Soil Aggregate Formation PDF Download

Soil aggregate formation is essential to establish a good soil structure which can provide better functionality and serve to ecosystem services. In this study, the dynamics of soil aggregate formation in various management and ecosystems were investigated. We think the formation of different aggregates sizes varies according to the response of SOC, soil mineralogy, and hydraulic properties to soil management where re-formation of aggregates might be faster for soils containing more C, clay minerals, and improved water characteristics. The first chapter of this work aims to improve the understanding of the mechanisms responsible for soil aggregation related to soil mineralogy and C stabilization in five long-term land-uses, mainly agriculture and woodland, and grassland. Overall, the physical stabilization of SOC and soil minerals had a strong relationship with an aggregate size distribution, where the range of dominant soil particles, silt content played a vital role in these mechanisms. The second part of this work focuses on the interactions between soil carbon, hydraulic properties, and soil aggregate and pore structures. In general, higher intensity of disturbance on soil structure negatively influenced soil hydraulic properties and soil carbon content but had higher labile carbon fractions, cold-water extractable carbon, and dissolved organic carbon. The last section of this work mainly evaluates soil aggregate re-formation dynamics after disturbance in short-and long-term scales. This study was conducted in an experimental study under the impacts of conventional tillage and no-tillage management. The immediate effects of growing season, tillage, and harvest resulted in a lower proportion of larger aggregates and smaller pores, whereas long-term effects mainly influenced aggregates smaller than 2 mm. The larger soil aggregates can recover on an annual basis but aggregates smaller than 2 mm do not. In conclusion, SOC has coupled interactions with soil physical properties and soil minerals, where these associations help soil aggregate formation and stabilization. Soil disturbance due to management and erosion effects negatively influenced soil aggregate formation where larger aggregates can re-form on an annual basis but aggregates smaller than long term effects mainly influence 2 mm in different ecosystems.