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Plot layout of the six treatments showing the 8-m area managed under continuous cultivated fallow (CCF) as the sediment source area above an 8-m test area under switchgrass barrier, fescue filter strip, native species filter strip, or fallow.
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Vegetative filter strips (FS) perform poorly for reducing losses of sediment and nutrients in concentrated flow. Stiff-stemmed grass barriers (B-FS) above the FS may be a companion treatment to improve the FS performance. This study evaluated the effectiveness of warm-season switchgrass (Panicum virgatum L.) barriers planted above fescue (Festuca a...
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Context 1
... fabric to reduce 5.8 mm and a slope of 4.9 0.6%. berm erosion to nondetectable levels. Plots were designed Eighteen 1.5-by 16-m plots with six treatments replicated with an upslope 1.5-by 8-m pollutant source area managed three times were arranged in a randomized complete block under continuous cultivated fallow, above a downslope FS area design (Fig. 1). The six treatments were (i) a fescue FS, (ii) of the same size. A 3-m-wide alley was included between plots to a switchgrass barrier above a native species FS, (iii) concen- facilitate positioning a rainfall simulator (Fig. 1). Glyphosate trated flow above a fescue FS with no barrier (FS), (iv) concen- herbicide ...
Context 2
... times were arranged in a randomized complete block under continuous cultivated fallow, above a downslope FS area design (Fig. 1). The six treatments were (i) a fescue FS, (ii) of the same size. A 3-m-wide alley was included between plots to a switchgrass barrier above a native species FS, (iii) concen- facilitate positioning a rainfall simulator (Fig. 1). Glyphosate trated flow above a fescue FS with no barrier (FS), (iv) concen- herbicide (N-phosphonomethyl-glycine) was applied at 8 L trated flow above a barrier plus fescue FS (B-FS), (v) a switch- ha 1 to kill existing vegetation in the pollutant source area in grass barrier above a fescue FS, and (vi) a check managed in continuous ...
Citations
... The below-and above-ground part of the hedgerow play different role in affecting soil erosion and nutrient loss on sloping farmland by influencing the processes of sediment detachment, transportation and deposition. The dense above-ground part of the hedgerow acts as a "barrier" that not only physically intercepts the eroded sediment from the upper slopes, causing sediment deposition, but also interrupts the continuity of slope runoff, lowering the overflow velocity from uphill hedgerow and changing the runoff energy distribution on the slope (Tadesse and Morgan, 1996;Blanco-Canqui et al., 2004;Bu et al., 2008;Guo et al., 2022). In addition, the below-ground part of the hedgerow (roots) penetrates into the soil, resulting in a higher soil infiltrability and thereby presumably reducing runoff, it also reinforces the soil and enhances erosion resistance (Vannoppen et al., 2016;Liu et al., 2019;Guo et al., 2020;Shi et al., 2022). ...
... In addition, the soil chemical and physical properties were improved through the well-developed Vetiveria zizanioides roots, which acted as a small dam for storing water by strengthening the soil infiltration capacity (Ekwue and Harrilal, 2010). Consistent with previous research, hedgerow was more effective for the control of erosion than runoff (Blanco-Canqui et al., 2004;Huang et al., 2010;Xiao et al., 2012). The reduction in soil erosion attributed to hedgerow can be summarized as follows. ...
... The reduction in nutrient concentration in runoff by hedgerow may result from several reasons. The nutrients in the runoff were adsorbed by clay particles in the backwater zone and by Vetiveria zizanioides stems during passing by (Blanco-Canqui et al., 2004). Furthermore, the higher hydraulic pressure and lower runoff velocity in the backwater zone may lead to the eluviate into the soil leaching of more nutrients into soil. ...
