Influence of land management on soil erosion, connectivity, and sediment delivery in agricultural catchments: Closing the sediment budget

Abstract

Agricultural land, and arable farming in particular, is commonly associated with increased soil erosion risk. Such systems are most vulnerable during low groundcover periods, but downstream delivery is ultimately controlled by connectivity. This study provides a catchment‐scale sediment budget integrating three discrete but complementary investigations spanning different temporal and spatial scales. The first gives details on suspended sediment fluxes at the catchment outlet (2009–2012). The second provenances sources of fluxes using quantitative sediment fingerprinting. The third sets recent data in a multidecadal (60‐year) context using radiometric (137Cs) field‐scale soil loss estimates. The catchment observatory (11 km2) is low relief with predominantly well‐drained soils and dominated by spring‐sown cereal cropping through the study period. Modelling 137Cs inventory losses across 30 fields provided a catchment‐wide mean soil loss of 2.0 Mg ha−1 yr−1. Although such rates are not atypical of intensively managed agriculture across Europe, they are considerably higher than contemporary sediment export yields of 0.12 Mg ha−1 yr−1 of which fingerprinting revealed that contemporary slope erosion contributed less than 25% (0.03 Mg ha−1 yr−1). No evidence of floodplain or in‐channel sediment storage was consistent with disconnectivity. Instead, it is hypothesised that soil loss is associated with coextraction from root crop harvesting of previously widespread sugar beet crops. Considering that the highest mass‐specific 137Cs concentration occurred during the 1960s, there appears to have been significant depletion of the cumulative 137Cs inventory where root crop harvesting occurred as compared with atmospheric fallout ‘reference sites.' The study highlights the value of multiple methodologies when seeking to understand legacy issues within agricultural catchment settings.

Benchmarking a decade of holistic agro-environmental studies within the Agricultural Catchments Programme

“…The key controls for suspended sediment transport are soil type and land use. For example, arable farming on low permeability soils was particularly prone to sediment loss (Sherriff et al, 2019). The pathway for this transport was primarily through surface runoff driven by rainfall events, and thus catchment soil erosion risk can be classified according to soil drainage characteristics and land-use type (Sherriff et al, 2019).…”

“…For example, arable farming on low permeability soils was particularly prone to sediment loss (Sherriff et al, 2019). The pathway for this transport was primarily through surface runoff driven by rainfall events, and thus catchment soil erosion risk can be classified according to soil drainage characteristics and land-use type (Sherriff et al, 2019). Suspended sediment export from five of the six ACP catchments was low in comparison to values for the UK and mainland Europe.…”

Comparison of observed and DEM-driven field-to-river routing of flow from eroding fields in an arable lowland catchment

“…Harvey, 2002Harvey, , 2012Shook et al, 2021); alpine environments, which often involve debris flow activity (Berger et al, 2011;Cavalli et al, 2013;Croke et al, 2013;Heckman and Schwanghart, 2013;Turley et al, 2021); forested catchments and the role of roads and culverts (Galia et al, 2017); channel and floodplain relationships (Hooke, 2003;Sandercock and Hooke, 2011) and connectivity in semi-arid environments (Lesschen et al, 2009;Medeiros et al, 2010). Temperate lowland arable catchments have been somewhat neglected, though with some notable exceptions: Alder et al, 2015;Couturier et al, 2013;Gascuel-Odoux et al, 2009;Delmas et al, 2012;Sherriff et al, 2019;Souchere et al, 1998. In such catchments, each LE encountered by field-to-river flow and transported sediment may be located within a spectrum which ranges from the wholly natural in origin (e.g. the planform convergence of coarse-scale topography) to the wholly anthropogenic (e.g.…”

Quantified Benefits of Cultivating Day-Lily (Hemerocallis citrina) Hedgerows over Multiple Years on Sloped Red-Soil Farmland, Southern China

“…Serious soil erosion on sloped farmland and ecological decline have resulted in environmental deterioration and reductions in the potential productivity of the soil (Zhao et al 2013;Huang and Zhao 2014;Huang 2017). Many studies have shown that other than rainfall characteristics, soil management practices are the primary factors influencing runoff generation and soil erosion (Truman et al 2007;Girmay et al 2009;Sherriff et al 2019). In order to promote the development of more sustainable agricultural practices on sloped farmland in this region, it is important to examine and implement effective soil management practices such as soil and water conversation (SWC) measures.…”