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A new technique for hydraulic conductivity testing of expansive unsaturated soils

100%

Zakowicz S., Garbulewski K.

Zeszyty Problemowe Postępów Nauk Rolniczych

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1996

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tom 436

A number of factors are known to influence the hydraulic conductivity (K) of soils. While a large number of laboratory and field methods have been developed over the years, most of them are applicable mainly for the measurement of hydraulic properties in saturated soils. Moreover, those methods omit such factors affecting hydraulic conductivity as soil volume changes (swelling or shrinkage) and external load simulating the location of the soil tested. The purpose of this paper is to present direct and simple methods for estimation of hydraulic properties, mainly conductivity of unsaturated soils. The methods proposed are based on evaluation of soil-water potential and water outflow from a soil sample. The test methods allow the 1- and 3-dimensional stress states of the soil and pore-fluid to be monitored. The procedure allows also to monitor the changing soil moisture using the TDR technique. The modified apparatus (triaxial apparatus, consolidometer and tempe pressure cell), soils and procedures are described first, and then the results of tests are presented and reviewed. Interpretation of test results is made using the Multi-step method. Results obtained showed that the stress states simulating the location of soil affected the hydraulic parameters significantly. The test results confirmed the usefulness of the methods proposed for testing the porous medium with the geometrical changes of soil (swelling/shrinkage) considered.

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Enhancing the available water content in unsaturated soil zone using hydrogel, to improve plant growth indices

58%

Koupai J. A., Eslamian S. S., Kazemi J. A.

International Journal of Ecohydrology and Hydrobiology

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2008

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tom 08

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nr 1

The effects of hydrogels on the soil water retention characteristic curve (WRC) and on the growth indices of Ligusrum ovalifolium (an ornamental plant dominating in the landscape of central Iran) were studied. Various amounts of hydrogels (Suprab A200) were added to soil samples having different percentage of water proportional to potential evapotranspiration data. A factorial experiment was used for statistical analysis of data. The results of the soil water retention model showed that, hydrogel caused the residual water content and saturated water content to increase. Available water content increases to a maximum of about 2.3 times the control. Application of hydrogels can result in significant reduction in the required irrigation frequency particularly for coarse-textured soils. This is an important issue in arid and semi-arid regions of the world for enhancing the water management of coarse-textured soils.

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Zelazo i mangan w porowych wodach strefy nienasyconej lessu

51%

Afelt A.

Roczniki Państwowego Zakładu Higieny

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2004

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tom 55

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nr Supl.

191-196

Przedstawiono wyniki badań zawartości żelaza i manganu w wodach porowych lessu. Zawartości żelaza i manganu w porowej wodzie strefy nienasyconej lessu zależą od warunków obiegu wody w zlewni bezodpływowej oraz od układu morfologicznego utworu. Zmienność zawartości tych metali wykazała związek ze stopniem uwilgotnienia lessu.

Ograniczanie wyników

1 International Journal of Ecohydrology and Hydrobiology

1 Roczniki Państwowego Zakładu Higieny

1 Zeszyty Problemowe Postępów Nauk Rolniczych

1 Afelt A.

1 Eslamian S. S.

1 Garbulewski K.

1 Kazemi J. A.

1 Koupai J. A.

1 Zakowicz S.

1 2008

1 2004

1 1996

A new technique for hydraulic conductivity testing of expansive unsaturated soils

Enhancing the available water content in unsaturated soil zone using hydrogel, to improve plant growth indices

Zelazo i mangan w porowych wodach strefy nienasyconej lessu