Effect of salinity on soil structure and soil hydraulic characteristics

2020 ◽  
pp. 1-12
Author(s):  
Shengqiang Tang ◽  
Dongli She ◽  
Hongde Wang
Keyword(s):  
Soil Salinity ◽  
Soil Structure ◽  
Hydraulic Properties ◽  
Saline Water ◽  
Silty Clay ◽  
Silt Loam ◽  
Aggregate Formation ◽  
Soil Columns ◽  
Retention Capacity ◽  
Primary Particles

Revealing the influences of soil salinity on soil structure and hydraulic properties contributes to understanding the mechanism of salinity restraining rehabilitation of saline sodic soil in coastal area. After being passed through a 1 mm sieve, silt loam and silty clay were irrigated with saline water to achieve different soil salinities to highlight the effect of irrigation salinity on aggregate formation from primary particles. Three irrigation events with different saline water were conducted in the same 2 mo interval in soil columns; the soil columns were subjected to natural evaporation during the interval. The soil salinity, soil structure, soil–water characteristic curve, and saturated hydraulic conductivity (Ks) results were determined after the end of the third drying subprocess. The results showed that the proportion of water-stable macroaggregates (0.25–2 mm) in the silt loam and silty clay increased as the soil salt content (SSC) increased. Under the same matric suction, the retention capacity and plant-available water capacity (PAWC) of the silt loam first increased and then decreased, with the SSC increasing to a maximum of approximately 14.5 g kg−1. The retention capacity of the silty clay increased with the SSC, whereas the PAWC decreased with the SSC. The Ks of the silt loam increased with SSC. This study reveals the effects of soil salinity on aggregate formation from primary particles in wetting–drying cycles and describes the corresponding changes in hydraulic properties, which influence the rehabilitation of saline sodic soils in coastal areas.

Influence of soil structure on sulfate leaching from a silt loam

Soil Research ◽  
1992 ◽  
Vol 30 (4) ◽  
pp. 443 ◽  
Author(s):  
CDA Mclay ◽  
KC Cameron ◽  
RG Mclaren
Keyword(s):  
Soil Structure ◽  
Packed Column ◽  
Breakthrough Curves ◽  
Natural Soil ◽  
Silt Loam ◽  
Soil Columns ◽  
Undisturbed Soil ◽  
Soil Monolith ◽  
Sulfate Leaching ◽  
Soil Lysimeters

The influence of soil structure on sulfate leaching from a silt loam soil was assessed by comparing the results of leaching experiments conducted using undisturbed soil monolith lysimeters and re-packed soil columns. A pulse application of sulfate solution was leached through both soil systems under non-ponded infiltration conditions. Breakthrough curves (BTCs) from the undisturbed soil lysimeters were poly-modal compared with the uni-modal curves observed in re-packed column experiments. The poly-modal BTC is considered to result from sulfate leached through isolated porosity regions within the undisturbed soil monolith. Sulfate leaching rates were faster through the undisturbed soil lysimeters and this was attributed to solute transport through the natural soil macropore system, which is retained in the undisturbed soil but lost in the repacked soil columns. Leaching through soil macropores therefore can result in considerable losses of sulfur from silt loam textured soils.

The impact of freeze-thaw-cycles on soil structure and soil hydraulic properties

2021 ◽  
Author(s):  
Frederic Leuther ◽  
Steffen Schlüter
Keyword(s):  
Soil Structure ◽  
Hydraulic Properties ◽  
Initial Structure ◽  
Silty Clay ◽  
Soil Hydraulic Properties ◽  
Pore System ◽  
Undisturbed Soil ◽  
Freeze Thaw ◽  
Soil Hydraulic ◽  
The Impact

<p>The ploughing of soils drastically alters soil structure and at the same time reduces its stability against external stresses. A fragmentation of these artificially produced soil clods during winter time is often observed in areas with air temperatures fluctuating around the freezing point. In this study, the cumulative effects of multiple freeze-thaw cycles (FTCs) on soil structure and soil hydraulic properties were analyzed for two different soil textures, a silty clay loam with a substantial amount of swelling clay minerals and a silty loam with less swell/shrink dynamics. The soil material was brought into two different initial states: (i) undisturbed soil cores taken from the topsoil from a grassland, and (ii) cylinders repacked with soil clods taken from a ploughed field nearby. FTCs were simulated under controlled conditions in the lab, changes in soil structure ≥48 µm were regularly recorded using X-ray µCT. After 19 FTCs, the impact on hydraulic properties were measured and the resolution of structural characteristics were increased to 10 µm by subsampling.</p><p>The effect of FTC on soil structure was found to be dependent on the initial structure, soil texture and number of FTCs. Freezing and thawing induced a consolidation of the repacked soil clods taken from both field sites, resulting in a systematic reduction in pore sizes and macro-pore connectivity. The macro-pore system of the undisturbed samples was only slightly affected. Fragmentation of soil elements larger than 0.8 to 1.2 mm increased the connectivity of pores smaller than 0.5 to 0.8 mm. Frost action increased the unsaturated hydraulic conductivity of all treatments, while the water retention was only slightly affected. This leads to the conclusion that multiple FTCs enforces a well-connected meso-pore system at the expense of a fragile macro-pore system. A change in soil structure that benefits farmers but could be reduced in the face of milder winters due to global warming.</p>

