COMPACTION AND SETTLING OF QUEBEC SOILS IN RELATION TO THEIR SOIL-WATER PROPERTIES

1982 ◽  
Vol 62 (1) ◽  
pp. 165-175 ◽  
Author(s):  
C. R. DE KIMPE ◽  
M. BERNIER-CARDOU ◽  
P. JOLICOEUR

Twenty-one topsoils, with texture varying from sandy loam to clay and organic matter content ranging from 1.6 to 11.9%, were submitted to compaction and settling at different moisture contents where dry bulk density was determined. Under compaction, the density curve went through a maximum while a minimum was observed in the case of settling. Optimum moisture contents corresponding to these two characteristic densities were almost the same. The most important physical properties affecting soil behavior under compaction and settling were found to be water retention properties at low matric potential which themselves depended primarily on organic matter content. Samples submitted to compaction had saturated hydraulic conductivities less than 1 cm/h, while after settling, Ksat measurements ranged from 0.8 to 234 cm/h. Organic matter played an important role in reducing the effects of compaction, and moisture content alone was not sufficient to predict the best conditions for workability in the fields.

1976 ◽  
Vol 56 (3) ◽  
pp. 129-138 ◽  
Author(s):  
A. J. MACLEAN

The Cd concentration in 10 plant species grown in a neutral surface soil (0.65 ppm Cd) varied from 0.18 ppm in potato tubers to 0.99 ppm in soybean roots on a dry matter basis. Addition of 5 ppm Cd increased the concentrations in the plants markedly and they were particularly high in lettuce (10.36 ppm) and tobacco leaves (11.57 ppm). Cd concentrations tended to be lower in the edible portion (seed, fruit, tubers) than in other plant parts. Added Cd affected yields in only a few instances. But in another experiment, Cd added at a rate of 5 ppm to five soils decreased the yield of lettuce in most instances. In a comparison of results for two similarly managed sandy loam soils, nearly neutral in reaction but differing in organic matter content (2.17 vs. 15.95% organic C), the concentration of Cd was lower in lettuce grown in the soil with the higher amount of organic matter. The Cd content of the lettuce was reduced by liming some of the acid soils. Addition of Cd increased the concentration of Zn in the plants appreciably, but added Zn did not affect Cd uptake. In an incubation experiment comprising five soils, DTPA (diethylenetriamine-pentaacetic acid) extractable Cd decreased with liming of three Cd-treated acid soil samples. In comparisons of two sandy loam soils and of surface and subsoil layers of a sand, extractable Cd increased with higher amounts of soil organic matter.


Soil Research ◽  
2016 ◽  
Vol 54 (7) ◽  
pp. 880
Author(s):  
Mohammad Reza Chaichi ◽  
Marcus Turcios ◽  
Mina Rostamza

Non-ionic surfactants have been well researched as a tool to ameliorate water repellent conditions. However, few studies have evaluated the risks and benefits of non-ionic surfactant applications in wettable soil. The objective of this study was to evaluate the effects of a surfactant in modifying the wetting pattern in soils of different textures and organic matter contents. The experimental treatments consisted of (1) four different soil textures including sandy, sandy loam, sandy clay loam and silt loam, (2) four different organic matter contents (0.2, 0.7, 1.2 and 1.7% by weight), and (3) irrigation water treatments with or without surfactant (IrrigAid Gold). The experiment was carried out in Plexiglas boxes with one drip emitter under the soil surface. The results demonstrated the superiority of surfactant application on increasing water distribution in the soil profile for all soil textural classes. Silt loam texture had the highest side wetted area and wetting depth 45min after the initiation of irrigation. Upward capillary water movement and top wetted area significantly decreased in the surfactant treatment across all soil textures except in sandy soil. As organic matter content increased, top wetted area decreased. These findings clarified the potential ability of surfactant in increasing water infiltration in non-repellent soil in an in vitro system.


2013 ◽  
Vol 37 (6) ◽  
pp. 1535-1548 ◽  
Author(s):  
André da Costa ◽  
Jackson Adriano Albuquerque ◽  
Adriano da Costa ◽  
Patricia Pértile ◽  
Franciani Rodrigues da Silva

The retention and availability of water in the soil vary according to the soil characteristics and determine plant growth. Thus, the aim of this study was to evaluate water retention and availability in the soils of the State of Santa Catarina, Brazil, according to the textural class, soil class and lithology. The surface and subsurface horizons of 44 profiles were sampled in different regions of the State and different cover crops to determine field capacity, permanent wilting point, available water content, particle size, and organic matter content. Water retention and availability between the horizons were compared in a mixed model, considering the textural classes, the soil classes and lithology as fixed factors and profiles as random factors. It may be concluded that water retention is greater in silty or clayey soils and that the organic matter content is higher, especially in Humic Cambisols, Nitisols and Ferralsol developed from igneous or sedimentary rocks. Water availability is greater in loam-textured soils, with high organic matter content, especially in soils of humic character. It is lower in the sandy texture class, especially in Arenosols formed from recent alluvial deposits or in gravelly soils derived from granite. The greater water availability in the surface horizons, with more organic matter than in the subsurface layers, illustrates the importance of organic matter for water retention and availability.


