Artykuły w czasopismach na temat „Soil porosity”
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1
Kutílek, M., i L. Jendele. "The structural porosity in soil hydraulic functions – a review". Soil and Water Research 3, Special Issue No. 1 (30.06.2008): S7—S20. http://dx.doi.org/10.17221/1190-swr.
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Products of biological processes are the dominant factor of soil structure formation in A horizons, while in B horizons their role is less expressed. Soil structure influences dominantly the structural domain of the pore system in bimodal soils thus affecting soil hydraulic functions. The form of soil hydraulic functions depends upon the pore size distribution and generally upon configuration of the soil pore system. We used the functions derived for the lognormal pore size distribution and modified them to bi-modal soils. The derived equations were tested by experimental data of catalogued soils. The procedure leads to the separation of two mutually different domains of structural and matrix pores. The value of the pressure head (potential) separating the two domains is not constant and varies in a broad range. For each domain we obtained its water retention function and unsaturated hydraulic conductivity function. The separation of hydraulic functions for the two domains is a key problem in the solution of preferential flow and in controlling lateral flow between the structural and matrix domains. Water retention function is fully physically based while the conductivity function still keeps fitting parameters, too. Their simple relationship to tortuosity and pores connectivity was not confirmed. Since they differ substantially for matrix and structural domains, we suppose that there exists a great difference in configuration of porous systems in structural and matrix domains. The use of uniform fitting conductivity parameters for the whole range of pores is not justifiable.
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Garcia Moreno, R., T. Burykin, M. C. Diaz Alvarez i J. W. Crawford. "Effect of Management Practices on Soil Microstructure and Surface Microrelief". Applied and Environmental Soil Science 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/608275.
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Soil surface roughness (SSR) and porosity were evaluated from soils located in two farms belonging to the Plant Breeding Institute of the University of Sidney. The sites differ in their soil management practices; the first site (PBI) was strip-tilled during early fall (May 2010), and the second site (JBP) was under power harrowed tillage at the end of July 2010. Both sites were sampled in mid-August. At each location, SSR was measured for three 1 m2subplots using shadow analysis. To evaluate porosity and aggregation, soil samples were scanned using X-ray computed tomography with 5 μm resolution. The results show a strong negative correlation between SSR and porosity, 20.13% SSR and 41.38% porosity at PBI versus 42.00% SSR and 18.35% porosity at JBP. However, soil images show that when soil surface roughness is higher due to conservation and soil management practices, the processes of macroaggregation and structural porosity are enhanced. Further research must be conducted on SSR and porosity in different types of soils, as they provide complementary information on the evaluation of soil erosion susceptibility.
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Emerson, W. W., i D. McGarry. "Organic carbon and soil porosity". Soil Research 41, nr 1 (2003): 107. http://dx.doi.org/10.1071/sr01064.
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The %C within the top sandy 0.15 m of a sodic Hydrosol under native trees consisted of a constant %C in uncharged organic matter and a %C in negatively charged organic matter decreasing linearly with depth, as did the specific volume of the soil. The kaolinitic clay present was strongly bonded together. In an adjoining canefield cleared 10 years earlier, incorporation of burnt cane residues to 0.35 m had more than doubled the CEC of the soil, but had not generated structural porosity. The clay in the top 0.15 m remained strongly bonded together. The rate of increase in the specific volume of the sandy soil under trees with %C was twice that reported for surface aggregates of a silty soil from rotation plots on a Chromosol, and of sectioned clay cores from a Ferrosol under softwood scrub.The rate of increase in the specific volume of pores ≤30 μm diameter with %C was measured by the water retention of aggregates at 10 kPa suction, and was 50% more for the sandy soil than for the silty soil. The difference is ascribed to the dominance of mycorrhizal fungi under trees compared with bacteria under grass. Both agents are presumed to link particles together through acidic polysaccharide gel. Subsequent air-drying then leaves pores stable to wetting and drying. It is suggested that the increase in the plastic limit of silty soils is mainly due to pores stabilised in this way. Pores in decomposing plant residues coated with inorganics could also contribute.
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Tangyuan, N., H. Bin, J. Nianyuan, T. Shenzhong i L. Zengjia. "Effects of conservation tillage on soil porosity in maize-wheat cropping system". Plant, Soil and Environment 55, No. 8 (9.09.2009): 327–33. http://dx.doi.org/10.17221/25/2009-pse.
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A study was conducted on the effect of two single practices, including soil tillage and returning straw to soil, and their interaction on soil porosity of maize-wheat cropping system. Field experiments involved four tillage practices, including conventional tillage (C), zero-tillage (Z), harrow-tillage (H) and subsoil-tillage (S), with straw absent (A) or straw present (P). Total porosity, capillary porosity and non-capillary porosity of soil were investigated. The results showed that the soil total porosity of 0–10 soil layer was mostly affected; conventional tillage can increase the capillary porosity of soil, but the non-capillary porosity of S was the highest. Returning of straw can increase the porosity of soil. Through the analysis of affecting force, it can be concluded that interaction of soil tillage and straw is the most important factor to soil porosity, while the controlling factor to non-capillary porosity was soil tillage treatment.
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Startsev, A. D., i D. H. McNabb. "Effects of compaction on aeration and morphology of boreal forest soils in Alberta, Canada". Canadian Journal of Soil Science 89, nr 1 (1.02.2009): 45–56. http://dx.doi.org/10.4141/cjss06037.
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Poor soil aeration is a factor limiting the productivity of boreal forests in western Canada. Soil compaction reduces air-filled porosity, which is hypothesized to further restrict soil aeration. Soil morphology at nine clearcut sites in west-central Alberta that had been significantly compacted by ground-based harvesting equipment and soil in an adjacent non-trafficked control were related to air-filled porosity and redox regimes. A warm-season air-filled porosity of about 0.1 m3 m-3 separated soils having adequate or restricted aeration, and was confirmed by redox < 200 mV. The values applied to both the undisturbed and compacted soil. Ratios of Feo:Fed and acid-soluble Fe:Mn in concretions were only associated with hydromorphism of undisturbed soil. Compaction reduced soil aeration for 3–4 yr after harvesting, and changed morphology of moderately well-drained soil to imperfectly drained soil at two of four sites; faster removal of water because of slope or vegetation probably prevented changes at the other two sites. Morphology of better and poorer drained soils was not altered by compaction because they either remain adequately aerated or aeration was naturally restricted. Sites with moderately well-drained soils are most at risk of detrimental soil compaction and in need of protective measures to maintain their productivity in these forests. Key words: Soil morphology, drainage class, air-filled porosity, soil aeration, redox potential, boreal forest soils, compaction
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Kotorová, Dana, Jana Jakubová i Ladislav Kováč. "Dependence of Heavy Soil Transport Function on Soil Profile Depth". Agriculture (Polnohospodárstvo) 57, nr 2 (1.06.2011): 45–52. http://dx.doi.org/10.2478/v10207-011-0005-0.