Chloride and Lithium Transport in Large Arrays of Undisturbed Silt Loam and Sandy Loam Soil Columns

2004 ◽  
Vol 3 (1) ◽  
pp. 316
Author(s):  
M. Saleem Akhtar ◽  
Tammo S. Steenhuis ◽  
Brian K. Richards ◽  
Murray B. McBride
Keyword(s):  
Sandy Loam ◽  
Sandy Loam Soil ◽  
Silt Loam ◽  
Soil Columns ◽  
Lithium Transport ◽  
Loam Soil

Analysis of Reinforced Concrete Culvert considering Concrete Creep and Shrinkage

1996 ◽  
Vol 1541 (1) ◽  
pp. 120-126
Author(s):  
Charles J. Oswald
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Cross Sections ◽  
Soil Structure ◽  
Silty Clay ◽  
Soil Pressure ◽  
Concrete Creep ◽  
Long Span ◽  
Creep And Shrinkage ◽  
Good Agreement

Measurements made on a long span reinforced concrete arch culvert under 7.3 m (24 ft) of silty clay backfill were compared with results from finite-element analyses of the soil-structure system using the CANDE finite-element code. The culvert strains and deflections and the soil pressure on the culvert were measured during construction and during the following 2.5 years at three instrumented cross sections. The CANDE program was modified to account for the effects of concrete creep and shrinkage strains after it was noted that the measured postconstruction culvert deflection and strains increased significantly whereas the measured soil pressure on the culvert remained relatively constant. Good agreement was generally obtained between measured and calculated values of the culvert strain and deflection and the soil pressure during the entire monitoring period after the code was modified.

scholarly journals Escherichia coli Contamination of Vegetables Grown in Soils Fertilized with Noncomposted Bovine Manure: Garden-Scale Studies

2004 ◽  
Vol 70 (11) ◽  
pp. 6420-6427 ◽  
Author(s):  
Steven C. Ingham ◽  
Jill A. Losinski ◽  
Matthew P. Andrews ◽  
Jane E. Breuer ◽  
Jeffry R. Breuer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Tap Water ◽  
Silty Clay ◽  
Silt Loam ◽  
Silty Clay Loam ◽  
Manure Application ◽  
E Coli ◽  
Fertilized Soil ◽  
Low Levels ◽  
National Organic Program

ABSTRACT In this study we tested the validity of the National Organic Program (NOP) requirement for a ≥120-day interval between application of noncomposted manure and harvesting of vegetables grown in manure-fertilized soil. Noncomposted bovine manure was applied to 9.3-m2 plots at three Wisconsin sites (loamy sand, silt loam, and silty clay loam) prior to spring and summer planting of carrots, radishes, and lettuce. Soil and washed (30 s under running tap water) vegetables were analyzed for indigenous Escherichia coli. Within 90 days, the level of E. coli in manure-fertilized soil generally decreased by about 3 log CFU/g from initial levels of 4.2 to 4.4 log CFU/g. Low levels of E. coli generally persisted in manure-fertilized soil for more than 100 days and were detected in enriched soil from all three sites 132 to 168 days after manure application. For carrots and lettuce, at least one enrichment-negative sample was obtained ≤100 days after manure application for 63 and 88% of the treatments, respectively. The current ≥120-day limit provided an even greater likelihood of not detecting E. coli on carrots (≥1 enrichment-negative result for 100% of the treatments). The rapid maturation of radishes prevented conclusive evaluation of a 100- or 120-day application-to-harvest interval. The absolute absence of E. coli from vegetables harvested from manure-fertilized Wisconsin soils may not be ensured solely by adherence to the NOP ≥120-day limit. Unless pathogens are far better at colonizing vegetables than indigenous E. coli strains are, it appears that the risk of contamination for vegetables grown in Wisconsin soils would be elevated only slightly by reducing the NOP requirement to ≥100 days.

