198 cm compared to 472–480 cm) as well as white spruce (Picea glauca [Moench] Voss) height (82 cm compared to 154–156 cm). The compaction treatments had no effect on aspen regeneration density. At Year 10, heights of both aspen and white spruce were negatively correlated with upper mineral soil bulk density and were lowest on forest floor + whole tree removal treatments. Recovery of soil properties was occurring in the 0 cm to 2 cm layer of mineral soil. Bulk density values for the 0 cm to 10 cm depth remained above 86% of the maximum bulk density for the site, a soil condition where reduced tree growth can be expected.


1997 ◽  
Vol 75 (5) ◽  
pp. 723-729 ◽  
Author(s):  
Xiao-Lin Li ◽  
Jun-Ling Zhang ◽  
Eckhard George ◽  
Horst Marschner

The influence of an arbuscular mycorrhizal fungus, Glomus mosseae, on the adverse effects of soil compaction on growth and phosphorus (P) uptake of red clover was studied in a model experiment. The pots used in the experiment had three compartments, a central one with a soil bulk density of 1.3 g ∙ cm−3 and two outer compartments with three different levels of soil bulk density (1.3, 1.6, or 1.8 g ∙ cm−3). The soil in the outer compartments was fertilized with P and was either freely accessible to roots and hyphae, or separated by nets and accessible to hyphae only. At a soil bulk density of 1.3 g ∙ cm−3, mycorrhizal plants did not absorb more P than nonmycorrhizal plants except when access of roots to the outer compartments was restricted by nets. At high soil bulk density, root growth was drastically decreased. However, hyphae of G. mosseae absorbed P even from highly compacted soil, and induced a P-depletion zone of about 30 mm from the root surface. In consequence, at higher soil bulk density shoot P concentration and the total amount of P in the shoot were higher in mycorrhizal than in nonmycorrhizal plants. This experiment showed that hyphae of G. mosseae are more efficient in obtaining P from compacted soil than mycorrhizal or nonmycorrhizal roots of red clover. Key words: arbuscular mycorrhiza, phosphorus, red clover (Trifolium pratense L.), soil bulk density, soil compaction.


2005 ◽  
Vol 84 (1) ◽  
pp. 41-53 ◽  
Author(s):  
R.F. Dam ◽  
B.B. Mehdi ◽  
M.S.E. Burgess ◽  
C.A. Madramootoo ◽  
G.R. Mehuys ◽  
...  

1995 ◽  
Vol 75 (1) ◽  
pp. 149-152 ◽  
Author(s):  
M. R. Carter

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


Soil Research ◽  
2011 ◽  
Vol 49 (2) ◽  
pp. 135 ◽  
Author(s):  
M. A. Hamza ◽  
S. S. Al-Adawi ◽  
K. A. Al-Hinai

Reducing soil compaction is now an important issue in agriculture due to intensive use of farm machinery in different farm operations. This experiment was designed to study the influence of combinations of external load and soil water on soil compaction. Four soil water levels were combined with four external loads as follows: soil water—air-dry, 50% of field capacity, field capacity, and saturation; external load using different-sized tractors—no load (0 kg), small tractor (2638 kg), medium tractor (3912 kg), and large tractor (6964 kg). Soil bulk density, soil strength, and soil water infiltration rate were measured at 0–100, 100–200, and 200–300 mm soil depths. The 16 treatments were set up in a randomised block design with three replications. Combined increases in soil water and external load increased soil compaction, as indicated by increasing soil bulk density and soil strength and decreasing soil water infiltration rate. There was no significant interaction between soil water and external load for bulk density at all soil depths, but the interaction was significant for soil strength and infiltration rates at all soil depths. The ratio between the weight of the external load and the surface area of contact between the external load and the ground was important in determining the degree of surface soil compaction. Least compaction was produced by the medium tractor because it had the highest tyre/ground surface area contact. In general, the effects of soil water and external load on increasing soil bulk density and soil strength were greater in the topsoil than the subsoil.


1986 ◽  
Vol 66 (2) ◽  
pp. 197-207 ◽  
Author(s):  
M. R. CARTER ◽  
H. T. KUNELIUS

The soil physical, biological, and chemical condition was assessed under cultivated and direct-drilled systems for the annual establishment of Italian ryegrass (Lolium multiflorum Lam.) on Prince Edward Island. After 3 yr, the degree of tillage-induced soil compaction and change in soil biological and chemical properties were determined over the 0- to 24-cm soil depth, and compared with the soil structure under a permanent timothy (Phleum pratense L.) pasture. The study was conducted at two sites on a Charlottetown fine sandy loam, an Orthic Humo-Ferric Podzol (Haplorthod). Although the tillage comparisons produced significant changes in soil porosity, pore-size distribution, pore continuity, aggregation and soil strength, the range in physical properties was within the range considered optimum for soil structure. Soil strength was shown to exhibit marked temporal variation over the growing season. Changes in the distribution of soil microbial biomass C and N, percent organic C, pH and plant nutrients were evident between the establishment methods. Generally, soil chemical and biological conditions under direct-drilling were similar to those under permanent pasture. Comparison of the actual with the estimated maximum bulk density down the soil profile indicated that the propensity for soil consolidation or compaction was the same under the direct-drilling and cultivated systems and similar to that measured under permanent pasture. The annual establishment of Italian ryegrass, for 3 yr, by direct-drilling did not adversely affect soil structure or increase soil compaction. Key words: Direct-drilling, Italian ryegrass, soil structure, soil biological properties, tillage


Sign in / Sign up

Export Citation Format

Share Document