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Journal ArticleDOI

Sorption of dissolved organic matter in salt-affected soils: effect of salinity, sodicity and texture.

TL;DR: The sorption of DOC (derived from mature wheat straw) was more strongly affected by SAR than by EC, andDOC sorption in salt-affected soil is more strongly controlled by CEC and Fe/Al concentration than by clay concentration per se except in sodic soils where DOC sorption is low due to the high sodium saturation of the exchange complex.
About: This article is published in Science of The Total Environment.The article was published on 2012-10-01. It has received 74 citations till now. The article focuses on the topics: Sorption & Soil water.
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TL;DR: A review of the available research on how salt affects decomposer microbial communities and carbon cycling in soil can be found in this paper, where the authors provide a brief overview and qualification of widely applied methods to assess microorganisms in soil to date.
Abstract: Salinization of soil is recognised as one of the most pressing environmental challenges to resolve for the next century. We here conduct a synoptic review of the available research on how salt affects decomposer microbial communities and carbon (C) cycling in soil. After summarizing known physiological responses of microorganisms to salinity, we provide a brief overview and qualification of a selection of widely applied methods to assess microorganisms in soil to date. The dominant approaches to characterise microbial responses to salt exposure have so far been microbial biomass and respiration measurements. We compile datasets from a selection of studies and find that (1) microbial biomass-carbon (C) per C held in soil organic matter shows no consistent pattern with long-term (field gradients) or short-term (laboratory additions) soil salinity level, and (2) respiration per soil organic C is substantially inhibited by higher salt concentrations in soil, and consistently so for both short-term and long-term salinity levels. Patterns that emerge from extra-cellular enzyme assessments are more difficult to generalize, and appear to vary with the enzyme studied, and its context. Growth based assessments of microbial responses to salinization are largely lacking. Relating the established responses of microbial respiration to that of growth could provide an estimate for how the microbial C-use efficiency would be affected by salt exposure. This would be a valuable predictor for changes in soil C sequestration. A few studies have investigated the connection between microbial tolerance to salt and the soil salinity levels, but so far results have not been conclusive. We predict that more systematic inquiries including comprehensive ranges of soil salinities will substantiate a connection between soil salinity and microbial tolerance to salt. This would confirm that salinity has a direct effect on the composition of microbial communities. While salt has been identified as one of the most powerful environmental factors to structure microbial communities in aquatic environments, no up-to-date sequence based assessments currently exist from soil. Filling this gap should be a research priority. Moreover, linking sequencing based assessments of microbial communities to their tolerance to salt would have the potential to yield biomarker sets of microbial sequences. This could provide predictive power for, e.g., the sensitivity of agricultural soils to salt exposure, and, as such, a useful tool for soil resource management. We conclude that salt exposure has a powerful influence on soil microbial communities and processes. In addition to being one of the most pressing agricultural problems to solve, this influence could also be used as an experimental probe to better understand how microorganisms control the biogeochemistry in soil. (C) 2014 Elsevier Ltd. All rights reserved. (Less)

336 citations

Journal ArticleDOI
04 Sep 2014-PLOS ONE
TL;DR: It emerged that a patchy saline soil can not contain just a single microbial community selected to withstand extreme osmotic phenomena, but many communities that can be variously correlated to one or more environmental parameters.
Abstract: In this study, the evaluation of soil characteristics was coupled with a pyrosequencing analysis of the V2-V3 16S rRNA gene region in order to investigate the bacterial community structure and diversity in the A horizon of a natural saline soil located in Sicily (Italy). The main aim of the research was to assess the organisation and diversity of microbial taxa using a spatial scale that revealed physical and chemical heterogeneity of the habitat under investigation. The results provided information on the type of distribution of different bacterial groups as a function of spatial gradients of soil salinity and pH. The analysis of bacterial 16S rRNA showed differences in bacterial composition and diversity due to a variable salt concentration in the soil. The bacterial community showed a statistically significant spatial variability. Some bacterial phyla appeared spread in the whole area, whatever the salinity gradient. It emerged therefore that a patchy saline soil can not contain just a single microbial community selected to withstand extreme osmotic phenomena, but many communities that can be variously correlated to one or more environmental parameters. Sequences have been deposited to the SRA database and can be accessed on ID Project PRJNA241061.

198 citations


Cites background from "Sorption of dissolved organic matte..."

  • ...A high concentration of salt in soil changes the availability of water and nutrients for both plants and microorganisms, and it has direct and indirect influences on soil organic matter, content, and stability [4]....

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Journal ArticleDOI
TL;DR: This review highlights growing water scarcity, the history of wastewater reuse in agriculture, and the limitations of existing studies, and takes an in-depth look at three broad areas: environmental impacts, public health impacts, and economic impacts.

107 citations

Journal ArticleDOI
TL;DR: A critical overview of the combined effects of Fe limitation and soil salinization as challenges to modern agriculture is provided and some indirect evidence is summarized that argues in favour of siderophore-producing PGPR as biofertilization agents in salinized soils.

