scholarly journals Physical and Biogeochemical Characterization of a Tropical Karstic Marsh in the Yucatan Peninsula, Mexico.

2021 ◽  
Author(s):  
Eduardo Cejudo ◽  
Daniela Ortega-Camacho ◽  
Eduardo Arturo García-Vargas ◽  
Elizabeth Hernández-Alarcón
Keyword(s):  
Ecosystem Services ◽  
High Water ◽  
Quintana Roo ◽  
Water Retention Capacity ◽  
Base Line ◽  
Retention Capacity ◽  
The North ◽  
Nutrients Cycling ◽  
Flood Regulation ◽  
Almost All

Abstract Karstic wetlands provide important ecosystem services such as maintenance of hydrological balance, flood regulation, drinking water supply and nutrients cycling. It is important to conserve and maintain karstic wetlands due to its interaction with groundwater systems and its socioeconomic relevance. The objective of this research was to generate base-line knowledge of the microtopography, hydroperiod and biogeochemical characteristics of poorly known tropical karstic marshes by testing two hypotheses, the phreatotrophic nature of tropical karstic marshes, and the alteration of its biogeochemistry by a highway dividing the marsh. The study site is located in the north of the state of Quintana Roo (Mexico), in pseudo-paludal depressions associated to fractures. The water level varied from few centimeters below the ground to more than 100 cm. We demonstrate that the wetland is groundwater-fed with differences among groundwater, interstitial and surface water in almost all parameters measured. The water is calcium bicarbonate type; the main processes occurring are recharge, evaporation and rock dissolution. Our results suggests active denitrification, low phosphates attributed to Ca- and Fe/Al-bound P, elevated alkalinity and sulfate reduction due to anaerobic conditions in water and soil. The soil reflect its sedimentary origin, the bulk density is low with very high water retention capacity. We do not have enough evidence of the highway modifying the biogeochemistry or hydrology of the marsh. These karstic wetlands provide important provisioning and supporting ecosystem services that should be studied, acknowledged and maintained.

scholarly journals PREPARATION, CHARACTERIZATION OF BIOCHAR FOR A SUSTAINABLE SOIL HEALTH

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rekha A. ◽  
Vidhya A.
Keyword(s):  
Soil Health ◽  
Physicochemical Characteristic ◽  
High Water ◽  
Exchange Capacity ◽  
Climatic Conditions ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Bet Analysis ◽  
Thermochemical Processes

Recent research suggests that biochar is a promising approach to minimize soil contamination caused by heavy metals and organic pollutants. It is also involved in the amendment of soil by altering the nutrients, pH and other factors. Through intensive literature review, this paper was aimed to better understand the selection of feedstock processes, preparation, and characterization of biochar. Wide variety of feedstock used for the biochar production based on the cost effectiveness, ease availability and they are ecofriendly to the environment. Among the thermochemical processes, pyrolysis is the promising techniques followed for the production of BC. The stabilization efficacy was mainly determined by cation exchange capacity, pH, and ash content of the biochar. The physicochemical characteristic of the biochar is analyzed using various methods such as SEM, FTIR, TGA and BET analysis. The surface area plays a major role in the metal sorption. The quality characteristics of biochar as a soil amendment varied greatly with the feedstock materials and the pyrolysis conditions. Biochar plays a great role in increasing the pH which helps the acidic soil region and its high-water retention capacity enhance the moisture level in the soil which enhances the microbial communities and its activity. Biochar becomes stabilized in the soil by interacting with soil particles. The inherent characteristics of the biochar as dictated by feedstock and pyrolysis conditions, interact with climatic conditions such as precipitation and temperature to influence how long biochar carbon remains stored in the soil. Due to its carbon sequestration in the soil, it helps in increasing the fertility of the soil and also enhances the crop yield.