Runoff losses of cyanazine and metolachlor: effects of soil type and precipitation timing

Weed Science ◽  
2006 ◽  
Vol 54 (4) ◽  
pp. 800-806 ◽  
Author(s):  
David R. Shaw ◽  
Stephen M. Schraer ◽  
Joby M. Prince ◽  
Michele Boyette ◽  
William L. Kingery
Keyword(s):  
Soil Type ◽  
Water Runoff ◽  
Soil Drying ◽  
Silty Clay ◽  
Silt Loam ◽  
Regression Analyses ◽  
Precipitation Timing ◽  
Runoff Losses

The effects of time of precipitation and soil type on runoff losses of cyanazine and metolachlor were studied using a tilted-bed, microplot system. Two silt loam soils, Bosket and Dubbs, and a Sharkey silty clay were evaluated. Rainfall (22 mm h−1) was simulated at 0, 2, and 14 days after treatment (DAT). Time of precipitation did not impact herbicide losses or any of the runoff parameters evaluated in this study. Water runoff occurred sooner and in greater quantities from the surfaces of Bosket and Dubbs silt loam soils than from the surface of Sharkey silty clay. Runoff losses of cyanazine did not vary by soil type. Soil drying produced large cracks in Sharkey silty clay, which greatly reduced runoff in this soil. Combined runoff and leachate losses were highest from Dubbs silt loam. Runoff losses of metolachlor were not affected by soil type. However, regression analyses indicated that time of precipitation and soil type interacted to affect initial metolachlor concentration. At 14 DAT, initial metolachlor concentration was highest in runoff from Sharkey soil. Time of precipitation ranked with respect to initial metolachlor concentration in runoff from Bosket and Dubbs silt loam soils were 0 > 2 > 14 DAT and 0 = 2 > 14 DAT, respectively.

Resistance to water uptake by Douglas-fir seedlings in soils of different texture

1980 ◽  
Vol 10 (4) ◽  
pp. 530-534 ◽  
Author(s):  
M.G. Dosskey ◽  
T. M. Ballard
Keyword(s):  
Water Uptake ◽  
Soil Water Potential ◽  
Large Contribution ◽  
Silty Clay ◽  
Silt Loam ◽  
Unsaturated Hydraulic Conductivity ◽  
Root Shrinkage ◽  
Upper Limits ◽  
Mycorrhizal Development ◽  
Relationship Of

Seedlings of Pseudotsugamenziesii (Mirb.) Franco were grown in fertilized silty clay, silt loam, and loamy sand in a growth chamber. Needle water potentials hardly changed as soil water potential, ψs, dropped to about −2.5 MPa. At ψs = −0.6 MPa, the effect of soil texture on water uptake rate was statistically significant (p = 0.01). Calculated water uptake resistance (from soil to foliage), R, was hardly affected by ψs between −0.5 and −1.0 MPa, but nearly doubled as ψs fell from −1.0 to −2.2 MPa. Plant water resistance is inferred to change relatively little over this range. Upper limits of soil resistance at ψs > −2.5 MPa, estimated (by Gardner's equation) for silt loam and silty clay, are too low to make a large contribution to R, or to the change in R with ψs, or to the large differences in average R among different textures at ψs values from −0.5 to −2.2 MPa. It is inferred that contact resistance, Rc, is large, varies significantly with ψs, and may vary with texture. Unsaturated hydraulic conductivity differences theoretically account for a relationship of Rc, with texture, and, together with possible root shrinkage, could account for a relationship of Rc, with ψs. Mycorrhizal development in these fertilized seedlings was too slight to justify consideration of hyphal resistance.

scholarly journals Effects of water salinity and organomineral fertilization on leaf composition and production in Passiflora edulis

2018 ◽  
Vol 22 (8) ◽  
pp. 535-540 ◽  
Author(s):  
José T. A. Souza ◽  
Járisson C. Nunes ◽  
Lourival F. Cavalcante ◽  
Juliete A. da S. Nunes ◽  
Walter E. Pereira ◽  
...  
Keyword(s):  
Potassium Chloride ◽  
Soil Salinity ◽  
Saline Water ◽  
Organic Polymer ◽  
Similar Proportion ◽  
Consumer Market ◽  
Macronutrient Composition ◽  
Passiflora Edulis ◽  
Leaf Composition ◽  
Yellow Passion Fruit

ABSTRACT An experiment was undertaken in Remígio County, Paraíba State, Brazil, from July 2013 to May 2014, in order to evaluate the effects of saline water irrigation, bovine biofertilizer, and potassium type on soil salinity, leaf macronutrient composition, and production of yellow passion fruit cv. BRS Gigante Amarelo. Treatments were distributed in randomized blocks, arranged in a 2 × 2 × 2 factorial design, with reference to electrical conductivity of the water (0.35 and 4.00 dS m-1), soil with and without bovine biofertilizer, and application of potassium chloride as a conventional treatment (KCl) and in an organic polymer-coated form, supplied monthly. Bovine biofertilizer was diluted in non-saline water (proportion, 50%) and applied via water at a volume of 6 L plant-1 one day before transplanting, and then every 90 days. The combination of saline water with bovine biofertilizer raised soil salinity to a similar proportion when comparing saline water and conventional potassium chloride with saline water and polymer-coated potassium chloride. The increase in water saline concentrations associated with both types of potassium chloride and with bovine biofertilizer elevated soil salinity from non-saline to saline. On starting to flower, plants of cv. BRS Gigante Amarelo were deficient in macronutrients other than nitrogen and potassium, but nonetheless produced fruits of an adequate mass for the consumer market.

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