Hedgerow is a vital soil and water conservation technology for sloping farmland that can significantly reduce erosion and nutrient loss via their above- and below-ground parts. The effect of hedgerow on erosion and nutrient loss has been widely investigated, while the respective effects of their above- and below-ground parts are still unclear. Therefore, the purple soil from the Three Gorges Reservoir Area was used, and 3 slope conditions of control check, whole hedgerow and hedgerow roots only combined with 2 slope gradients (15° and 25°) were constructed and the simulated rainfall tests were researched at 3 rainfall intensities (60, 90 and 120 mm h-1). The runoff initiation time, runoff and erosion rates, and loss of nitrogen via runoff and sediment were analysed. In comparison to the control check slope condition, it was indicated that hedgerow increased the runoff initiation time by 43.38%, decreased runoff and erosion by 15.59% and 78.37%, and decreased nitrogen loss via runoff by approximately 40% and via sediment by approximately 70% on average, respectively. The average contribution rates of the below-ground part of the hedgerow was 49.89% for the increase in runoff initiation time, 33.99% for runoff reduction, and 39.91% for erosion reduction. In addition, more than 2/3 and 58.49% of nitrogen loss reduction via runoff and sediment, respectively, was contributed by the above-ground part of the hedgerow. These results are beneficial for comprehending the control mechanism of hedgerow on soil erosion and nitrogen loss, thereby provide a scientific foundation for the sustainable and efficient utilization of soil and water resources on sloping farmland.
... Vegetation management can influence buffer strip efficacy for reducing incoming sediment loads since, for example, long grass is more prone to lodging, which can permit preferential flow routes and reduced efficacy. Incoming flow mechanisms can influence efficacy for reducing sediment loads with, for example, concentrated flows reducing efficacy (Blanco-Canqui et al., 2004;Dillaha et al., 1986;Dosskey et al., 2002). At our experimental site, however, pervasive raindrop-impacted saturation-excess overland flow has been identified as a primary mechanism for sediment mobilization and delivery, rather than concentrated runoff (Pulley & Collins, 2019). ...
Buffer strips continue to feature in the management of agricultural runoff and water pollution in many countries. Existing research has explored their efficacy for reducing environmental problems in different geoclimatic settings but, the evidence on the efficacy of different vegetation treatments is less abundant than that for other buffer strip characteristics, including width, and is more contradictory in nature. With policy targets for various environmental outcomes including water or air quality and net zero pointing to the need for conversion of agricultural land, the need for robust experimental evidence on the relative benefits of different vegetation types in buffer strips is now renewed. Our experiment used a replicated plot scale facility to compare the efficacy of 12 m wide buffer strips for controlling runoff and suspended sediment loss during 15 sampled storms spanning 2017‐2020. The buffer strips comprised three vegetation treatments: a deep rooting grass (Festulolium cv. Prior), a short rotation coppice willow and native broadleaved woodland trees. Over the duration of the monitoring period, reductions in total runoff, compared with the experimental control, were in the order: willow buffer strips (49%); deciduous woodland buffer strips (46%); grass buffer strips (33%). The corresponding reductions in suspended sediment loss, relative to the experimental control, were ordered: willow buffer strips (44%) > deciduous woodland buffer strips (30%) > grass buffer strips (29%). Given the three‐year duration of our new dataset, our results should be seen as providing evidence on the impacts during the establishment phase of the of the treatments. This article is protected by copyright. All rights reserved.
... Functional VFS are able to stop runoff and erosion before they reach a water body, thus keeping PP and DP within VFS boundaries where they can be incorporated in the soil matrix or solution, transformed and cycled, and taken up by the vegetation. Infiltration capacity and contact time can be optimised by selectively choosing plants with desirable characteristics, such as deep roots, stiff-stems, or tall vegetation forms-traits that have been shown to increase infiltration, slow down runoff, or support sediment deposition (Blanco-Canqui et al., 2004, Blanco-Canqui et al., 2006Wu et al., 2016). Improved infiltration increases the volume of soil that comes into contact with runoff water and takes part in P retention and cycling. ...