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Dependence of Heavy Soil Transport Function on Soil Profile DepthThe aim of this work was to quantify the effect of soil profile depth on the transport function of heavy soils. Treatments were carried out between 2006 and 2009 in Milhostov. Two variants were examined : the (conventional soil tillage and long-time no-tilled variant). Soil samples were taken in spring and autumn from soil profile depth of 0.00-0.60 m from each 0.10 m. For further evaluation the average values were used. Particle size composition, bulk density, total porosity and maximum capillary capacity were determined. Content of clay particles in soil profile was in interval 59.64-68.53% and such soils are characterised in the range from clay-loamy soil to clayey soil. The bulk density increased with the depth of soil profile and its values reached 1 184-1 646 kg m-3. The total porosity was in range 37.68-55.17% and it decreased with the depth of soil profile. The values of maximum capillary capacity were characterised for heavy soils with high content of clay particles. The depth had statistically significant effect on all observed parameters. In average, on both variants the bulk density was higher than 1 400 kg m-3, the total porosity was lower than 47% and the content of clay was higher than 30%, pointing to the possibility of soil compaction, which will result in reduced transport function of heavy soils.
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Hussein Razzaq Nayyef. "Effect of continuous cultivation and soil texture on some soil properties". GSC Advanced Research and Reviews 13, nr 1 (30.10.2022): 077–84. http://dx.doi.org/10.30574/gscarr.2022.13.1.0271.
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The effects of soil continuous cultivation and soil texture on some of its properties, electrical conductivity, total porosity, and calcium carbonate content and soil penetration resistance. Six samples of soil material for a layer of 0-30 cm were collected from three different texture sites are Clay, Loam and Loamy Sand in Basra Governorate for three sites Abi al-Khasib, Karma and Zubair. Three of these samples represented the treatment of soil continuous cultivation, soil planted with alfalfa crop (Medicago sativa) for 7 consecutive years, and the other three samples from the same sites for uncultivated soil with three replications for each sample. The results showed a decrease in the values of electrical conductivity, calcium carbonate, soil penetration resistance, and an increase in soil porosity values in cultivated soils. The lowest EC values were 4.1, 5.3 and 6.2 dS. m-1 for soils with textures Loamy sand, Loam and Clay, respectively, and for CaCO3 of 182.3 g. kg-1 in Loamy sand, 266.7 g. kg-1 and 310 g. kg-1 for Loam and Clay soils, respectively, and for resistance to penetration of 550 KN.m-1 for clay soils. While it was 620 KN.m-1, and 714 KN.m-1, for loam soil and loamy sand soil, respectively, compared to uncultivated soil. While the soil porosity values increased for cultivated soils compared with uncultivated soils and the values of 43%, 48.53% and 53.4%, for soils with textures Loamy sand, Loam and Clay respectively, And for the average weighted diameter of 0.2537 mm, 0.2817 mm, 0.3640 mm, for soils with textures Loamy sand, Loam and Clay, respectively.
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Juliev, M., B. Matyakubov, O. Khakberdiev, X. Abdurasulov, L. Gafurova, O. Ergasheva, U. Panjiev i B. Chorikulov. "Influence of erosion on the mechanical composition and physical properties of serozems on rainfed soils, Tashkent province, Uzbekistan". IOP Conference Series: Earth and Environmental Science 1068, nr 1 (1.07.2022): 012005. http://dx.doi.org/10.1088/1755-1315/1068/1/012005.
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Abstract The problem of soil protection from erosion is relevant for many countries in the arid zone of the world, including the territory of Uzbekistan. In the republic, the main arrays of crops are located on rainfed lands, where the crop is created only due to moisture in precipitation. The amount of porosity (duty cycle) of soils is determined mainly by specific and bulk mass, mechanical composition, and humus content. Porosity of soils decreases from unwashed soils to washed away and down the profile. In the arable horizons of unwashed rainfed soils, it is 52%, washed out - 47.49%. Deeper in the profile, in horizons transitional to soil, due to a sharp increase in density and a decrease in the humus content in all soils, regardless of erosion, Porosity sharply drops to 48-50%. Thus, with a small bulk mass, the overall porosity of rainfed typical serozems is generally satisfactory, since it provides good soil aeration and the use of precipitation, only on highly washed away soils the porosity decreases markedly and the absorption of precipitation is slightly worsened.
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Foti, S., i R. Lancellotta. "Soil porosity from seismic velocities". Géotechnique 54, nr 8 (październik 2004): 551–54. http://dx.doi.org/10.1680/geot.2004.54.8.551.
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Foti, S., i R. Lancellotta. "Soil porosity from seismic velocities". Géotechnique 54, nr 8 (sierpień 2004): 551–54. http://dx.doi.org/10.1680/geot.54.8.551.52010.
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Tavares Filho, João, i Daniel Tessier. "Effects of different management systems on porosity of oxisols in Paraná, Brazil". Revista Brasileira de Ciência do Solo 34, nr 3 (czerwiec 2010): 899–906. http://dx.doi.org/10.1590/s0100-06832010000300031.
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Soils play a fundamental role in the production of human foods. The Oxisols in the state of Paraná are among the richest and most productive soils in Brazil, but degradation and low porosity are frequently documented, due to intensive farming involving various management strategies and the application of high-tech solutions. This study aims to investigate changes in the porosity of two Red Oxisols (Latossolos Vermelhos), denoted LVef (eutroferric) and LVdf (dystroferric) under conventional and no-tillage soil management, with a succession of annual crops of soybean, maize and wheat over a continuous period of more than 20 years. After describing the soil profiles under native forest, no-tillage management and conventional tillage using the crop profile method, deformed and non-deformed soil samples were collected from the volumes most compacted by human intervention and the physical, chemical and mineralogical properties analyzed. The various porosity classes (total pore volume, inter-aggregate porosity between channels and biological cavities) and intra-aggregate porosity (determined in 10 cm³ saturated clods subjected to a pressure of -10 kPa to obtain a pore volume with a radius (r eq), > 15 μm and < 15 μm). The results showed that the effects of no-tillage farming on porosity are more pronounced in both soil types. Porosity of the LVdf was higher than pf the LVef soil, whatever the management type. In the LVdf soil, only pores with a radius of > 15 μm were affected by farming whereas in the LVef soil, pores with a radius of < 15 μm were affected as well.
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Liu, Chang, Fuguo Tong, Long Yan, Hongbo Zhou i Shuang Hao. "Effect of Porosity on Soil-Water Retention Curves: Theoretical and Experimental Aspects". Geofluids 2020 (22.12.2020): 1–8. http://dx.doi.org/10.1155/2020/6671479.
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Porosity change is a common characteristic of natural soils in fluid-solid interaction problems, which can lead to an obvious change of the soil-water retention curve (SWRC). The influence of porosity on soil water retention phenomena is investigated by a theoretical model and an experimental test in this study. A model expressing the change in suction with porosity and effective saturation is put forward theoretically. The model is based on an idealization of three-phase porous materials, the pore structures of which are homogeneous and isotropic. It accounts for the porosity effect on soil water retention, using four parameters with clear physical meanings. The presented model can obtain the SWRC at any porosity, which will reduce the test number required in characterizing the hydraulic behavior of soil. A laboratory experiment for loamy sand with different porosities is performed. The test results show that suction has a significant variation with changes in porosity and decreases with the increase of porosity. The formulation is verified by both the test data and the literature data for FEBEX bentonite and Boom clay. The very good agreements between measured and predicted results show that the SWRC model is reliable and feasible for various soils.