Properties and Management of Allophanic Soils

2003 ◽  
Author(s):  
Anthony S. R. Juo ◽  
Kathrin Franzluebbers
Keyword(s):  
Water Content ◽  
Bulk Density ◽  
Water Retention ◽  
Field Capacity ◽  
High Water ◽  
Soil Porosity ◽  
Water Retention Capacity ◽  
Soil Taxonomy ◽  
Retention Capacity ◽  
High Soil

Allophanic soils are dark-colored young soils derived mainly from volcanic ash. These soils typically have a low bulk density (< 0.9 Mg/m3), a high water retention capacity (100% by weight at field capacity), and contain predominantly allophanes, imogolite, halloysite, and amorphous Al silicates in the clay fraction. These soils are found in small, restricted areas with volcanic activity. Worldwide, there are about 120 million ha of allophanic soils, which is about 1% of the Earth's ice-free land surface. In tropical regions, allophanic soils are among the most productive and intensively used agricultural soils. They occur in the Philippines, Indonesia, Papua New Guinea, the Caribbean and South Pacific islands, East Africa, Central America, and the Andean rim of South America. Allophanic soils are primarily Andisols and andic Inceptisols, Entisols, Mollisols, and Alfisols according to the Soil Taxonomy classification. Allophanic soils generally have a dark-colored surface soil, slippery or greasy consistency, a predominantly crumb and granular structure, and a low bulk density ranging from 0.3 to 0.8 Mg/m3. Although allophanic soils are apparently well-drained, they still have a very high water content many days after rain. When the soil is pressed between fingers, it gives a plastic, greasy, but non-sticky sensation of a silty or loamy texture. When dry, the soil loses its greasiness and becomes friable and powdery. The low bulk density of allophanic soils is closely related to the high soil porosity. For example, moderately weathered allophanic soils typically have a total porosity of 78%, with macro-, meso-, and micropores occupying 13%, 33%, and 32%, respectively. Water retained in the mesopores is readily available for plant uptake. Water retained in the micropores is held strongly by soil particles and is not readily available for plant use. The macropores provide soil aeration and facilitate water infiltration. The high water retention capacity is also associated with the high soil porosity. In allophanic soils formed under a humid climate, especially those containing large amounts of allophane, the moisture content at field capacity can be as high as 300%, calculated on a weight basis. Such extremely high values of water content seem misleading.

scholarly journals Long-term hydraulic behaviour and soil ripening processes in a dike constructed from dredged material

2019 ◽  
Vol 20 (3) ◽  
pp. 1793-1805
Author(s):  
Julia Gebert ◽  
Alexander Groengroeft
Keyword(s):  
High Water ◽  
Water Retention Capacity ◽  
Dredged Material ◽  
Test Field ◽  
Retention Capacity ◽  
Marsh Sediment ◽  
Shrinkage Cracks ◽  
Hydraulic Behaviour ◽  
Soil Ripening

Abstract Purpose Climate change necessitates heightening and strengthening of dikes, requiring large volumes of suitable soil. This study investigated soil ripening and long-term development of hydraulic behaviour of a dike constructed from slightly contaminated, partially dewatered dredged material from the Port of Hamburg under realistic conditions of construction and operation. Materials and methods Two test fields of 126 m2 each were constructed in 2004 for long-term analysis of hydraulic behaviour in combination with the possible mobilisation of contaminants. In test field 1 (MS), the 1-m-thick cover above the sand core consisted of traditionally used alluvial marsh sediment (reference), while in test field 2, the lower 0.7 m of the cover was substituted with dredged material (DM + MS). An HDPE tray below each field served the collection of bottom fluxes and hence the quantification of discharges and analysis of their chemical composition. In 2012, an excavation was carried out to inspect the development of the soil structure. Results and discussion The discharge pattern revealed three distinct phases related to the post-construction structure development and therefore physical ripening of the soils. Within a single year, bottom fluxes typically started in mid-winter and ended in late spring. The dike cover containing DM had a high water retention capacity; however, the vertically continuous primary shrinkage cracks led to higher total bottom fluxes compared to the dike constructed from MS only. System hydraulic conductivities increased by up to six orders of magnitude compared to the as-built condition before soil ripening and structuring. The dredged material maintained a reduced geochemical status for about two years after construction. After first shrinkage and intrusion of oxygen, the material changed to an oxidised state, earmarking the onset of the chemical ripening process. Oxidising conditions were sustained in the long term, seen from the absence of previously elevated ammonium concentrations in the dike seepage. Conclusions System hydraulics of the test field with dredged material were mainly determined by the covering layer of marsh sediment. After construction, the dredged material underwent physical, chemical and biological soil ripening processes, coupled to a respective change in discharge patterns, which, however, did not impair dike stability. It is recommended that soil ripening processes are induced and completed as part of the material’s pre-treatment, precluding the formation of irreversible shrinkage cracks and changeover of redox conditions after construction. The findings contribute to assessing the feasibility of the beneficial use of dredged material.

