Insights on agricultural nitrate leaching from soil block mesocosms.

Quantifying nitrate leaching in agricultural fields is often complicated by inability to capture all water draining through a specific area. We designed and tested undisturbed soil monoliths (termed "soil block mesocosms") to achieve complete collection of drainage. Each mesocosm measures 1.

A review of ecosystem services from edge-of-field practices in tile-drained agricultural systems in the United States Corn Belt Region.

Edge-of-field management practices that reduce nutrient pollution from tile drainage while contributing habitat and other ecosystem services are needed to enhance agricultural systems in the US Corn Belt Region. In this review, we identified edge-of-field and catchment scale agricultural conservation practices for intercepting and treating tile drainage. The reviewed conservation practices were (1) controlled drainage, also known as drainage water management (USDA-NRCS Code 554); (2) drainage water recycling (USDA-NRCS Code 447); (3) denitrifying bioreactors (USDA-NRCS Code 605); (4) saturated buffers (USDA-NRCS Code 604); and (5) constructed or restored wetlands designed for water quality improvement (USDA-NRCS Code 656) herein referred to as water quality wetlands.

Improving model capability in simulating spatiotemporal variations and flow contributions of nitrate export in tile-drained catchments.

It is essential to identify the dominant flow paths, hot spots and hot periods of hydrological nitrate-nitrogen (NO-N) losses for developing nitrogen loads reduction strategies in agricultural watersheds. Coupled biogeochemical transformations and hydrological connectivity regulate the spatiotemporal dynamics of water and NO-N export along surface and subsurface flows. However, modeling performance is usually limited by the oversimplification of natural and human-managed processes and insufficient representation of spatiotemporally varied hydrological and biogeochemical cycles in agricultural watersheds.

Poorly drained depressions can be hotspots of nutrient leaching from agricultural soils.

Much of the US Corn Belt has been drained with subsurface tile to improve crop production, yet poorly drained depressions often still flood intermittently, suppressing crop growth. Impacts of depressions on field-scale nutrient leaching are unclear. Poor drainage might promote denitrification and physicochemical retention of phosphorus (P), but ample availability of water and nutrients might exacerbate nutrient leaching from cropped depressions.

Potential of water quality wetlands to mitigate habitat losses from agricultural drainage modernization.

Given widespread biodiversity declines, a growing global human population, and demands to improve water quality, there is an immediate need to explore land management solutions that support multiple ecosystem services. Agricultural water quality wetlands designed to provide both water quality benefits and wetland and grassland habitat are an emerging restoration solution that may reverse habitat declines in intensive agricultural areas. Installation of water quality wetlands in the Upper Midwest, USA, when considered alongside the repair and modification of aging agricultural tile drainage infrastructure, is a likely scenario that may mitigate nutrient pollution exported from agricultural systems and improve crop yields.

Water quality performance of wetlands receiving nonpoint-source nitrogen loads: Nitrate and total nitrogen removal efficiency and controlling factors.

Nonpoint-source nitrogen (N) loads in the U.S. Corn Belt are a major concern both for local impacts on receiving waters and for contributing to hypoxia in the Gulf of Mexico.