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Cucci, Giovanna, Giovanni Lacolla, Marcello Pagliai i Nadia Vignozzi. "Effect of reclamation on the structure of silty-clay soils irrigated with saline-sodic waters". International Agrophysics 29, nr 1 (1.01.2015): 23–30. http://dx.doi.org/10.1515/intag-2015-0005.
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Abstract The objective of the work was to evaluate, by using the micromorphometric method, the effects of reclamation on porosity of two different clay loam soils irrigated with saline-sodic waters. Soil samples of the Ap horizon were put in cylindrical containers and irrigated with 9 types of saline-sodic waters (3 levels of salinity combined with 3 levels of sodicity). After a 4-year period, correction treatments were initiated by addition of calcium sulphate and leaching until electrical conductivity and sodium absorption ratio values of the drainage water matched 3 dS m-1 and 9, respectively. After 2 years of correction treatments, undisturbed soil samples were taken from the surface layer and soil thin sections for porosity measurements. Both soils did not show critical macroporosity values (> 10%, below this threshold a soil is classified as compact). Nevertheless, the soils exhibited a different behaviour: total porosity of the Pachic Haploxeroll soil was not affected by difference in water salinity and alkalinity; on the contrary, the Udertic Ustochrept soil showed a lower porosity associated with higher salt concentration in the irrigation waters. This may be due to the different iron and aluminium sesquioxides content and, as a consequence, a different effect on soil aggregate stability.
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HARALDSEN, T. K. "Effects of cattle slurry and cultivation on air exchange in sandy and silty soils from northern Norway". Agricultural and Food Science 8, nr 1 (1.01.1999): 29–44. http://dx.doi.org/10.23986/afsci.5623.
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Gas diffusivity and permeability, and air-filled porosity, were measured in undisturbed soil cores at four water potentials between -1.5 kPa and -60 kPa. Virgin (never ploughed) and cultivated sandy and silty soils from two sites in northern Norway were used in the investigation. The cultivated soils had lower air-filled porosity and gas diffusivity than the virgin ones. Application of slurry (50 Mg ha-1) decreased gas diffusivity and changed the relationship between relative diffusivity and air-filled porosity for both the virgin and cultivated sandy soils and the virgin silty soil. The gas permeability of both the virgin and cultivated silty soil was low, and the relative diffusivity at field capacity less than the limit below which plant growth is affected. ;
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Dung, Tran Van, Ngo Phuong Ngoc, Le Van Dang i Ngo Ngoc Hung. "Impact of cover crop and mulching on soil physical properties and soil nutrients in a citrus orchard". PeerJ 10 (5.10.2022): e14170. http://dx.doi.org/10.7717/peerj.14170.
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Background Cover crops and mulching can ameliorate soil porosity and nutrient availability, but their effects on the physical characteristics and nutrients in the raised bed soils are unclear. Methods The field experiment was conducted in a pomelo orchard from 2019 to 2021, with an area of 1,500 m2. The treatments included control (no cover crop), non-legume cover crop (Commelina communis L.), legume cover crop (Arachis pintoi Krabov & W.C. Gregory), and rice straw mulching (Oryza sativa L.). At the end of each year (2019, 2020, and 2021), soil samples were collected at four different layers (0–10, 10–20, 20–30, and 30–40 cm) in each treatment. Soil bulk density, soil porosity, and the concentration of nutrients in the soil were investigated. Results The results revealed that soil bulk density at two depths, 0–10 and 10–20 cm, was reduced by 0.07 and 0.08 g cm−3 by rice straw mulch and a leguminous cover crop, thus, increasing soil porosity by ~2.74% and ~3.01%, respectively. Soil nutrients (Ca, K, Fe, and Zn) at topsoil (0–10 cm) and subsoil (10–20 cm) layers were not significantly different in the first year, but those nutrients (Ca, K, Fe, and Zn) improved greatly in the second and third years. Conclusions Legume cover crops and straw mulch enhanced soil porosity and plant nutrient availability (Ca, K, Fe, and Zn). These conservation practices best benefit fruit orchards cultivated in the raised bed soils.
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Yazdanpanah, N. "CO<sub>2</sub> emission and structural characteristics of two calcareous soils amended with municipal solid waste and plant residue". Solid Earth Discussions 7, nr 4 (9.11.2015): 3151–77. http://dx.doi.org/10.5194/sed-7-3151-2015.
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Abstract. This investigation examines the effect of different amendments on selected soil physical and biological properties over a twenty four month period in two cropland fields. Urban municipal solid waste (MSW) compost and alfalfa residue (AR) were used as different organic amendments at the rates of 0 (control), 10 and 30 Mg ha−1 to a clay loam soil and a loamy sand soil in a semiarid region. Result showed that the soil improvement was controlled by the application rate and decomposability of amendments and soil type. The addition of organic amendments to the soils improved aggregate stability and consequently enhanced total porosity, especially macro pores fraction. The increased soil organic carbon (SOC) and total porosity values as compared to the control treatment were greater in the loamy sand soil than in the clay loam soil. Moreover, compared to the microbial respiration of control plots, the application of MSW resulted in higher values of microbial respiration in the clay loam soil than in the loamy sand soil, whereas the reverse order was found for AR. Linear and power functions were provided for the relationships between microbial respiration and SOC in the loamy sand and clay loam soils, respectively. Also, CO2 emission was stimulated significantly as power functions of the total porosity and the ratio of macro to micro pores. However, the soil microbial respiration and carbon storage improved aggregate stability and pore size distribution, as a response, soil porosity especially macro pores fraction controlled CO2 flux.
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Yazdanpanah, N. "CO<sub>2</sub> emission and structural characteristics of two calcareous soils amended with municipal solid waste and plant residue". Solid Earth 7, nr 1 (26.01.2016): 105–14. http://dx.doi.org/10.5194/se-7-105-2016.
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Abstract. This investigation examines the effect of different amendments on selected soil physical and biological properties over a 24-month period in two cropland fields. Urban municipal solid waste (MSW) compost and alfalfa residue (AR) were used as different organic amendments at the rates of 0 (control), 10 and 30 Mg ha−1 to a clay loam soil and a loamy sand soil in a semiarid region. Results showed that the soil improvement was controlled by the application rate and decomposability of amendments and soil type. The addition of organic amendments to the soils improved aggregate stability and consequently enhanced total porosity, especially macropore fraction. The increased soil organic carbon (SOC) and total porosity values as compared to the control treatment were greater in the loamy sand soil than in the clay loam soil. Moreover, compared to the microbial respiration of control plots, the application of MSW resulted in higher values of microbial respiration in the clay loam soil than in the loamy sand soil, whereas the reverse was found for AR. Linear and power functions were provided for the relationships between microbial respiration and SOC in the loamy sand and clay loam soils, respectively. Also, CO2 emission was stimulated significantly as power functions of the total porosity and the ratio of macroporosity to microporosity. However, the soil microbial respiration and carbon storage improved aggregate stability and pore size distribution, and as a response, soil porosity, especially the macropore fraction, controlled CO2 flux.
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Abukari, Ammal, Donkor Christian i Kwame Ochire-Boadu. "Bulk density and porosity of soils influenced by skidding operations in the Nkrankwanta Off-Forest Reserve of Ghana". Advances in Forestry Science 8, nr 2 (1.09.2021): 1409–15. http://dx.doi.org/10.34062/afs.v8i2.9530.