scholarly journals Testing of experimental samples of nanofibrillar cellulose in the production of lightweight coated paper

2021 ◽  
Vol 25 (2) ◽  
pp. 90-98
Author(s):  
E.T. Tyurin ◽  
◽  
A.A. Zuikov ◽  
A.I. Bondarev ◽  
L.P. Gulyanz ◽  
...  
Keyword(s):  
High Speed ◽  
Water Retention ◽  
High Water ◽  
Water Retention Capacity ◽  
Preliminary Assessment ◽  
Coated Paper ◽  
Retention Capacity ◽  
Paper Coatings ◽  
Nanofibrillar Cellulose ◽  
Coating Composition

The influence of nanofibrillar cellulose samples on the coating compositions water retention is considered. It was shown that gels of nanofibrillar cellulose and coating compositions based on them are distinguished by a high water-retention capacity during centrifugation (50.8% and 31.0% versus 17.7% with NaCMC). A preliminary assessment of the printing and technical properties of light weight coated paper (LWC) using nanofibrillar cellulose in the coating composition has been carried out. The technical characteristics of nanofibrillar cellulose have been determined, formulations of lightweight paper coatings have been developed for high-speed modern equipment.

scholarly journals Sterculia Gum: Chemical Structure, Composition and Physico-Chemical Properties

2019 ◽  
Vol 32 (1) ◽  
pp. 1-8
Author(s):  
N. Sharma ◽  
T. Sinderpal
Keyword(s):  
Drug Delivery ◽  
Wound Healing ◽  
Chemical Properties ◽  
High Water ◽  
Molecular Organization ◽  
Water Retention Capacity ◽  
Molecular Architecture ◽  
Retention Capacity ◽  
Gelling Agents ◽  
Physico Chemical

Physico-chemical properties are crucial characteristics of hydrocolloids as they decide the applicability of them. Rheology of system, flow behaviour and mechanical properties make hydrocolloids suitable for food industry. Modification of consistency or texture properties of functional polymers also controls their sensory characteristics, thereby they become significant essences such as thickener, gelling agents, foaming agent, texture modifier, viscosifier, emulsifier, stabilizer and binder. Industrial and pharmaceutical applications are also controlled by some suitable physico-chemical properties of hydrocolloids. The polysaccharide gum exudates constitute a architecturally distinct class of complex biomacromolecules having unique physico-chemical properties. Due to their good bio/tissue compatibility, non-toxicity, they are extensively used in the field of tissue engineering, drug delivery and wound healing. Chemical and molecular architecture of hydrocolloids in turn controls their physico-chemical and functional properties. Sterculia gum is a substituted rhamnogalacturonoglycan (pectic) type exudate gum used as suspending agent, gelling agents, emulsifier, bulk laxative, dental adhesive, drug delivery agent and wound healing agent. It exhibits high water retention capacity, high viscosity and least solubility. Solutions of sterculia gum are viscoelastic and thixotropic. Sterculia gum has been recommended as effective wound dressing material as it can form a intensely adhesive gel when dispersed in minimum ammount of water. Owing to wide applications and distinctive properties of sterculia gum, present work is an endeavor to summarize the molecular organization, chemical configuration and physico-chemical properties of sterculia gum and the factors affecting physico-chemical properties of sterculia gum.