1961 ◽  
Vol 7 (4) ◽  
pp. 507-513 ◽  
Author(s):  
E. Strzelczyk

This study represents an attempt to correlate the low numbers of Azotobacter in rhizosphere and root-free soils at the Central Experimental Farm, Ottawa, with the incidence of bacterial and actinomycete antagonists of this organism. Wheat, radish, and onion were grown in the greenhouse in two soils varying greatly in fertility and organic matter content, and isolations of bacteria and actinomycetes were made periodically for testing against Azotobacter. It was found that rhizosphere soil contained greater numbers of microorganisms antagonistic to Azotobacter than root-free soil. Of the three crops used wheat exerted the least effect. In all the tests numbers of antagonists were greater in the fertile Granby sandy loam than in the infertile Upland sand. The results correlated well with the Azotobacter populations in these soils as reported in the first paper of this series.


Weed Science ◽  
1999 ◽  
Vol 47 (3) ◽  
pp. 349-352 ◽  
Author(s):  
Chris H. Tingle ◽  
David R. Shaw ◽  
Patrick D. Gerard

Laboratory studies were conducted to evaluate14C-flumetsulam mobility in two Mississippi soils of varied texture and organic matter content following delays in irrigation. Mobility was evaluated using packed soil columns, 25 cm deep, under unsaturated–saturated flow conditions. Irrigation timings included 0, 3, and 5 d after flumetsulam application. Flumetsulam mobility (defined as the amount collected in leachate) decreased from 45% to no more than 20% of the applied in the Prentiss sandy loam soil when irrigation was delayed 3 or 5 d. With the Okolona soil, flumetsulam recovery in the leachate was 21, 14, and 6%, respectively when irrigation occurred 0, 3, and 5 d after application. Flumetsulam proved to be mobile when irrigation immediately followed application, with 6 to 45% recovered in the leachate from all soils evaluated. The Prentiss soil retained 6% of the applied flumetsulam in the upper 5 cm and the Okolona soil retained 22% when irrigation immediately followed flumetsulam application. When the irrigation interval was delayed at least 3 d, the Okolona soil retained 40% in the upper 5 cm, whereas the Prentiss soil retained 10%. Flumetsulam mobility was dependent on irrigation timing and soil type.


1980 ◽  
Vol 60 (1) ◽  
pp. 5-11 ◽  
Author(s):  
M. K. PRITCHARD ◽  
E. H. STOBBE

The persistence and phytotoxicity of dinitramine (n4, N4-diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2,4-diamine), fluchloralin (N-(2-chloroethyl)-2, 6-dinitro- N-propyl-4- (trifluoromethyl)aniline), profluralin (N-(cyclopropylmethyl)α,α,α-trifluoro-2, 6-dinitro-N-propyl-p-toluidine), and trifluralin (α,α,α-trifluoro-2,6-dinitro-N-N-dipropyl-p-toluidine) were compared in three Manitoba soils: sandy loam, clay loam and clay. The phytotoxicities of all chemicals decreased with increased organic matter. The phytotoxicities of the dinitroanilines were: dinitramine > trifluralin > profluralin = fluchloralin. Increased organic matter increased the persistence of trifluralin and fluchloralin. Profluralin and dinitramine persistence increased with increased clay and organic matter content. Profluralin was the most persistent chemical over all soil types. Under environmental conditions that retard dinitroaniline loss from Manitoba soils, residues of some of these herbicides may cause crop injury the year after application.


1981 ◽  
Vol 61 (2) ◽  
pp. 225-236 ◽  
Author(s):  
C. R. DE KIMPE ◽  
M. R. LAVERDIERE ◽  
J. ZIZKA

Rounding of the lands in a field involves changes in the surface horizons. The thickness of Ap horizons at various sites in corn fields varied from 15 to 41 cm. In these horizons, the organic matter content that ranged between 10 and 250 t/ha influenced the real density of the particles, the bulk density of soils with similar texture, and also the shape of the water retention curves at tensions from 0 to 1.5 MPa. Maximum available water in the Ap horizons between 33.3 kPa and 1.5 MPa varied from 0.5 to 4 cm H2O. Yield differences reached 74% while the standard deviations were generally lower than 15%. Higher yields were observed at higher, intermediate and lower sites of the fields. The differences in the yield were not entirely accounted for by the variations in the chemical and physical properties of the soils.


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