Water movement in unsaturated soils as influenced by gypsum

Soil Research ◽  
1972 ◽  
Vol 10 (1) ◽  
pp. 25 ◽  
Author(s):  
ML Sharma
Keyword(s):  
Cation Exchange ◽  
Water Flow ◽  
Unsaturated Soils ◽  
Water Movement ◽  
Mean Diffusivity ◽  
Distilled Water ◽  
Exchangeable Sodium ◽  
Flow Properties ◽  
High Concentration ◽  
The Third

Three soils varying in texture and exchangeable sodium were treated either with distilled water or with a gypsum solution of 10 or 30 m-equiv./l. concentration and their water-flow properties, diffusivity (D), capillary conductivity (K), and weighted mean diffusivity (D) determined. Invariably the treatment of soils with gypsum resulted in increased D and K, the increases being more pronounced near saturation and declining with desaturation. The soil with the highest clay content and exchangeable sodium percentage (ESP) responded most. For the three soils, at the end of the third wetting and draining cycle the highest increase in D and K varied from about 3 to 15 times while D increased by a factor of 2 to 7.5. Wetting and draining cycles resulted in decreased D for all soils when distilled water was used, but only for two soils when 10 or 30 m-equiv. solutions were used. In the soil most responding to gypsum D was slightly increased with increasing number of wetting and draining cycles when gypsum solutions were used. This was due probably to rebuilding of structure by cation exchange, which was lost by slaking and dispersion during the first wetting and draining cycle. The electrolyte concentration of flowing solution did not significantly affect the water flow properties provided that the slaking and dispersion were reduced by a solution of high concentration during the process of cation exchange. At the end of the third wetting and draining cycle, 30 m-equiv. solution gave about 1.7 times higher D compared to 10 m-equiv. for the high clay, high exchangeable sodium soil. This was probably because initial structural loss caused by the first wetting and draining with 10 m-equiv. was not fully regained during subsequent wetting and draining.

Acoustic Tomography Applied to Water Flow in Unsaturated Soils

2004 ◽  
Vol 3 (1) ◽  
pp. 288
Author(s):  
Andreas Blum ◽  
Ivo Flammer ◽  
Thomas Friedli ◽  
Peter Germann
Keyword(s):  
Water Flow ◽  
Unsaturated Soils ◽  
Acoustic Tomography

SOIL AND SOLUTION pH AND SODIUM:CALCIUM RATIO: EFFECTS ON CATION EXCHANGE PROPERTIES OF A SODIUM-SATURATED CHERNOZEMIC SOIL

1984 ◽  
Vol 64 (1) ◽  
pp. 139-146
Author(s):  
THERON G. SOMMERFELDT
Keyword(s):  
Cation Exchange ◽  
Soil Ph ◽  
Irrigation Water ◽  
Polynomial Equation ◽  
Exchangeable Sodium Percentage ◽  
Exchangeable Sodium ◽  
Solution Ph ◽  
Chernozemic Soil ◽  
Sodium Percentage ◽  
Exchange Properties

The effects of soil and solution pH and Na:Ca ratio in solution on the exchangeable Na, Ca, and (Na + Ca) of a Na-saturated Dark Brown Chernozemic soil were studied. At soil pH 9.0, the exchangeable Na, Ca, and (Na + Ca) were 14.5, 25.4, and 21.8% greater than at soil pH 6.0. Solution pH (6.0–9.0) had small but statistically significant effects on the amount of Na and Ca adsorbed by the soil. The logarithm of exchangeable sodium percentage (ESP) was related to the Na fraction in the solution by a polynomial equation, log ESP = 0.93 [Na/(Na + Ca)]2 + 0.16 [Na/(Na + Ca)] + 0.82. Not only is replacement of exchangeable Na with Ca important in the reclamation of this soil, should it become sodic and have a high pH, but also lowering of its surface charge, through lowering of its pH, would be an important factor in its reclamation. It appears impractical to reduce soil pH by applying acidified irrigation water. Acidic amendments such as gypsum and sulfur may be more suitable. Key words: Cation exchange, solution pH, soil pH

scholarly journals Monitoring infiltration and subsurface stormflow in layered slope deposits with 3D ERT and hydrometric measurements – the capillary barrier effect as crucial factor

2017 ◽  
Author(s):  
Rico Hübner ◽  
Thomas Günther ◽  
Katja Heller ◽  
Ursula Noell ◽  
Arno Kleber
Keyword(s):  
Water Flow ◽  
Water Movement ◽  
Basal Layer ◽  
Organic Layer ◽  
Barrier Effect ◽  
Capillary Barrier ◽  
Shallow Subsurface ◽  
Layered Slope ◽  
Slope Deposits ◽  
Flow Pathways

