Soil aggregation dynamics and carbon sequestration

Abstract

Abstract:The quantity and quality of residues determine the formation and stabilization of aggregate structure for soil organic carbon (SOC) sequestration. Plant roots and residues are the primary organic skeleton to enmesh the inorganic particles together and build macro-and microaggregates while sequestering SOC. There are three major organic binding agents of aggregation: temporary (plant roots, fungal hyphae, and bacterial cells), transient (polysaccharides), and persistent (humic compounds and polymers). Conversion of natural ecosystems into agricultural lands for intensive cultivation severely depletes SOC pools. Magnitude of SOC sequestration in the soil system depends on the residence time of SOC in aggregates. Microaggregates are bound to old organic C, whereas macroaggregates contain younger organic material. Many techniques have been used to assess the SOC distribution in aggregates. Classical methods include SOC determination in aggregate fractions by wet and dry sieving of bulk soil. Isotopic methods including the determination of 13 C and 14 C with mass spectrometry are techniques to quantify the turnover and storage of organic materials in soil aggregates. Other techniques involve the use of computed tomography, X-ray scattering, and X-ray microscopy to examine the internal porosity and interaggregate attributes of macro-and microaggregates. Current state-of-knowledge has not unravelled completely the underlying complex processes involved in the sequestration, stability, dynamics, and residence times of SOC in macro-and microaggregates. There is a need to develop a unique conceptual model of aggregate hierarchy.

Microbial Extracellular Polymeric Substances: Ecological Function and Impact on Soil Aggregation

“…Aggregates are important for the improvement of soil fertility, porosity, erodibility, and agronomic productivity by influencing plant germination and root growth ( Dinel et al, 1992 ; Bronick and Lal, 2005 ). Aggregate formation involves numerous factors: vegetation, soil fauna, microorganisms, cations, and interactions between clay particles and organic matter ( Kumar et al, 2013 ). The stability of aggregates depends on their internal cohesion, pore volume, connectivity, tortuosity, and pore-wall hydrophobicity ( Chenu and Cosentino, 2011 ).…”

An improved method for determination of aggregate stability using laser diffraction

“…Soil aggregates and their stabilities play an important role in the soil environment. The literature describes the influence of different natural factors on the processes of aggregate formation (Kumar, Rawat, Singh, Singh, & Rai, ; Lehmann & Rillig, ; Lipiec, Brzezińska, Turski, Szarlip, & Frąc, ), and anthropogenic influences are commonly investigated (Glina et al, ; Makó, Csatári, Barna, Földényi, & Tóth, ; Šimanský, Polláková, Jonczak, & Jankowski, ; Świtoniak, Dąbrowski, & Łyszkiewicz, ). Information about aggregate structure is useful for soil science researchers' activities.…”

Available nutrients status in black soils of Varanasi district of eastern part of Uttar Pradesh

“…Soils of Araziline block of Varanasi district are low in available N, and medium in available P and K (Singh et al, 2016a). Conversion of natural ecosystems into agricultural lands for intensive cultivation severely depletes SOC pools (Kumar et al, 2013). Organic matter and plant residues are major sources of plant-available sulfur in the soil.…”