The influence of surfactant and organic matter content on wetting pattern of different non-water repellent soils

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.

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.


Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3158
Author(s):  
Tomoyo Kurozumi ◽  
Yasushi Mori ◽  
Hiroaki Somura ◽  
Milagros O-How

Rice terraces in Cordillera, Philippines, a world cultural heritage site, are threatened by the risk of collapse. It is crucial to manage these rice terraces for their conservation, while simultaneously practicing traditional farming. We examined the soil environment and investigated its effects on rice terrace conservation, by focusing on the hardpan condition; infiltration process, which is related to the collapse of rice terraces; and soil nutrition conditions in these sites. Field survey and soil analysis revealed that in areas where the hardpan was not sufficiently developed and water infiltration was effectively suppressed, organic matter content was significantly high, suggesting organic matter clogging. In these rice terraces, the amounts of P, K, Ca, and Mn were significantly low, showing the mineral leaching under reductive soil conditions. Therefore, hardpan formation, rather than organic matter clogging, is essential for the suppression of infiltration and prevention of potential terrace collapse. Because hardpan formation or organic matter clogging cannot be identified from the surface of flooded rice paddies, it is difficult to identify the influencing factor. Thus, we suggest that the hard soil layer should be checked before the planting season and drainage is allowed after the cropping season in the rainy season.


Author(s):  
Vito Ferro ◽  
Vincenzo Bagarello

Field plots are often used to obtain experimental data (soil loss values corresponding to different climate, soil, topographic, crop, and management conditions) for predicting and evaluating soil erosion and sediment yield. Plots are used to study physical phenomena affecting soil detachment and transport, and their sizes are determined according to the experimental objectives and the type of data to be obtained. Studies on interrill erosion due to rainfall impact and overland flow need small plot width (2–3 m) and length (< 10 m), while studies on rill erosion require plot lengths greater than 6–13 m. Sites must be selected to represent the range of uniform slopes prevailing in the farming area under consideration. Plots equipped to study interrill and rill erosion, like those used for developing the Universal Soil Loss Equation (USLE), measure erosion from the top of a slope where runoff begins; they must be wide enough to minimize the edge or border effects and long enough to develop downslope rills. Experimental stations generally include bounded runoff plots of known rea, slope steepness, slope length, and soil type, from which both runoff and soil loss can be monitored. Once the boundaries defining the plot area are fixed, a collecting equipment must be used to catch the plot runoff. A conveyance system (H-flume or pipe) carries total runoff to a unit sampling the sediment and a storage system, such as a sequence of tanks, in which sediments are accumulated. Simple methods have been developed for estimating the mean sediment concentration of all runoff stored in a tank by using the vertical concentration profile measured on a side of the tank. When a large number of plots are equipped, the sampling of suspension and consequent oven-drying in the laboratory are highly time-consuming. For this purpose, a sampler that can extract a column of suspension, extending from the free surface to the bottom of the tank, can be used. For large plots, or where runoff volumes are high, a divisor that splits the flow into equal parts and passes one part in a storage tank as a sample can be used. Examples of these devices include the Geib multislot divisor and the Coshocton wheel. Specific equipment and procedures must be employed to detect the soil removed by rill and gully erosion. Because most of the soil organic matter is found close to the soil surface, erosion significantly decreases soil organic matter content. Several studies have demonstrated that the soil removed by erosion is 1.3–5 times richer in organic matter than the remaining soil. Soil organic matter facilitates the formation of soil aggregates, increases soil porosity, and improves soil structure, facilitating water infiltration. The removal of organic matter content can influence soil infiltration, soil structure, and soil erodibility.


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.


2018 ◽  
Author(s):  
Yu Liu ◽  
Zeng Cui ◽  
Ze Huang ◽  
Hai-Tao Miao ◽  
Gao-Lin Wu

Abstract. Litter crusts are integral components of the water budget in terrestrial ecosystems, especially in arid areas. This innovative study is to quantify the ecohydrological effectiveness of litter crusts in desert ecosystems. We focus on the positive effects of litter crusts on soil water holding capacity and water interception capacity compared with biocrusts. Litter crusts significantly increased soil organic matter, which was 2.4 times the content in biocrusts and 3.84 times the content in bare sandy lands. Higher organic matter content resulted in increased soil porosity and decreased soil bulk density. Meanwhile, soil organic matter can help to maintain maximum infiltration rates. Litter crusts significantly increased the water infiltration rate under high water supply. Our results suggested that litter crusts significantly improve soil properties, thereby influencing hydrological processes. Litter crusts play an important role in improving hydrological effectiveness and provide a microhabitat conducive to vegetation restoration in dry sandy ecosystem.


2018 ◽  
Vol 66 (3) ◽  
pp. 271-278 ◽  
Author(s):  
Nasrollah Sepehrnia ◽  
Olga Fishkis ◽  
Bernd Huwe ◽  
Jörg Bachmann

AbstractThe coupled transport of pollutants that are adsorbed to colloidal particles has always been a major topic for environmental sciences due to many unfavorable effects on soils and groundwater. This laboratory column study was conducted under saturated moisture conditions to compare the hydrophobic character of the suspended and mobilized colloids in the percolates released from a wettable subsoil and a water repellent topsoil. Both soils with different organic matter content were analyzed for wettability changes before and after leaching using sessile drop contact angles as well as water and ethanol sorptivity curves, summarized as repellency index. Hydrophobicity of the effluent suspensions was assessed using the C18 adsorption method. Water repellency level of the repellent soil decreased after leaching but remained on a lower level of water repellency, while, the wettable soil remained wettable. The leached colloids from the repellent soil were predominantly hydrophilic and the percentage of the hydrophobic colloid fraction in the effluent did not systematically changed with time. Total colloid release depended on soil carbon stock but not on soil wettability. Our results suggest that due to the respective character of transported colloids a similar co-transport mechanism for pollutants may occur which does not depend explicitly on soil wettability of the releasing horizon, but could be more affected by total SOM content. Further studies with a wider range of soils are necessary to determine if the dominant hydrophilic character of leached colloids is typical. Due to the mostly hydrophilic colloid character we conclude also that changes in wettability status, i.e. of wettable subsoil horizons due to the leachate, may not necessarily occur very fast, even when the overlaying topsoil is a repellent soil horizon with a high organic matter content.


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.


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