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Heavy forest machinery used in skidding has the capacity to influence the physical properties of soils. These may possibly lead to an upsurge in soil disruption and compaction of the soil surface decreases forest soil fertilities. This study assesses the effects of skidding on some soil physical properties such as the soil bulk density and porosity in the Nkrankwanta off-forest reserve in Ghana. The treatments comprised of four traffic intensity levels (1, 5, 10, and 15 passes) of the Mercedes Benz skidder (MB) Trac 1800 and a slope of two levels (less than 20 % and greater than 20 %) in a completely randomized block design. In addition, porosity and soil bulk density were assessed at varied distances from the MB Trac 1800. Soil bulk density results showed increasing trends with traffic frequency. Soil bulk density measured in the undisturbed area was 0.64 g cm-3 and 0.56 g cm-3 at slopes of less than 20% and greater than 20%, respectively. On the skid trail, soil bulk density significantly increased with traffic frequency (p<0.05). However soil porosity declined. Soil porosity estimated in uninterrupted area was 59.10 % and 57.40 % at < 20% and > 20% slope, respectively. Soil porosity was significantly influenced via different skidder passes (p<0.05). The soil physical properties were not influenced by the steepness of the slope however acted together in the number of passes to influence soil porosity. The impacts of the skidder on soil physical properties were significantly apparent at distances of 2 m to each sideway of the skidding trail. In conclusion, distinct responsiveness ought to be considered throughout the operations of skidding to curtail unfriendly influences on soil physical properties in ground-base skidding.
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Santos, Carlos Renato dos, Antônio Celso Dantas Antonino, Richard John Heck, Leandro Ricardo Rodrigues de Lucena, Alex Cristóvão Holanda de Oliveira, Antonio Samuel Alves da Silva, Borko Stosic i Romulo Simões Cezar Menezes. "3D soil void space lacunarity as an index of degradation after land use change". Acta Scientiarum. Agronomy 42 (3.04.2020): e42491. http://dx.doi.org/10.4025/actasciagron.v42i1.42491.
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In this work, lacunarity analysis is performed on soil pores segmented by the pure voxel extraction method from soil tomography images. The conversion of forest to sugarcane plantation was found to result in higher sugarcane soil pore lacunarity than that of native forest soil, while the porosity was found to be lower. More precisely, this study shows that native forest has more porous soil with a more uniform spatial distribution of pores, while sugarcane soil has lower porosity and a more heterogeneous pore distribution. Moreover, validation through multivariate statistics demonstrates that lacunarity can be considered a relevant index of clustering and can explain the variability among soils under different land use systems. While porosity by itself represents a fundamental concept for quantification of the impact of land use change, the current findings demonstrate that the spatial distribution of pores also plays an important role and that pore lacunarity can be adopted as a complementary tool in studies directed at quantifying the effect of human intervention on soils.
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Camarinha, Pedro I. M., Silvio J. C. Simões, George P. Bernardes i Isabel C. B. Trannin. "Correlating Soil Porosity and Respective Geological Unit in Paraíba do Sul Valley, Brazil - A Geostatistical Methodology Proposal". Soils and Rocks 35, nr 3 (1.09.2012): 209–22. http://dx.doi.org/10.28927/sr.353209.
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This manuscript aims proposing a methodology for correlating soil porosity to the respective geological units using geostatistical analysis techniques, including interpolation data by kriging. The site studied was in Lorena municipality, Paraíba do Sul Valley, southeastern Brazil. Specifically all studies were carried out within an area of 12 km2 located at Santa Edwirges farm. The database comprehended 41 soil samples taken at different geological and geomorphologic units at three different depths: surface, 50 cm and 100 cm depth. The geostatistical analyses results were correlated to a geological mapping specifically elaborated for the site. This mapping accounts for two different geological formations and a geological contact characterized by a shearing zone. The results indicate the existence of a significant relationship between the soil porosity and the respective geological units. The studies revealed that the residual soils from weathered granitic rocks tend to have higher porosities than the residual soils from weathered biotite gneiss rocks, while the soil porosity within the shearing zone is relatively un-sensitive to the respective geological formation. The spatial patterns observed were efficient to evaluate the relationship between the soil porosity, geology unit and the and geomorphology showing a good potential for correlating with others soil properties such as hydraulic conductivity, soil water retention curves and erosion potentials.
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Vopravil, Jan, Pavel Formánek i Tomáš Khel. "Comparison of the physical properties of soils belonging to different reference soil groups". Soil and Water Research 16, No. 1 (11.12.2020): 29–38. http://dx.doi.org/10.17221/31/2020-swr.
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Soil properties can be influenced by long-term agricultural management practices as described in pedological literature. In this study, selected physical properties (particle density and bulk density, total porosity, maximum capillary water capacity, minimum air capacity, field capacity, permanent wilting point and available water capacity) of topsoils from different reference soil groups (Cambisols, Luvisols, Fluvisols, Chernozems and Phaeozems, Leptosols, Stagnosols and Gleysols) were sampled and analysed in the years 2016–2017. The topsoil samples were taken from points of so-called S (specific) soil pits to be sampled from the General Soil Survey of Agricultural Soils (GSSAS) which was accomplished in the years 1961–1970. In addition, some of the properties were also compared with those measured during the GSSAS. Recognising the properties, only the particle density, the maximum capillary water capacity, the permanent wilting point and the available water capacity of the topsoil of the individual soil groups were statistically significantly (P < 0.05) different. A comparison of the physical properties with those analysed after more than 40 years was performed, the bulk density increased and the total porosity decreased in the topsoil of the major part of the studied soil groups.
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Nguyen, Binh Thanh, Hai Thien Hoa, Van Thi Hong Ngo, Tra Thanh Duong i Brian R. Wilson. "Comparative study of soil properties under various cultivation regimes of different crops". Soil Research 49, nr 7 (2011): 595. http://dx.doi.org/10.1071/sr11126.
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Establishment of cover crops is an effective way to reverse the soil fertility decline, which can be caused by a range of inappropriate traditional agriculture practices, particularly tillage and inorganic fertiliser application. In this study, soil properties were assessed under various cultivation regimes of different crops, including legumes, grass, and nursery natural rubber (NR) trees (Hevea brasiliensis Muell. Arg.), in southern Vietnam. The crops studied had all been growing for 7 years commencing in 1999, on light-textured Acrisols. Soils under the cultivation regime of creeping legumes including Calopogonium caeruleum, Pueraria phaseoloides, and Stylosanthes gracilis had significantly higher carbon (C) and nitrogen (N) concentrations and porosity than soils under the other management types studied. Soils under Brachiaria ruziziensis and P. phaseoloides had the highest aggregate stability. Cultivation regimes with tillage, field traffic, and inorganic fertilisers applied to nursery NR trees increased phosphorus (P) availability, but this was accompanied by increased soil compaction and reductions in most of the other soil properties analysed. Relative to the nursery NR cultivation, creeping-legume cultivation increased soil C concentration (by 95%), soil pHH2O (by 19%), macro-aggregates (by 29%), and porosity (by 8%). From principal component analysis, three soil properties—soil organic carbon (SOC), porosity, and P availability—were selected as key indicators suitable for the evaluation of the effects of cultivation on soils. Establishment of C. caeruleum and B. ruziziensis was most effective in improving soil C content, and soil porosity was significantly higher under C. caeruleum and P. phaseoloides. These findings suggest that each cover crop had its own dominant agro-characteristics and that selection of a cover crop to either improve soil fertility or reduce compaction should be considered by farmers in this region.