Abstract. Identifying principles of water movement in the shallow subsurface is crucial for adequate process-based hydrological models. Hillslopes are the essential interface for water movement in catchments. The shallow subsurface on slopes typically consist of different layers with varying characteristics. The aim of this study was to draw conclusion about the infiltration behaviour, to identify water flow pathways and derive general validity about the water movement on a hillslope with periglacial slope deposits (cover beds), where the layers differ in their sedimentological and hydrological properties. Especially the described varying influence of the basal layer (LB) as impeding layer on the one hand and as a remarkable pathway for rapid subsurface stormflow on the other. We used a time lapse 3D ERT approach combined with punctual hydrometric data to trace the spreading and the progression of an irrigation plume in layered slope deposits during two irrigation experiments. This multi-technical approach enables us to connect the high spatial resolution of the 3D ERT with the high temporal resolution of the hydrometric devices. Infiltration through the uppermost layer was dominated by preferential flow, whereas the water flow in the deeper layers was mainly matrix flow. Subsurface stormflow due to impeding characteristic of the underlying layer occurs in form of "organic layer interflow" and at the interface to the first basal layer (LB1). However, the main driving factor for subsurface stormflow is the formation of a capillary barrier at the interface to the second basal layer (LB2). The capillary barrier prevents water from entering the deeper layer under unsaturated conditions and diverts the seepage water according to the slope inclination. With higher saturation the capillary barrier breaks down and water reaches the highly conductive deeper layer. This highlights the importance of the capillary barrier effect for the prevention or activation of different flow pathways under variable hydrological conditions.

scholarly journals Radio-response to leucocytes in peripheral blood of mice against gamma irradiation and their protection by Alstonia scholaris extract

2011 ◽  
Vol 26 (2) ◽  
pp. 126-133 ◽  
Author(s):  
Uma Gupta ◽  
Ranu Chaudhary ◽  
Pradeep Goyal
Keyword(s):  
Peripheral Blood ◽  
Vehicle Control ◽  
Control Group ◽  
Distilled Water ◽  
Neutrophilic Granulocytes ◽  
The Third ◽  
Alstonia Scholaris ◽  
Radiation Induced ◽  
Hematological Evaluation ◽  
Hematological Alterations

The present study deals with the protective effect of Alstonia scholaris extract against radiation-induced hematological alterations. Swiss albino male mice were selected from an inbred colony and divided into four groups. The first group received only double distilled water orally, served as vehicle control and the second group were administered the Alstonia scholaris extract at a dose of 100 mg/kg body weight per day dissolved in the double distilled water. The third group was administered the double distilled water, which served as irradiated control while the fourth group was administered the Alstonia scholaris extract once in a day for five consecutive days. Groups third and fourth were exposed to 7.5 Gy of gamma radiation after half an hour of 5th day of double distilled water or Alstonia scholaris extract administration, respectively. The animals were autopsied at 12 hours, days: 1st, 3rd, 7th, 15th, and 30th post-exposure for hematological evaluation. The extract was found to restore the total leucocytes and differential leucocytes (lymphocytes, monocytes, neutrophils, and non-neutrophilic granulocytes) count in the Alstonia scholaris extract pretreated animals as compared to the irradiated control group. The data clearly indicate that the Alstonia scholaris extract significantly reduced the deleterious bioeffects of radiation on peripheral blood.

Historical development of soil-water physics and solute transport in porous media

2007 ◽  
Vol 7 (1) ◽  
pp. 59-66 ◽  
Author(s):  
D.E. Rolston
Keyword(s):  
Porous Media ◽  
Hydraulic Conductivity ◽  
Solute Transport ◽  
Soil Water ◽  
20Th Century ◽  
Water Flow ◽  
Unsaturated Soils ◽  
Transport Processes ◽  
Transport In Porous Media ◽  
Unsaturated Hydraulic Conductivity

The science of soil-water physics and contaminant transport in porous media began a little more than a century ago. The first equation to quantify the flow of water is attributed to Darcy. The next major development for unsaturated media was made by Buckingham in 1907. Buckingham quantified the energy state of soil water based on the thermodynamic potential energy. Buckingham then introduced the concept of unsaturated hydraulic conductivity, a function of water content. The water flux as the product of the unsaturated hydraulic conductivity and the total potential gradient has become the accepted Buckingham-Darcy law. Two decades later, Richards applied the continuity equation to Buckingham's equation and obtained a general partial differential equation describing water flow in unsaturated soils. For combined water and solute transport, it had been recognized since the latter half of the 19th century that salts and water do not move uniformly. It wasn't until the middle of the 20th century that scientists began to understand the complex processes of diffusion, dispersion, and convection and to develop mathematical formulations for solute transport. Knowledge on water flow and solute transport processes has expanded greatly since the early part of the 20th century to the present.