... If these concentrations always occur at similar positions (e.g., thalweg), the VFS could be planned accordingly, e.g., wider at areas with concentrated flow and smaller at areas that receive little runoff. Additionally, the vegetation could be adjusted; stiff grasses can slow down runoff velocities and promote a more evenly distributed flow through the VFS (grass barriers; Blanco-Canqui et al., 2004). Also, improper maintenance and vegetation aging have an effect on VFS efficacy under concentrated flow (Lambrechts et al., 2014). ...
Vegetative filter strips (VFS) are best management practices with the primary aim of protecting surface waters from eutrophication resulting from excess nutrient inputs from agricultural sources. However, we argue that there is a substantial time and knowledge lag from the science underpinning VFS to policy and implementation. Focussing on phosphorus (P), we strive to introduce a holistic view on VFS that accounts for the whole functional soil volume, temporal and seasonal effects, the geospatial context, the climatic and physico-chemical basic conditions, and the intricate bio-geochemical processes that govern nutrient retention, transformation, and transport. Specifically, we suggest a step-wise approach to custom VFS designs that links and matches the incoming P from event to multi-annual timescales from the short- and mid-term processes of P retention in the effective soil volume and to the longer-term P retention and offtake coupled to the soil-vegetation system. An a priori assessment of the P export potential should be followed by bespoke VFS designs, in line with local conditions and socio-economic and ecological constraints. To cope with increasingly nutrient saturated or functionally insufficient VFS installed over the last decades, concepts and management strategies need to encompass the transition in understanding of VFS as simple nutrient containers to multifunctional buffer zones that have a complex inner life. We need to address these associated emerging challenges and integrate their implications more thoroughly into VFS research, monitoring, policy, and implementation than ever before. Only then we may get VFS that are effective, sustainable, and persistent.
... McGregor et al. [8] reported that no-till soils under cotton lose 5.2 Mg/ha of sediment without switchgrass buffers, whereas only 2.2 Mg/ha is lost with switchgrass buffers. Furthermore, 91% of sediment was trapped with narrow switchgrass hedges [9,10]. WSG's have become a promising biofuel crop with many environmental benefits, including the displacement of fossil fuels, reduction in net CO2 emissions through soil organic carbon (SOC) sequestration, and improvements in soil and water quality [11]. ...
This research presents a novel optimization modeling framework for the existing Soil and Water Assessment Tool (SWAT), which can be used to optimize perennial feedstock production. This novel multi-objective evolutionary algorithm (MOEA) uses SWAT outputs to determine optimal spatial placement of variant cropping systems, considering environmental impacts from land-cover change and management practices. The final solution to the multi-objective problem is presented as a set of Pareto optimal solutions, where one is suggested considering the proximity to the ideal vector [1,0,0,0]. This unique approach provides a well-suited method to assist researchers and stakeholders in understanding the environmental impacts when cultivating biofuel feedstocks. The application of the proposed MOEA is illustrated by analyzing SWAT's example data set for Lake Fork Watershed. Nine land-cover scenarios were evaluated in SWAT to determine their optimal spatial placement considering maximizing biomass production while minimizing sediment yield, organic nitrogen yield, and organic phosphorous yield.
... Buffer strips, also referred to as buffer zones, riparian buffers, filter strips, and grassed waterways, are well-established agricultural practices that effectively trap sediment in the field and reduce the nonpoint source pollutants from agricultural production (Dosskey 2001;Hebblethwaite and Somody 2008;Stutter et al. 2012;USDA NRCS n.d.). The use of perennial grasses or trees as buffer strips between agricultural fields and water bodies can effectively intercept water flow and reduce soil sediments, nutrients, and chemicals from runoff (Castelle et al. 1994;Blanco-Canqui et al. 2004;Dabney et al. 2006). Previous studies have shown that buffer strips' sediment trapping efficiencies vary between 41% and 100% (Helmers et al. 2008;Liu et al. 2008), and NO 3 reduction efficiencies between 25% and 100% (Daniels and Gilliam 1996;Simpkins et al. 2002). ...