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Pagliai, Marcello, i Maria De Nobili. "Relationships between soil porosity, root development and soil enzyme activity in cultivated soils". Geoderma 56, nr 1-4 (marzec 1993): 243–56. http://dx.doi.org/10.1016/0016-7061(93)90114-z.
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Emerson, WW. "Structural decline of soils, assessment and prevention". Soil Research 29, nr 6 (1991): 905. http://dx.doi.org/10.1071/sr9910905.
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Two extreme textural types of cultivated surface soils are mainly considered here, non-shrinking red-brown earths and highly shrinking cracking clays. Total porosity is used to assess the structural status of the former. Values are compared with the highest and lowest values found in the field. For the latter, the criterion used is the porosity of dry aggregates or clods. Values here are taken from the literature. To find out why inter-particle bonding in soil aggregates is insufficient to stop structural decline, a scheme has been developed which includes a modified version of Emerson's (1967) classification of soil aggregates. Slaking is carefully assessed. The bulk density of a cube made from soil at 'field capacity' is measured as well as testing another for dispersion. Class 3 is now divided into 3a and 3b, according to the degree of dispersion of remoulded soil in water. Also apart from soils which disperse spontaneously from dry, classes 1 and 2, the dispersion of all soils is assessed after remoulding at 'field capacity'. It has been found that the red-brown earth site which had the best visual structure also had the largest total porosity and aggregates in class 4. At the worst site, aggregates were in class 3a and the porosity had been reduced to that of the soil cube. For cracking clays, porosity is appreciably higher where the aggregates are in class 4 rather than class 3a. Water content/dispersion curves are presented for the clays showing the extent of the increase in OD apparently associated with the presence of carbonate. Dispersion of sheared, class 3a soil immersed in water is only an outward sign of the structural damage caused when the soil is sheared too wet. If the soil is dried instead, porosity is still lost. Mechanisms are suggested by which the structure of class 3a clay soils are improved by adding carbonate. The slumping of red-brown earths and the use of surface dressings of gypsum to prevent severe dispersion after cultivation wet are discussed. The structural stability of aggregates in the other five classes is briefly considered. Classes 1 and 2 require an ameliorant to be added, the rest pose few problems.
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Rolf, Kaj. "Soil Physical Effects of Pneumatic Subsoil Loosening Using Aterralift Soil Aerator". Arboriculture & Urban Forestry 18, nr 5 (1.09.1992): 235–40. http://dx.doi.org/10.48044/jauf.1992.046.
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The effects of pneumatic subsoiling using a Terralift soil aerator on a number of soil physical parameters were measured at sites with sandy loam and loam over clay loam, respectively. The subsoil was compacted under controlled conditions prior to aeration. In the sandy loam, aeration led to a decreased bulkdensity, an increase in porosity (mainly as an increase in macro-porosity) and an increase in saturated hydraulic conductivity and air permeability. Penetration resistance was lowered at this site. After aeration at the loam soil site, measurements indicated that bulk density increased, porosity decreased, there were no changes in saturated hydraulic conductivity and only a small increase in air permeability.
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Rashid, M. F. A., N. Alias, K. Ahmad, R. Sa’ari, M. Z. Ramli, M. I. Shahrin i Z. Ibrahim. "Hydrocarbon Penetration in Multi-Porosity Soil". IOP Conference Series: Earth and Environmental Science 494 (26.08.2020): 012007. http://dx.doi.org/10.1088/1755-1315/494/1/012007.
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Klovanych, Sergii, i Leszek Malyszko. "Soil plasticity with a different porosity". MATEC Web of Conferences 117 (2017): 00114. http://dx.doi.org/10.1051/matecconf/201711700114.
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D'Acqui, Luigi Paolo, Giacomo Certini, Martina Cambi i Enrico Marchi. "Machinery’s impact on forest soil porosity". Journal of Terramechanics 91 (październik 2020): 65–71. http://dx.doi.org/10.1016/j.jterra.2020.05.002.
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Dyba, V. P., i E. G. Skibin. "Change in Soil Porosity under Load". IOP Conference Series: Materials Science and Engineering 262 (listopad 2017): 012225. http://dx.doi.org/10.1088/1757-899x/262/1/012225.
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Yu, Bingqin, Changkun Xie, Shize Cai, Yan Chen, Yongpeng Lv, Zulan Mo, Tianlei Liu i Zhiwen Yang. "Effects of Tree Root Density on Soil Total Porosity and Non-Capillary Porosity Using a Ground-Penetrating Tree Radar Unit in Shanghai, China". Sustainability 10, nr 12 (6.12.2018): 4640. http://dx.doi.org/10.3390/su10124640.
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To explore the relationship between arbor root density and corresponding physical soil properties (total porosity, non-capillary porosity, specific weight, bulk density, moisture content, and permeability), noninvasive methods such as Tree Radar Unit (TRU) were utilized to detect the root systems of 10 species of tree that are commonly used in Shanghai green spaces with more than 70% frequency of occurrence. Using TRU and soil investigation, root density and soil porous features were determined for different tree species, depth slices, and distances. The relationships among root density, soil porosity, and non-capillary porosity were identified using variance analysis and regression analysis. The results indicated that root density decreased with increasing distance from the trunk and soil depth. Soil porosity and non-capillary porosity had significantly positive and linear correlations with root density. Compared with lawns, trees such as Zelkova serrata, Koelreuteria paniculata, Cinnamomum camphora, and Metasequoia glyptostroboides had the greatest effects on soil improvement through soil porosity and non-capillary porosity. Due to the spatial distribution of root systems, trees could be divided into three types based on their influence at various soil depths.
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Satyanaga, Alfrendo, Nail Bairakhmetov, Jong R. Kim i Sung-Woo Moon. "Role of Bimodal Water Retention Curve on the Unsaturated Shear Strength". Applied Sciences 12, nr 3 (25.01.2022): 1266. http://dx.doi.org/10.3390/app12031266.
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Changes in climatic conditions are expected globally resulting in a higher rainfall intensity and longer duration of rainfall. The increase in the rainwater infiltration into the soil contributes to many geotechnical issues, such as excessive settlement, retaining wall failure and rainfall-induced slope failures. These geotechnical problems could be mitigated by the improvement of the problematic soil with the incorporation of the unsaturated soil mechanic principles. Dual-porosity soils or soils with bimodal water retention curve (WRC) are able to retain more water during prolonged drying and they would be able to drain out water faster during intense rainfall to maintain the slope stability. The objective of this study is to investigate the characteristics of the unsaturated shear strength of soil with bimodal WRC. In addition, the new mathematical equation is proposed to estimate the unsaturated shear strength of soils with a bimodal WRC. The results of the study indicated that the nonlinearity of the unsaturated shear strength is a function of the shape of bimodal WRC limited by the first and second air-entry value (AEV) of dual-porosity soils. The proposed equation agreed well with the experimental data of the unsaturated shear strength for dual-porosity soil.