Impact of legume component on productivity of gramineous mixtures

2020 ◽  
Author(s):  
С.М. Пакшина ◽  
С.Ф. Чесалин ◽  
В.Ф. Шаповалов ◽  
Е.В. Смольский
Keyword(s):  
Cation Exchange ◽  
Avena Sativa ◽  
Cation Exchange Capacity ◽  
Water Movement ◽  
Lolium Multiflorum ◽  
Exchange Capacity ◽  
Lupinus Luteus ◽  
N Availability ◽  
Panicum Miliaceum ◽  
Sorghum Sudanense

Полевые опыты проведены в 2011–2014 годах на опытном поле Новозыбковской сельскохозяйственной опытной станции – филиала ФНЦ кормопроизводства и агроэкологии им. В. Р. Вильямса. Цель работы — поиск способов повышения питательности грубых кормов и обоснование выбора компонентов для смешанных посевов, характеризующихся более высокой ёмкостью катионного обмена корневой системы, а также раскрытие механизма формирования урожайности. Опыты проведены на дерново-подзолистых песчаных почвах с одновидовыми и смешанными посевами кормовых трав. Одновидовые посевы состояли из овса посевного (Avena sativa L.), райграса однолетнего (Lolium multiflorum Lаm.), суданской травы (Sorghum sudanense Pers.), проса посевного (Panicum miliaceum L.). Смешанные посевы состояли из этих же культур с добавлением люпина жёлтого (Lupinus luteus L.) из семейства Бобовые (Fabaceae). Норма высева семян одновидовых и смешанных посевов кормовых культур была приблизительно равной. Нами установлено, что добавление бобового компонента в смеси кормовых культур приводило к усилению напряжённости электростатических полей вокруг корневых систем растений, ускорению движения почвенной влаги к зоне всасывания корневых волосков, повышению доступности влаги и элементов питания, урожайности посева. Отмечено, что увеличение доступности азота корневым системам бобовых культур, обусловленное фиксацией азота клубеньковыми бактериями жёлтого люпина, не компенсируется необходимым количеством калия для осуществления процесса синтеза сырого протеина, при этом происходит использование магния для создания безазотистых экстрактивных веществ (БЭВ). Результаты опытов открывают широкие возможности для решения практических задач выбора необходимого компонента к планируемому посеву кормовых культур, расчёта дозы калийного удобрения, от решения которых зависит урожайность и качество кормов. The field trial took place at the Novozybkovskaya Agricultural Experimental Station – branch of the Federal Williams Research Center of Fodder Production and Agroecology in 2011–2014. The goal of the research was to increase nutritional value of roughage and select optimal components for grass mixtures having higher cation exchange capacity of plant roots as well as to test crop yield formation. Grass monocultures and mixtures grew on sod-podzolic sandy soil. Monocultures were oats (Avena sativa L.), annual ryegrass (Lolium multiflorum Lаm.), Sudan grass (Sorghum sudanense Pers.), common millet (Panicum miliaceum L.). Grass mixtures were composed of the same crops combined with yellow lupin (Lupinus luteus L.). Seeding rates of monocultures and mixtures were approximately equal. Legume component increased cation exchange capacity, intensity of water movement to the absorption area of root hairs, water and nutrient availability, and mixture yield. Even though nitrogen-fixing bacteria improved N availability, effective crude protein synthesis required sufficient potassium amount. Also, magnesium was utilized to produce nitrogen-free extractive substances. The obtained results provided valuable information on choosing the necessary component for forage crop mixtures as well as potassium fertilization to improve forage production and quality.

The role of sodium chloride in the process of induction by lithium chloride in cells of the Rana pipiens gastrula

Development ◽  
1968 ◽  
Vol 19 (3) ◽  
pp. 387-396
Author(s):  
Lester G. Barth ◽  
Lucena J. Barth
Keyword(s):  
Sodium Chloride ◽  
Culture Medium ◽  
Rana Pipiens ◽  
Divalent Cations ◽  
Pigment Cells ◽  
Distilled Water ◽  
Sodium Ions ◽  
Monovalent Cations ◽  
High Concentration

A study of the effects of a series of monovalent cations, Li+, Na+ and K+, and a series of divalent cations, Mn2+, Ca2+ and Mg2+, upon small aggregates of cells taken from the presumptive epidermis of Rana pipiens gastrulae revealed that these ions induce nerve and pigment cells (Barth, 1965). The effectiveness of both series of ions as inductors was similar to their effects on decreasing the electrophoretic mobility of DNA as determined by Ross & Scruggs (1964). When it was found that sucrose in glass-distilled water also would induce nerve and pigment cells the role of ions as inductors came under closer scrutiny. A study of the nature of the induction by sucrose revealed that a relatively high concentration of sodium ions was necessary in the culture medium used after sucrose treatment (Barth, 1966).

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