... Rainfall simulators have been effectively used to conduct most soil erosion studies (Blanco-Canqui et al., 2004a;Xiao et al., 2011;Cao et al., 2015). Although the simulator can effectively shorten the experimental period, the response of soil hydraulic properties to natural rainfall drops remains hard to determine exactly. ...
... In spring, the sediment yield of native grass barrier treatment was significantly higher than those of the two other treatments (P < 0.05), while the alfalfa barrier treatment had the lowest yield, which was different than those for runoff for all treatments (Table 3). It was mainly due to the difference in the interception mechanisms of the grass barrier for runoff and sediment (Ghadiri et al., 2001;Blanco-Canqui et al., 2004a). In all likelihood, the grass barriers mitigated runoff by lowering water velocity and then increasing infiltration, while the sediment reduction was mainly through sedimentation and vegetation interception (Hussein et al., 2007;Yuan et al., 2009). ...
... TN removal rate of the alfalfa barrier was almost 5 times that of the native grass barrier in spring and autumn. Grass barriers were mainly used to remove TN by reducing runoff and intercepting sediments (Blanco-Canqui et al., 2004a), so the alfalfa barrier had a better performance with high plant cover and stem stiffness for the smaller slope in summer. The TP removal efficiency was marginally affected by seasons and slope gradients. ...
Agricultural diffuse pollution caused by runoff and soil loss from cropland has been a serious environmental problem in the black soil area of Northeast China. While water and soil conservation measures have led to a sharp decrease in overland flow within source water sub-watersheds, they have, on the other end, affected the water security of agricultural and domestic use as the water storage capacity of downstream reservoirs decreases year by year. For this study, grass barriers, which are generally considered to have high sediment reduction efficiency, were evaluated for their efficiency as a mitigation measure of diffuse pollution within source water areas. Standard field plots were used to monitor two groups of grass barriers, alfalfa (Medicago sativaL.) and native grass (dominated by Setaria viridis(L.)Beauv.), and slope gradients (3° and 5°) under natural rainfall events over the 2012–2015 period. The results indicated that, during the maize (Zea maysL.) growing season, runoff and sediment reduction efficiencies for the alfalfa barrier were 37.91 % and 62.30 %, respectively. And more than 50 % of the nutrient loads (e.g., total nitrogen (TN), total phosphorus (TP), and nitrate (NO3⁻-N)) could be removed by the alfalfa barrier. The environmental loads mitigation efficiency of grass barrier in spring was relatively low and unstable. Both slope and barrier width had a significant impact on the water and soil conservation function of grass barriers, while rainfall intensity and grass type were mainly related to runoff reduction. Overall, these finding could provide some specific recommendations for future grass barrier design and large-scale application in a source water area of Northeast China.
... SWAT (Arnold, Srinivasan, Muttiah, & Williams, 1998) is widely used to predict discharge, water quality, and crop yield in a watershed as a function of climate, topography, soils, and management practices (Arnold et al., 1998;Neitsch, Arnold, Kiniry, & Williams, 2011 [1999][2000][2001][2002][2003][2004][2005][2006][2007][2008][2009][2010][2011][2012][2013][2014][2015] provided surface runoff, subsurface flow, and nutrient (N and P) and sediment loads from upslope, adjacent agricultural fields into the riparian zones. The simulation period of 16 yr was set up to capture four cycles of 4-yr crop rotations. ...
... SWAT (Arnold, Srinivasan, Muttiah, & Williams, 1998) is widely used to predict discharge, water quality, and crop yield in a watershed as a function of climate, topography, soils, and management practices (Arnold et al., 1998;Neitsch, Arnold, Kiniry, & Williams, 2011 [1999][2000][2001][2002][2003][2004][2005][2006][2007][2008][2009][2010][2011][2012][2013][2014][2015] provided surface runoff, subsurface flow, and nutrient (N and P) and sediment loads from upslope, adjacent agricultural fields into the riparian zones. The simulation period of 16 yr was set up to capture four cycles of 4-yr crop rotations. ...