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Adamczuk, Agnieszka, i Grzegorz Jozefaciuk. "Impact of Chitosan on the Mechanical Stability of Soils". Molecules 27, nr 7 (31.03.2022): 2273. http://dx.doi.org/10.3390/molecules27072273.
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Chitosan is becoming increasingly applied in agriculture, mostly as a powder, however little is known about its effect on soil mechanical properties. Uniaxial compression test was performed for cylindrical soil aggregates prepared from four soils of various properties (very acidic Podzol, acidic Arenosol, neutral Fluvisol and alkaline Umbrisol) containing different proportions of two kinds of chitosan (CS1 of higher molecular mass and lower deacetylation degree, and CS2 of lower molecular mass and higher deacetylation degree), pretreated with 1 and 10 wetting–drying cycles. In most cases increasing chitosan rates successively decreased the mechanical stability of soils that was accompanied by a tendential increase in soil porosity. In one case (Fluvisol treated with CS2) the porosity decreased and mechanical stability increased with increasing chitosan dose. The behavior of acidic soils (Podzol and Arenosol) treated with CS2, differed from the other soils: after an initial decrease, the strength of aggregates increased with increasing chitosan amendment, despite the porosity consequently decreasing. After 10 wetting–drying cycles, the strength of the aggregates of acidic soils appeared to increase while it decreased for neutral and alkaline soils. Possible mechanisms of soil–chitosan interactions affecting mechanical strength are discussed and linked with soil water stability and wettability.
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Makhmutov, M. M., A. I. Chepurnoy, M. M. Makhmutov i A. K. Dzhabarov. "Influence of absolute soil humidity on the porosity of soil packing". Traktory i sel hozmashiny 79, nr 3 (15.03.2012): 35–36. http://dx.doi.org/10.17816/0321-4443-69384.
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The influence of absolute soil humidity on the porosity of soil packing is shown. It is noted that soil porosity will be reduced at the expense of decreasing of air pores and increasing of solid particles volume as a result of soil compression with mover, strake, block etc. at constant humidity. The analysis of obtained models is given.
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Syarifudin, Achmad, i Alfrendo Satyanaga. "Variability of Bimodal Soil-Water Characteristic Curves under Different Confining Pressures". Applied and Environmental Soil Science 2021 (5.06.2021): 1–10. http://dx.doi.org/10.1155/2021/5569491.
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Soils with two subcurves of Soil-Water Characteristic Curve (SWCC) (dual porosity soils) might be found within various residual soils. Soils located in different depths have different confining pressure. Residual soils are found in the unsaturated zones due to the deep groundwater table. There is a linear correlation between the hydraulic properties of the soil in the unsaturated area and that of its unsaturated properties. This study aims to examine the influence of the confining pressure towards the SWCC of dual porosity soil. The scope of this study involves measurements of the drying and wetting SWCC using Tempe cells, pressure plates, and an advanced triaxial apparatus. In this study, the mathematical equations were developed to explain the effect of confining pressure on SWCC. The experimental results indicated that the dual porosity soil exhibits bimodal characteristics for the drying curve of SWCC and it exhibits unimodal characteristics for the wetting curve of SWCC. As the confining pressure increases, the air entry values, the inflection points, and the standard deviation of drying SWCC increase. In addition, the hysteresis of SWCC is becoming smaller with the increasing confining pressure.
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STONE, J. A., i K. C. WIRES. "WATER CONTENT AND SOIL CORE VOLUME ON BROOKSTON CLAY LOAM". Canadian Journal of Soil Science 70, nr 2 (1.05.1990): 255–58. http://dx.doi.org/10.4141/cjss90-026.
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Soil core volumes, from a long-term fertility experiment on Brookston clay loam, were adjusted for soil water content at sampling to explain large year-to-year fluctuations in bulk density and porosity. Adjusting the long-term soil core data decreased values of bulk density, total porosity, and air-filled porosity and reduced the variation between years. However, the year-to-year variation remained highly significant. Year-to-year fluctuations in bulk density and porosity on Brookston clay loam soil do not appear to be solely the result of changes in soil volume due to differences in soil water content at the time of sampling. Key words: Shrinkage, bulk density, porosity
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GREVERS, M. C. J., i A. A. BOMKE. "TILLAGE PRACTICES ON A NORTHERN CLAY SOIL: EFFECTS OF SOD BREAKING METHODS ON CROP PRODUCTION AND SOIL PHYSICAL PROPERTIES". Canadian Journal of Soil Science 66, nr 3 (1.08.1986): 385–95. http://dx.doi.org/10.4141/cjss86-041.
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Crop production in northern regions is mainly affected by a short growing season, and can also be further limited on heavy-textured soils by cool, wet spring conditions. Selected sod breaking practices were carried out resulting in maximum differences with respect to sod burial and soil physical properties. Soil physical properties measured included bulk density, air-filled porosity, aggregate size distribution, surface roughness and soil temperature. The main effects of the different tillage systems were: (1) differences in soil structure in terms of density and air-filled porosity, and (2) differences in the degree of residue incorporation. Moldboard plowing resulted in more favorable aeration porosity and soil temperature in spring than chisel plowing or discing. Rotovating prior to either moldboard plowing or chisel plowing had only a minor effect on soil physical conditions. In general the more effective the tillage was in incorporating crop residue and thatch, the higher was the subsequent soil temperature during the first 5 wk of the growing season. The differences in crop production followed the same trend as did differences in soil structure. This effect persisted through the third cropping season. Increasing levels of fertilizer N increased barley yields in all tillage treatments but did not offset the effect of physical differences caused by the tillage implements. Key words: Northern soils, tillage, soil temperature, soil structure, fertilizer nitrogen, barley
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Mtyobile, Mxolisi, Lindah Muzangwa i Pearson Nyari Stephano Mnkeni. "Tillage and crop rotation effects on soil carbon and selected soil physical properties in a Haplic Cambisol in Eastern Cape, South Africa". Soil and Water Research 15, No. 1 (9.12.2019): 47–54. http://dx.doi.org/10.17221/176/2018-swr.
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The effects of tillage and crop rotation on the soil carbon, the soil bulk density, the porosity and the soil water content were evaluated during the 6<sup>th</sup> season of an on-going field trial at the University of Fort Hare Farm (UFH), South Africa. Two tillage systems; conventional tillage (CT) and no-till and crop rotations; maize (Zea mays L.)-fallow-maize (MFM), maize-fallow-soybean (Glycine max L.) (MFS); maize-wheat (Triticum aestivum L.)-maize (MWM) and maize-wheat-soybean (MWS) were evaluated. The field experiment was a 2 × 4 factorial, laid out in a randomised complete design. The crop residues were retained for the no-till plots and incorporated for the CT plots, after each cropping season. No significant effects (P > 0.05) of the tillage and crop rotation on the bulk density were observed. However, the values ranged from 1.32 to1.37 g/cm<sup>3</sup>. Significant interaction effects of the tillage and crop rotation were observed on the soil porosity (P < 0.01) and the soil water content (P < 0.05). The porosity for the MFM and the MWS, was higher under the CT whereas for the MWM and the MWS, it was higher under the no-till. However, the greatest porosity was under the MWS. Whilst the no-till significantly increased (P < 0.05) the soil water content compared to the CT; the greatest soil water content was observed when the no-till was combined with the MWM rotations. The soil organic carbon (SOC) was increased more (P < 0.05) by the no-till than the CT, and the MFM consistently had the least SOC compared with the rest of the crop rotations, at all the sampling depths (0–5, 5–10 and 10–20 cm). The soil bulk density negatively correlated with the soil porosity and the soil water content, whereas the porosity positively correlated with the soil water content. The study concluded that the crop rotations, the MWM and the MWS under the no-till coupled with the residue retention improved the soil porosity and the soil water content levels the most.
