<p>Soil organic carbon (OC) is one of the most important
terrestrial carbon pools and plays a major role in climate regulation, water
quality, provisional services, and numerous other ecosystem functions. The
conversion of natural vegetation and the supporting soil to intensively managed
agricultural systems put soil at risk for loss due to erosion and enhanced
microbial degradation with loss rates increased by orders of magnitude above
the pre-managed system. The process has negatively impacted agricultural
productivity on hillslopes by diminishing soil health, as well as the quality
of stream water and coastal aquatic environments, and it is an important but as
of yet poorly quantified factor in the region’s terrestrial C budgets. There
have been substantial debates on the role of erosional and depositional
processes on the landscape as a control on exchange of C between the land
surface and the atmosphere. A central aspect of the debate stems from the
limited data regarding the fate of soil erosion-induced transport of OC through
stages of detachment and splash, transport and redistribution, deposition and
burial. The overarching purpose of this thesis is to evaluate how dynamic
patterns of soil OC erosion due to intensive agricultural management influences
soil aggregate strength, the chemical nature of mobilized organic particles,
and connectivity and sourcing between hillslope and streams. Using both
simulated and natural, short-term, event-based erosive rainfall processes, with
a multiproxy geochemical approach, we attempt to develop a comprehensive
understanding of how upland watershed mechanistic controls soil movement and
associated chemical alterations to the material exported through dissected
segments from hillslope to the fluvial network. </p>
<p>Our results demonstrate that erosive processes on
hillslope connects between terrestrial sources to receiving potential
deposition settings, actively ‘filter’ soil aggregates and particles and
associated OC at each erosional stage (i.e., detachment and transport
downhill/downstream), with distinct geochemistry in low relief and poorly
drained agricultural systems, like the CCW. Complex interactions among tillage
intensity, tillage practice-induced, oriented surface roughness, and
storm-induced hydrological connectivity, that potentially impact the fate of
these transported OC upon decomposition, deposition and burial, and have
important implications for predicting landscape level heterogeneity in surface
and buried soil chemistry upon mobilization and burial, as well as the dynamics
of sourcing and transformation of material exported to inland water systems.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/15062379 |
| Date | 28 July 2021 |
| Creators | Tingyu Hou (11191914) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/Erosion_and_Mobilization_Controls_on_Soil_Organic_Geochemistry_Form_and_Flux_within_Intensively_Managed_Agricultural_Landscapes/15062379 |
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