Innovative green roof with high water retention and durability

2019 ◽  
Author(s):  
Thomas Cornelius Buch-Hanser ◽  
Guangli Du ◽  
David John Duffus
Keyword(s):  
Water Retention ◽  
Green Roof ◽  
Water Reservoir ◽  
Green Roofs ◽  
High Water ◽  
Water Retention Capacity ◽  
Storm Events ◽  
Concrete Element ◽  
Retention Capacity ◽  
Roof System

<p>Given the rapid increase in urban populations, combined with the effects of climate change, cities are struggling to provide green spaces to address liveability as well as adaptability to new challenges. Water retention and bio-diversity are the main advantages of green roofs. There are, however, limitations to green roofs that impede their acceptance and proliferation. There is for example uncertainty on how much water they retain during major storm events. In terms of building technology, green roofs today aren’t robust, and the risk for leakage through the roof membrane is disproportionally high when compared to the cost. A newly developed innovative green roof system with high water retention capacity and high durability will be presented. The patented prefabricated technology incorporate insulation and membrane into a single concrete element, ensuring improved robustness, quickened building times and a long term durable product. Initial indications for pricing indicate that the system is price-neutral when compared with green roofs as they are built today. The optimized structural performance obtain same loadbearing capacity, as existing systems, in spite of the relatively increased space created for water reservoir, without compromising the insulation capacity, hence the new green roof system further contribute to increased sustainability.</p>

scholarly journals Water Regulation Ecosystem Services Following Gap Formation in Fir-Beech Forests in the Dinaric Karst

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 224
Author(s):  
Urša Vilhar
Keyword(s):  
Ecosystem Services ◽  
Water Retention ◽  
Structural Characteristics ◽  
Water Retention Capacity ◽  
Water Regulation ◽  
Canopy Interception ◽  
Beech Forests ◽  
Old Growth ◽  
Retention Capacity ◽  
Dinaric Karst

This paper investigates how variation in forest structural characteristics affects the water retention capacity of gaps and forests in fir-beech forests in the Dinaric Karst. Forests are identified as a key element of the landscape for provision of pristine water resources, particularly in highly vulnerable karst aquifers characterized by rapid infiltration of recharge water, high subsurface permeability, and heterogeneous underground flow. Indicators of hydrologic fluxes (drainage flux, canopy interception, transpiration, and soil evaporation) in a large experimental gap (approximately 0.2 ha in size) and those in a nearby old-growth gap were compared over a 13-year period using the Brook90 hydrological model and their structural characteristics were analyzed. In addition, the hydrologic fluxes were also simulated for a managed forest and an old-growth forest for reference. Water regulation capacity was lowest in the experimental gap, where drainage flux accounted for 81% of precipitation and the sum of canopy interception, transpiration, and soil evaporation (evapotranspiration) accounted for 18%. This was followed by the old-growth gap, where drainage flux accounted for 78% of precipitation and evapotranspiration for 23%. Water retention capacity was highest and generally similar for both forests, where 71–72% of annual precipitation drained to the subsurface. The results of this study suggest that the creation of large canopy gaps in fir-beech forests in the Dinaric Karst results in significant and long-lasting reduction in soil and vegetation water retention capacity due to unfavorable conditions for successful natural tree regeneration. For optimal provision of water regulation ecosystem services of forests in the Dinaric Karst, small, irregularly shaped canopy gaps no larger than tree height should be created, mimicking the structural characteristics of naturally occurring gaps in old-growth forests.

scholarly journals Characterization of Some Vertisols of Different Agro-ecological Regions of India

Agropedology ◽  
2019 ◽  
Vol 27 (1) ◽  
Author(s):  
Priya Gurav ◽  
◽  
S. K. Ray ◽  
P. L. Choudhari ◽  
T. Bhattacharyya ◽  
...  
Keyword(s):  
Arid Region ◽  
High Water ◽  
Water Retention Capacity ◽  
Humid Climate ◽  
Retention Capacity ◽  
Ecological Regions ◽  
Exchange Complex ◽  
Dark Colour ◽  
Semi Arid Region ◽  
Semi Arid