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Zou, C., R. Sands, G. Buchan i I. Hudson. "Least limiting water range: a potential indicator of physical quality of forest soils". Soil Research 38, nr 5 (2000): 947. http://dx.doi.org/10.1071/sr99108.
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The interactions of the 4 basic soil physical properties—volumetric water content, matric potential, soil strength, and air-filled porosity—were investigated over a range of contrasting textures and for 3 compaction levels of 4 forest soils in New Zealand, using linear and non-linear regression methods. Relationships among these properties depended on texture and bulk density. Soil compaction increased volumetric water contents at field capacity, at wilting point, and at the water contents associated with restraining soil strength values, but decreased the water content when air-filled porosity was limiting. The integrated effect of matric potential, air-filled porosity, and soil strength on plant growth was described by the single parameter, least limiting water range (LLWR). LLWR defines a range in soil water content within which plant growth is least likely to be limited by the availability of water and air in soil and the soil strength. Soil compaction narrowed or decreased LLWR in most cases. In coarse sandy soil, initial compaction increased LLWR, but further compaction decreased LLWR. LLWR is sensitive to variations in forest management practices and is a potential indicator of soil physical condition for sustainable forest management.
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Opeyemi, Akintola, Bodede Adewunmi i Abiola Oluwaseyi. "Physical and Chemical Properties of Soils in Gambari Forest Reserve Near Ibadan, South Western Nigeria." Journal of Bioresource Management 7, nr 2 (1.06.2020): 57–67. http://dx.doi.org/10.35691/jbm.0202.0132.
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The different features of soil greatly affect the flora and vegetative diversity of a forest. The physical and chemical characteristics of soils in Onigambari Forest Reserve were evaluated to assess the fertility and productivity status of the soils. Fifteen soil samples collected from different sample locations were analyzed for soil texture (sand, silt and clay), bulk density, porosity, pH, organic matter, total nitrogen, available phosphorus, exchangeable bases (Na, K, Ca and Mg) and available micronutrients (Zn, Cu, Fe and Mn). Texturally, the studied soils were loamy sand and sandy loam with percentage of sands (71.2-84.2 %), silts (7.4-10.4 %) and clay (6.4-19.4 %). The bulk density of the soils was 1.61-1.83 % while the porosity of the soils ranged from 35.2-44.1 %. The slightly acidic to neutral soil pH (5.90 - 6.60) and medium organic matter content (1.68 -2.60 %) suggest adequate level of soil nutrients. The soils had high total nitrogen (0.35 -0.65 %) and available phosphorus contents between 10.98 and 18.22mg/kg.
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Dorel, M., J. Roger-Estrade, H. Manichon i B. Delvaux. "Porosity and soil water properties of Caribbean volcanic ash soils". Soil Use and Management 16, nr 2 (19.01.2006): 133–40. http://dx.doi.org/10.1111/j.1475-2743.2000.tb00188.x.
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Abraha, Tesfamariam i Truter. "Can a Blend of Amendments be an Important Component of a Rehabilitation Strategy for Surface Coal Mined Soils?" Sustainability 11, nr 16 (8.08.2019): 4297. http://dx.doi.org/10.3390/su11164297.
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Soil compaction impedes plant growth by negatively affecting water infiltration, soil aeration, access to soil water and nutrients, and consequently restricts root development. Previous studies to alleviate such problems in rehabilitated mine soils using a single amendment material did not provide a long lasting solution. The aim of the study was to quantify the role of different amendments in alleviating selected soil hydraulic properties. Five single amendment materials and three different blends of amendments were mixed thoroughly with degraded mine soil in a 1:3 (amendment:soil) ratio and packed in columns. Two additional unamended soils with different bulk densities were included as benchmarks. In general, the application of amendments reduced bulk density (BD) by 4–20%, enhanced infiltration rate by 15–70%, increased porosity by 5–35% and increased plant available water (PAW) by 9–33% compared with the unamended soils. Between amendments, the blends of amendments reduced BD by 9–16%, enhanced infiltration rate by 17–59%, increased porosity by 6–32%, and PAW by 4–28% compared with single amendments. The study showed that a blend of amendments have better soil restoration capacity through improving porosity, infiltration rate and plant available water. A blend of amendments therefore has the potential to be a sustainable and an important component of a rehabilitation strategy for surface coal mined soils.
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Addison, B., M. Boyes i P. L. Singleton. "Differences in particle density between field-moist and oven-dry samples from Allophanic Soils". Soil Research 37, nr 5 (1999): 965. http://dx.doi.org/10.1071/sr98116.
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Particle density is used to calculate total soil porosity and related measurements such as macroporosity and water storage capacity. Methods for measuring particle density often advise using dry samples. This study measured particle density by displacement of water using both field-moist and oven-dry samples from 4 New Zealand Allophanic Soils. There were significant differences in particle density between the 2 methods. Oven-dry samples under-estimated particle density by up to 0.33 Mg/m 3 and as a result, calculations of porosity were under-estimated by up to 0.05 m 3/m 3 . Under-estimation of porosity can result in incorrect interpretation of a soil's aeration and water holding status. Allophanic Soils are known to undergo irreversible physical changes on drying and it is likely that these changes caused the difference in measurements. Only field-moist samples should be used to determine particle density of Allophanic Soils to ensure accurate calculation of soil porosity.
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Charoonphong, Wanichaya, i Nathawut Thanee. "Effect of Habitat Types on the Physical and Chemical Properties of Soils in Sakaerat Environmental Research Station, Thailand". Advanced Materials Research 864-867 (grudzień 2013): 44–48. http://dx.doi.org/10.4028/www.scientific.net/amr.864-867.44.
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Certain ecological factors were investigated for three plant forest habitat types; dry evergreen (DEF), dry dipterocarp (DDF) and ecotone (ECO) at the Sakaerat Environmental Research Station (SERS). The effects of seven habitat types on the physical and chemical properties of soils were investigated. Samples were collected monthly from June 2007 to July 2008. Values for bulk density, porosity, soil pH, soil temperature, total nitrogen and organic matter showed significant differences (p<0.05) between habitat types. The ecotone soil had the highest bulk density and the dry evergreen forest soil the highest soil porosity, while soils from both habitat types were found to be acidic. The dry evergreen forest also had the highest concentrations of organic matter and total nitrogen content, but the lowest concentrations of phosphorus and potassium.
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Burr-Hersey, Jasmine E., Karl Ritz, Glyn A. Bengough i Sacha J. Mooney. "Reorganisation of rhizosphere soil pore structure by wild plant species in compacted soils". Journal of Experimental Botany 71, nr 19 (15.07.2020): 6107–15. http://dx.doi.org/10.1093/jxb/eraa323.