... Although it is known that concentrated flowpaths are a major factor that increases sediment and nutrients loss from crop fields and decreases buffer effectiveness in nutrients and sediment reduction (Blanco-Canqui, Gantzer, Anderson, & Alberts, 2004;Pankau, Schoonover, Williard, & Edwards, 2012), they were not considered in this study. Wallace et al. (2018) concluded that the presence of concentrated flowpaths reduces the effectiveness of forested buffers by 54% in the study watershed. ...
Although many agricultural watersheds rely heavily on riparian buffer adoption to meet water quality goals, design and management constraints in current policies create adoption barriers. Based on focus group feedback, we developed a flexible buffer design paradigm that varies buffer width, vegetation, and harvesting. Sixteen years of daily‐scale nutrient and sediment loads simulated with the Soil and Water Assessment Tool (SWAT) were coupled to the three‐zone Riparian Ecosystem Management Model (REMM) to compare the effectiveness of traditional, policy‐based buffer designs with designs that are more flexible and integrate features important to local farmers. Buffer designs included (i) 10 m grass, (ii) 15 m grass, (iii) 15 m deciduous trees, (iv) 30 m grass and trees, (v) 30 m grass and trees with trees harvested every 3 yr, and (vi) 30 m grass and trees with grass harvested every year. Allowing harvesting in one zone of the buffer vegetation (either trees or grasses) minimally affected water quality, with annual average percent reductions differing by <5% (p > .05; 76–78% for total nitrogen [TN], 51–55% for total phosphorus [TP], and 68% for sediment). Under the highest input loading conditions, buffers with lower removal efficiencies removed more total mass than did buffers with high removal efficiencies. Thus, by focusing on mass reduction in addition to percent reduction, watershed‐wide buffer implementation may be better targeted to TN, TP, and sediment reduced. These findings have important implications for informing flexible buffer design policies and enhanced placement of buffers in watersheds impaired by nutrient and sediment.
... La eficacia de las barreras vegetales basadas en herbáceas puede ser muy alta, sobre todo si se trata de herbáceas con un cierto grado de rigidez. En un experimento con lluvia artificial (Blanco-Canqui et al. 2004) en un campo con un 5 % de pendiente la barrera con hierbas rígidas consiguió reducir un 90 % la pérdida de sedimentos mientras que con otro tipo de hierbas se redujo al 70 %. Más importante respecto al uso de hierbas con cierto grado de rigidez es que resultaron especialmente eficaces atrapando nutrientes: 5 veces más de nitrógeno orgánico, 2 veces más de amonio y 4 veces más fósforo. ...
... Buffers, including tall and erect plant hedgerows, typically feature a width of < 1 m and can effectively reduce fluxes because of the settling of sediments. Narrow hedges comprising Vetiveria zizanioides and Panicum virgatum reduced pollutant loads mainly by the settling of particulate-sorbed nutrients for instance N and P due to their dense upright growth pattern with strong rooting systems; thus, such hedges withstand high flow depths up to 600 mm (Blanco-Canqui et al. 2004). They usually show an improved performance in trapping sediment (Meyer et al. 1994) compared with Miscanthus sinensis and Festuca arundinacea because of their strong, erect leaves or culms. ...