Vertisols have the capacity to shrink and swell, inducing cracks and distinctive soil structure throughout the soil profile. In India they occur in various agro-ecological regions such as humid tropical (HT), sub-humid moist (SHM), sub-humid dry (SHD), semi-arid moist (SAM), semi-arid dry (SAD) and arid dry (AD) climatic environments and thus indicate an array of soils in a climosequence. In this study benchmark Vertisols, series Panjari is from sub-humid (dry), Kheriis from sub-humid (moist) region, Teligi and Akola series are from semi-arid (dry) and Nimone is from arid agro-ecological region. All the Vertisols in general are characterized by dark colour, angular to sub-angular blocky structure and clay in texture and calcareous. These soils have high bulk density and high water retention capacity. These soils have deep, wide-opened desiccation cracks at the surface which extend deep into the profiles and the depth of cracks increases with aridity. Soils of all climates are dominated by Ca2+ ion in their exchange complex throughout the depth. However, in the sub-humid climate Mg2+ ions tends to dominate in the lower horizon. Whereas the semi-arid dry (Akola) soils have high Na+ ions in their exchange complex. The soils are slightly alkaline to strongly alkaline in nature and poor in organic matter. The CEC varied from 59.3 to 68.2cmol (p+) kg-1 in soil of Panjari series which is highest followed by Teligi series profile. The calcium carbonate (CaCO3) shows gradual increase with depth in all the soil profiles, though it is preferentially accumulated in the sub-surface horizons of lower rainfall region soils.In climosequence the soils of the sub-humid region are generally Typic Haplusterts, soils of semi-arid region are Typic/Sodic/Calcic Haplusterts and soils of arid region are Sodic/ Calcic/ Aridic Haplusterts. The present study demonstrates how the soil properties of Vertisols in a different climate may help in inferring the change in climate in a geologic period.

scholarly journals Kastamonu Karaçomak Havzasının Kentsel Gelişim Alanlarında Yeraltı Suyu Beslenimi Açısından Ekolojik Etki Değerlendirme

2020 ◽  
Vol 8 (1) ◽  
pp. 186
Author(s):  
Nuriye Ebru Yıldız ◽  
Şükran Şahin
Keyword(s):  
Urban Development ◽  
Planning Process ◽  
Ecological Impact ◽  
Water Retention Capacity ◽  
Ecological Processes ◽  
Retention Capacity ◽  
The North ◽  
Before And After ◽  
Development Area ◽  
Priority Action

The aim of the study was to evaluate the ecological impact of groundwater recharging in the urban development area in the north of Kastamonu city. In this respect, the urban development area was examined in terms of water permeability, which is one of the functions of the landscape, and the ecological impact assessment was carried out in order to determine the level of change in groundwater recharging and land cover before and after urban development. With the methods used within the scope of the study, negative changes in groundwater and water retention capacity can be revealed as a result of other interventions on urbanization and landscape. On the other hand, it is important that landscape plans, where the ecological processes expressed as landscape function, including groundwater recharging and surface runoff potential, are considered as the priority action area of the multi-layered spatial planning process, rather than the investigation of the mentioned negativities after planning and/or implementation.

Utilization of Prosopis Juliflora Root Powder as a Self Curing Agent

2019 ◽  
pp. 342-345
Author(s):  
Pradeesh V ◽  
Karthikeyan S ◽  
Prabakaran D
Keyword(s):  
Water Retention ◽  
Fresh Concrete ◽  
High Water ◽  
Water Evaporation ◽  
Water Retention Capacity ◽  
Hardened Concrete ◽  
Curing Agent ◽  
Retention Capacity ◽  
Adverse Conditions ◽  
Water Holding

Curing plays a chief function in the improving the strength of concrete. The function of a self-curing agent is to save the water and to reduce the water evaporation from the concrete, and hence they increase the water retention capacity of concrete compared to the conventionally cured concrete. Prosopisjuliflora root powder is used as admixtures for self-curing concrete in this study. Prosopisjuliflora (SeemaiKaruvelam in Tamil) grows tremendously and spreads due to its mechanism to overcome adverse conditions of like drought and salt. With deep penetrating roots, it can draw water from deeper layers. Their root has high water holding capacity, so powder made from it can be used as admixture for self-curing concrete. This project involves the experimental investigation of self-curing of concrete by using Prosopisjuliflora root powder. Tests on fresh concrete and hardened concrete were conducted. From the results, we have concluded that adding prosopisjuliflora root powder as a self-curing agent in the concrete mix at various percentages, the addition of 0.75% of prosopisjuliflora root powder by the weight of cement attains the 28 days compressive strength of a conventional M25 grade concrete in 7 days.

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