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Abstract Soil compaction represents a major impediment to plant growth, yet wild plants are often observed thriving in soil of high bulk density in non-agricultural settings. We analysed the root growth of three non-cultivated species often found growing in compacted soils in the natural environment. Plants of ribwort plantain (Plantago lanceolata), dandelion (Taraxacum officinale), and spear thistle (Cirsium vulgare) were grown for 28 d in a sandy loam soil compacted to 1.8 g cm–3 with a penetration resistance of 1.55 MPa. X-Ray computed tomography was used to observe root architecture in situ and to visualise changes in rhizosphere porosity (at a resolution of 35 μm) at 14 d and 28 d after sowing. Porosity of the soil was analysed within four incremental zones up to 420 μm from the root surface. In all species, the porosity of the rhizosphere was greatest closest to the root and decreased with distance from the root surface. There were significant differences in rhizosphere porosity between the three species, with Cirsium plants exhibiting the greatest structural genesis across all rhizosphere zones. This creation of pore space indicates that plants can self-remediate compacted soil via localised structural reorganisation in the rhizosphere, which has potential functional implications for both plant and soil.
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Yi, Shuhua, Yujie He, Xinlei Guo, Jianjun Chen, Qingbai Wu, Yu Qin i Yongjian Ding. "The physical properties of coarse-fragment soils and their effects on permafrost dynamics: a case study on the central Qinghai–Tibetan Plateau". Cryosphere 12, nr 9 (27.09.2018): 3067–83. http://dx.doi.org/10.5194/tc-12-3067-2018.
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Abstract. Soils on the Qinghai–Tibetan Plateau (QTP) have distinct physical properties from agricultural soils due to weak weathering and strong erosion. These properties might affect permafrost dynamics. However, few studies have investigated both quantitatively. In this study, we selected a permafrost site on the central region of the QTP and excavated soil samples down to 200 cm. We measured soil porosity, thermal conductivity, saturated hydraulic conductivity, and matric potential in the laboratory. Finally, we ran a simulation model replacing default sand or loam parameters with different combinations of these measured parameters. Our results showed that the mass of coarse fragments in the soil samples (diameter >2 mm) was ∼55 % on average, soil porosity was less than 0.3 m3 m−3, saturated hydraulic conductivity ranged from 0.004 to 0.03 mm s−1, and saturated matric potential ranged from −14 to −604 mm. When default sand or loam parameters in the model were substituted with these measured values, the errors of soil temperature, soil liquid water content, active layer depth, and permafrost lower boundary depth were reduced (e.g., the root mean square errors of active layer depths simulated using measured parameters versus the default sand or loam parameters were about 0.28, 1.06, and 1.83 m). Among the measured parameters, porosity played a dominant role in reducing model errors and was typically much smaller than for soil textures used in land surface models. We also demonstrated that soil water dynamic processes should be considered, rather than using static properties under frozen and unfrozen soil states as in most permafrost models. We conclude that it is necessary to consider the distinct physical properties of coarse-fragment soils and water dynamics when simulating permafrost dynamics of the QTP. Thus it is important to develop methods for systematic measurement of physical properties of coarse-fragment soils and to develop a related spatial data set for porosity.
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Rieu, Michel, i Garrison Sposito. "Fractal Fragmentation, Soil Porosity, and Soil Water Properties: I. Theory". Soil Science Society of America Journal 55, nr 5 (wrzesień 1991): 1231–38. http://dx.doi.org/10.2136/sssaj1991.03615995005500050006x.
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Rieu, Michel, i Garrison Sposito. "Fractal Fragmentation, Soil Porosity, and Soil Water Properties: II. Applications". Soil Science Society of America Journal 55, nr 5 (wrzesień 1991): 1239–44. http://dx.doi.org/10.2136/sssaj1991.03615995005500050007x.
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McCarthy, Kevin P., i Kirk W. Brown. "Soil Gas Permeability as Influenced by Soil Gas-Filled Porosity". Soil Science Society of America Journal 56, nr 4 (lipiec 1992): 997–1003. http://dx.doi.org/10.2136/sssaj1992.03615995005600040001x.
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Derdour, H., M. R. Laverdière i D. A. Angers. "Caractérisation de l'espace poral d'un sol argileux: effets de ses constituants et du travail du sol". Canadian Journal of Soil Science 73, nr 3 (1.08.1993): 299–307. http://dx.doi.org/10.4141/cjss93-032.
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The objective of this study was to compare the effects of three tillage treatments and soil constituents on soil porosity characteristics. The experiment was initiated in the fall of 1987 on a Kamouraska clay (Orthic Humic Gleysol). Moldboard plowing, chisel plowing and no-till were compared during the fourth growing season of a continuous barley (Hordeum vulgare L.) system. Surface soil samples were taken in late May 1991 after seeding and at the beginning of October before primary tillage. Soil porosity was characterized by measuring the total porosity and its textural, structural and shrinkage components. The tillage treatments had no significant effect on total porosity. In May, however, the structural porosity was 25% larger under moldboard plowing than under no-till. On average for the two sampling dates, the interclod porosity was 51% larger under moldboard plowing than under no-till. In addition, this component of the structural porosity increased during the growing season under all treatments. In May, the shrinkage porosity decreased progressively from moldboard plowing to chisel and to no-till whereas the reverse trend was observed in the fall. Textural porosity was positively correlated with clay and organic carbon contents. This study shows that tillage affects mainly the structural porosity and in particular its interclod and shrinkage components. Key words: Tillage, total porosity, structural porosity, textural porosity, shrinkage porosity
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Rosli, Najmiah, Rosli Saad, Nazrin Rahman i Nur Azwin Ismail. "Soft soils: A study on their electrical resistivity values and geotechnical properties (porosity, SPT and particle size distribution)". Warta Geologi 46, nr 3 (31.12.2020): 186–90. http://dx.doi.org/10.7186/wg463202002.
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Soft soils pose abundant engineering issues due to its low bearing capacity and shear strength. Comprehensive study on soft soil’s physical properties such as shear strength and ability to store water (porosity) could help in devising the optimum ground improvements and foundations techniques. Therefore, physical properties of soft marine clay in Nibong Tebal were thoroughly studied using 2-Dimensional Resistivity Imaging (2-DRI) method in conjunction with porosity measurements, standard penetration test values (SPT-n) and particle size distribution (PSD) analysis. The 2-DRI profile depicts three lithologies, which are unsaturated topsoil, saturated soft clayey soil and saturated sandy soil in the area. The soft soil extends up to 32 m in thickness where it overlies the sandy layer and could be correlated back to lithology profile from borehole record. Additionally, soil samples were collected at three locations along the survey line for porosity measurements via saturation porosimetry method. The samples demonstrate that the clay layer has a very large porosity range and signifies that the soil will compress tremendously under load. On the other hand, SPT-N values of the soft clay is also very low; thus, could be classed as very soft to soft cohesive soil with very low shear strength as compared to a higher range SPT-n values of the sandy layer. The PSD result also compliments the 2-DRI, porosity and SPT results to show distinct differences between topsoil and the soft clay layer in terms of the presence of fine grains. These results further indicate that the thick upper layer is not capable of bearing immense loads such as high-rise infrastructures due to the soil’s high porosity and low shear strength. Hence, the area must undergo ground remediations prior to any infrastructure developments on the land.