Eutrophication has been a critical environmental issue due to soil nitrogen (N) and phosphorus (P) loss in runoff from agricultural lands. Plant hedgerow is an important measure to prevent soil erosion and reduce agricultural non-point source pollution (NPSP). In the present study, we searched 3683 research papers on plant hedgerows published from 1980 to March 2020. After screening, we used 53 effective papers on plant hedgerows for the meta-analysis by using Stata 15.1. The results showed that plant hedgerows significantly increased soil organic matter (SOM) (standardized mean difference (SMD) = 1.46; 95% confidence interval (CI) = 1.12–1.80 > 0), total N (TN) (SMD = 1.33; 95% CI 0.98–1.68 > 0), total P (SMD = 0.73; 95% CI 0.26–1.20 > 0), alkali N (SMD = 0.86; 95% CI 0.52–1.21 > 0), available P (SMD = 1.28; 95% CI 0.75–1.81 > 0) and readily available potassium (K) (SMD = 1.20; 95% CI 0.75–1.65 > 0) concentrations but exhibited no significant effects on soil total K concentration (SMD = 0.17; 95% CI − 0.13–0.47 < 0). Plant hedgerows showed a greater effect on SOM increase than soil N, P, and K, and soil TN increase than the available state, but the opposite trend was observed for P and K. This meta-analysis can clarify the influence of plant hedgerows on soil nutrients and provide ideas for the prevention and control of agricultural NPSP.
... However, few studies have quantified or compared the impact of the different types of erosion barriers (Robichaud et al., 2008a) and most of these were carried out in the USA (Robichaud, 2009;Wohlgemuth et al., 2001), and in the Mediterranean Basin, for instance in Spain (Fernández et al., 2011;Badía et al., 2015;Fernández and Vega, 2016) or in Greece (Raftoyannis and Spanos, 2005;Myronidis et al., 2010). In these works, log barriers were presented as an alternative way of reducing soil losses on fire-affected land when applied in combination with other strategies such as grass barriers (Blanco-Canqui et al., 2004), vegetative barriers (Dass et al., 2011) or contour-felled logs (Robichaud, 2000a(Robichaud, , 2000bKimiti et al., 2017). Nevertheless, there is an urgent need to evaluate and compare the effectiveness of mitigation measures against soil erosion derived from forest fires and proper restoration strategies (Santi et al., 2008;Rulli et al., 2013), as well as to propose new procedures and infrastructures adapted to the environmental and economic constraints of the field, whose impact on the water and sediment balance can be predicted (Moench and Fusaro, 2002;Robichaud, 2005Robichaud, , 2009Robichaud et al., 2007Robichaud et al., , 2013aRobichaud et al., , 2013bCerdà and Robichaud, 2009;Fernández et al., 2011). ...
Soil erosion is enhanced by wildfire, mainly due to the loss of vegetation cover and changes in soil properties. After wildfires, there is a need to control the non-sustainable soil and water losses. Of the strategies commonly applied, the use of contour felled log debris barriers to sediment trapping is widespread, but this is not always successful in Mediterranean Ecosystems. This paper evaluates the effectiveness of a new barrier which can be applied on steep terrains affected by wildfires. The hydrological response and sediment delivery were measured to test a innovative design, which are easy to transport and use. The Easy-Barriers (EB) size is 0.8 × 0.1 × 0.2 m and were designed to restore degraded areas which need a quick, low-cost solution, such as after a wildfire. The experimental design was based on the analysis of a simulated runoff flow of 0.6 l·s⁻¹ circulated on 6 plots of 24 m² (0.8 × 30 m), on each of which 2 treatments were systematically applied: Control and EB. The EB were set up after the assessment of the runoff generation and the site rainfall characteristics for “extraordinary” events. We measured the rills, the sediments collected on each slope and the topographical changes. The total load and runoff in the outlet of the plots were also quantified using sediment volume and concentration measurements. The EB resulted in a decrease in the peak flow and a delay in the runoff time at the outlet. The sediment trapping rate of the barriers was 42.7%. The soil moisture was higher in the EB plots due to the accumulated sediment. In addition to these features, the EB allow us to save between 30 and 40% of total restoration costs in comparison with traditional barriers, due to the reduction in labour costs. Moreover, all its components are biodegradable.
