Mitigating Nonpoint Source Pollution in Agriculture with Constructed and Restored Wetlands

O’Geen, A. T.; Budd, Robert; Gan, Jay; Maynard, Jonathan J.; Parikh, Sanjai J.; Dahlgren, Randy A.

doi:10.1016/s0065-2113(10)08001-6

Cited by 99 publications

(75 citation statements)

References 275 publications

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“…Afforestation and reforestation helped in sequestering the gases emitted by soils, while agricultural land expansion gradually has been increasing its total emission. However, as it has been reported, intensive agriculture, its increasing inputs (fertilizer and pesticides) and practices like enteric fermentation, irrigation and tillage and mechanization, crop residues burning, lead to emissions of N 2 O, CH 4 and CO 2 which in turn, contribute to soil, air and water quality pollution with more effects on poor countries whose adaption measures are not sufficient (Barber and Quinn, 2012;Braune and Xu, 2010;O'Geen et al, 2010). By considering how faster agriculture is expanding in Rwanda, it is possible, that under the expansion of seasonal cropland (Figure 3), the increased forest area may be undermined for crop land reasons, being associated with increasing fertilizers application and expansion of irrigated areas (Table 1), which in turn, lead to increasing agricultural emissions.…”

Section: Discusssionmentioning

confidence: 99%

Agricultural impact on environment and counter measures in Rwanda

Nahayo¹,

Li²,

Kayiranga³

et al. 2016

Afr. J. Agric. Res.

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Rapid intensive agriculture often generates serious environmental concerns including soil erosion, water pollution and greenhouses gases. This paper assesses the impact of agriculture and its practices on environment in Rwanda from 1990 to 2012. Data provided by the World Bank were analyzed with Origin Pro 9 for statistical analysis. Also, a review on physical-chemical parameters and heavy metals of water resources home to or surrounded by cultivated mountains was adopted in this study. The results showed that agricultural records decreased from 1990 to 1994. However, after then, the short season cropland like cereals increased from 7.04 to 17.45%; roots and tubers increased from 13.17 to 21.69% in 1995 and 2012, respectively, whilst permanent cropland remained constant at 10.13%. As Rwandan soil is almost steep slope, this heavily exposes the soil to erosion, fertility loss and landslides as permanent crops to enhance fertility and erosion control are decreasing. Also, fertilizers increased from 2,149 to 27,748 tons, irrigation spaced from 4,000 to 10,000 ha which can be the reasons of rise of agricultural emissions. The reviewed studies estimated high concentration of the total nitrogen, total suspended solids, manganese, lead and iron exceeding the standards of the European Union and World Health Organization. From the above findings, it is suggested to regularly monitor water quality and promote its purification measures, to fertilize and irrigate timely and appropriately, expand areas under agroforestry and permanent crops, promote bench terraces practices for durable soil erosion control and water quality in Rwanda.

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Section: Discusssionmentioning

confidence: 99%

Agricultural impact on environment and counter measures in Rwanda

Nahayo¹,

Li²,

Kayiranga³

et al. 2016

Afr. J. Agric. Res.

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“…Other studies of wetlands receiving agricultural runoff report NO 3 -N removal efficiencies ranging from 0 to as high as 99% (summarized by O'Geen et al, 2010). Comparisons of wetland-N treatment capability, however, is challenging in agricultural settings, because climate, flow characteristics (e.g., flow pulses), N species and N load vary across a wide range of temporal and spatial scales.…”

Section: Nitrate Mass Balancementioning

confidence: 99%

“…Comparisons of wetland-N treatment capability, however, is challenging in agricultural settings, because climate, flow characteristics (e.g., flow pulses), N species and N load vary across a wide range of temporal and spatial scales. Wetland characteristics (shape, size, depth, age, soil characteristics and vegetation) also vary widely (O'Geen et al, 2010).…”

Section: Nitrate Mass Balancementioning

confidence: 99%

“…Similarly, high but variable NO 3 removal rates (35-100%) have been documented from water seeping through side berms of a constructed wetland in Illinois (Larson et al, 2000). Variation in nitrate removal is a result of many factors such as hydraulic residence time, soil properties, vegetation characteristics, variability in input loads, N loading, temperature, dissolved oxygen concentration, climate and nitrogen form (nitrate, ammonium or organic) in input waters (Phipps and Crumpton, 1994;Beutel et al, 2009;O'Geen et al, 2010).…”