95 citations

Journal ArticleDOI
15 Oct 2016-Geoderma
TL;DR: In this article, a set of batch adsorption-desorption experiments were conducted using pedogenic clays extracted from soils dominated by kaolinite-illite (Kaol-Ill), smectite (Smec), and allophane (Allo).

73 citations

References
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Journal ArticleDOI
TL;DR: WALKLEY as discussed by the authors presented an extension of the DEGTJAas discussed by the authorsF METHOD for determining soil organic matter, and a proposed modification of the CHROMIC ACID TITRATION METHOD.
Abstract: AN EXAMINATION OF THE DEGTJAREFF METHOD FOR DETERMINING SOIL ORGANIC MATTER, AND A PROPOSED MODIFICATION OF THE CHROMIC ACID TITRATION METHOD A. WALKLEY;I. BLACK; Soil Science

17,132 citations


"Sorption of dissolved organic matte..." refers methods in this paper

  • ...Soil organic carbon was analysed by dichromate oxidation (Walkley and Black, 1934)....

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Book
01 Jan 2012

6,880 citations

Book
01 Jan 1966
TL;DR: The Soils Around Us 2 Formation of Soils from Parent Materials 3 Soil Classification 4 Soil Architecture and Physical Properties 5 Soil Water: Characteristics and Behavior 6 Soil and the Hydrologic Cycle 7 Soil Aeration and Temperature 8 Soil Colloids: Seat of Soil Chemical and Physical Activity 9 Soil Acidity 10 Soils of Dry Regions: Alkalinity, Salinity, and Sodicity 11 Organisms and Ecology of the Soil 12 Soil Organic Matter 13 Nitrogen and Sulfur Economy of Soiles 14 Soil Ph
Abstract: 1 The Soils Around Us 2 Formation of Soils from Parent Materials 3 Soil Classification 4 Soil Architecture and Physical Properties 5 Soil Water: Characteristics and Behavior 6 Soil and the Hydrologic Cycle 7 Soil Aeration and Temperature 8 Soil Colloids: Seat of Soil Chemical and Physical Activity 9 Soil Acidity 10 Soils of Dry Regions: Alkalinity, Salinity, and Sodicity 11 Organisms and Ecology of the Soil 12 Soil Organic Matter 13 Nitrogen and Sulfur Economy of Soils 14 Soil Phosphorus and Potassium 15 Micronutrients and Other Trace Elements 16 Practical Nutrient Management 17 Soil Erosion and Its Control 18 Soils and Chemical Pollution 19 Geographic Soils Information 20 Prospects for Global Soil Quality Appendix A Soil Classification: World Resource Base Autralian and Canadian Systems Appendix B SI Units, Conversion Factors, Periodic Table of the Elements and Scentific Names of Plants Mentioned Glossary Index

6,267 citations

Journal ArticleDOI
TL;DR: In this article, the effectiveness of various binding agents at different stages in the structural organization of aggregates is described and forms the basis of a model which illustrates the architecture of an aggregate.
Abstract: Summary The water-stability of aggregates in many soils is shown to depend on organic materials. The organic binding agents have been classified into (a) transient, mainly polysaccharides, (b), temporary, roots and fungal hyphae, and (c) persistent, resistant aromatic components associated with polyvalent metal cations, and strongly sorbed polymers. The effectiveness of various binding agents at different stages in the structural organization of aggregates is described and forms the basis of a model which illustrates the architecture of an aggregate. Roots and hyphae stabilize macro-aggregates, defined as > 250 μm diameter; consequently, macroaggregation is controlled by soil management (i.e. crop rotations), as management influences the growth of plant roots, and the oxidation of organic carbon. The water-stability of micro-aggregates depends on the persistent organic binding agents and appears to be a characteristic of the soil, independent of management.

5,389 citations


"Sorption of dissolved organic matte..." refers background in this paper

  • ...Clay minerals play an important role in the stabilisation of soil organic matter (Hassink, 1997; Tisdall and Oades, 1982) by interacting with organic matter to form complexes making organic molecules less susceptible to biodegradation (Amato and Ladd, 1992; Oades, 1988)....

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01 Jan 1992
Abstract: This handbook of chemical tests for diagnostic, agricultural, and environmental purposes promotes the use of consistent methods, procedures and terminologies in soil and land surveys undertaken throughout Australia. Soil and water chemical methods include sampling and sample preparation, and measuring electrical conductivity and pH. Soil analysis includes: chloride, carbon, nitrogen, phosphorus, sulfur, gypsum, Other CABI sites 

2,597 citations


"Sorption of dissolved organic matte..." refers methods in this paper

  • ...Calcium and Mg concentrations were measured by atomic absorption spectrophotometry, and Na by flame photometry (Rayment and Higginson, 1992)....

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  • ...3 Calcium and Mg concentrations were measured by atomic absorption spectrophotometry, and Na by flame photometry (Rayment and Higginson, 1992)....

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