Section: Introductionmentioning

confidence: 96%

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Fate of nitrate in seepage from a restored wetland receiving agricultural tailwater

Brauer

Maynard

Dahlgren

et al. 2015

Ecological Engineering

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A B S T R A C TConstructed and restored wetlands are a common practice to filter agricultural runoff, which often contains high levels of pollutants, including nitrate. Seepage waters from wetlands have potential to contaminate groundwater. This study used soil and water monitoring and hydrologic and nitrogen mass balances to document the fate and transport of nitrate in seepage and surface waters from a restored flow-through wetland adjacent to the San Joaquin River, California. A 39% reduction in NO 3 -N concentration was observed between wetland surface water inflows (12.87 AE 6.43 mg L À1 ; mean AE SD) and outflows (7.87 AE 4.69 mg L À1 ). Redox potentials were consistently below the nitrate reduction threshold ($250 mV) at most sites throughout the irrigation season. In the upper 10 cm of the main flowpath, denitrification potential (DNP) for soil incubations significantly increased from 151 to 2437 mg NO 3 -N m À2 d À1 when nitrate was added, but showed no response to carbon additions indicating that denitrification was primarily limited by nitrate. Approximately 72% of the water entering the wetland became deep seepage, water that percolated beyond 1-m depth. The wetland was highly effective at removing nitrate (3866 kg NO 3 -N) with an estimated 75% NO 3 -N removal efficiency calculated from a combined water and nitrate mass balance. The mass balance results were consistent with estimates of NO 3 -N removed (5085 kg NO 3 -N) via denitrification potential. Results indicate that allowing seepage from wetlands does not necessarily pose an appreciable risk for groundwater nitrate contamination and seepage can facilitate greater nitrate removal via denitrification in soil compared to surface water transport alone.

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“…Compared to constructed wetlands, the contaminant removal processes in natural wetlands are generally more complicated to study because they have diffuse, spatially and temporally variable groundwater inflows and outflows that are difficult to access and measure. There have been few attempts to quantify the effectiveness of natural seepage wetlands [22], whereas nutrient removal of constructed wetlands with discrete inflows and outflows is comparatively well studied [3,[23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of a Natural Headwater Wetland for Reducing Agricultural Nitrogen Loads

Uuemaa

Palliser

Hughes

et al. 2018

Water

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Natural wetlands can play a key role in controlling non-point source pollution, but quantifying their capacity to reduce contaminant loads is often challenging due to diffuse and variable inflows. The nitrogen removal performance of a small natural headwater wetland in a pastoral agricultural catchment in Waikato, New Zealand was assessed over a two-year period (2011)(2012)(2013). Flow and water quality samples were collected at the wetland upper and lower locations, and piezometers sampled inside and outside the wetland. A simple dynamic model operating on an hourly time step was used to assess wetland removal performance for key N species. Hourly measurements of inflow, outflow, rainfall and Penman-Monteith evapotranspiration estimates were used to calculate dynamic water balance for the wetland. A dynamic N mass balance was calculated for each N component by coupling influent concentrations to the dynamic water balance and applying a first order areal removal coefficient (k 20 ) adjusted to the ambient temperature. Flow and water quality monitoring showed that wetland was mainly groundwater fed. The concentrations of oxidised nitrogen (NO x -N, Total Organic Nitrogen (TON) and Total-N (TN) were lower at the outlet of the wetland regardless of flow conditions or seasonality, even during winter storms. The model estimation showed that the wetland could reduce net NO x -N, NH 4 -N, TON and TN loads by 76%, 73%, 26% and 57%, respectively.

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Mitigating Nonpoint Source Pollution in Agriculture with Constructed and Restored Wetlands

Cited by 99 publications

References 275 publications

Agricultural impact on environment and counter measures in Rwanda

Agricultural impact on environment and counter measures in Rwanda

Fate of nitrate in seepage from a restored wetland receiving agricultural tailwater

Effectiveness of a Natural Headwater Wetland for Reducing Agricultural Nitrogen Loads

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