Abstract
Many studies have evaluated nitrate-N leaching from tile-drained agricultural soils, but little longterm research has been performed on well-drained soils commonly throughout the Midwest. Equilibrium tension lysimeters installed at a depth of 1.4 m were used to measure year-round (12 month) nitrate-N leaching below chisel-plow (CP) and no-tillage (NT) continuous corn (Zea mays L.) agroecosystems to determine the potential effects of common agricultural practices on subsurface water quality. The corn systems were fertilized at a rate of 10 kg N ha-1 of starter fertilizer and 180 kg N ha-1 as NH4NO3. For comparison, nitrate-N leaching from a natural ecosystem was performed on a nearby prairie restoration (PR). Drainage, nitrate-N leaching loss, and flow-weighted mean nitrate-N concentrations for 8 years of data (1996-2003) are reported for the CP, NT and PR ecosystems. Results show that 52%, 37%, 16% of cumulative precipitation was collected as drainage, while 18%, 19%, 0.5% of the total N input was leached as nitrate-N in the CP, NT, and PR, respectively. Nearly three-quarters of the total nitrate-N was leached from each ecosystem during the period from 1 April to 30 June. The 8-yr, flow-weighted mean nitrate-N concentration measured in leachate was 9.5, 12.2 and -1 for the CP, NT and PR treatments. Annual drainage volumes and nitrate-N leaching losses were highly variable, stressing the importance of long-term studies capable of measuring year-round drainage for understanding N leaching dynamics and evaluating effects of cropping practices on potential groundwater quality.
Highlights
One half of the United States’ drinking water comes from groundwater [1]; while in upper Midwestern states such as Wisconsin approximately 70% of residents rely on groundwater as their primary water supply [2]
In the prairie restoration (PR) system, 1998 was the year of largest drainage, 2001 was the second largest drainage, while 2000 was the third largest drainage (Table 1). This difference between the two corn treatments versus the prairie may reflect the influence of the controlled burns conducted in the spring of 1998 and 2001 which coincided with the two greatest drainage years of the PR treatment
Three-quarters of N leaching loss occurred during the 3-month period from April 1 to June 30; measuring year-round drainage is important for relating the amount of N loss below agricultural ecosystems to the potential impact on groundwater quality
Summary
One half of the United States’ drinking water comes from groundwater [1]; while in upper Midwestern states such as Wisconsin approximately 70% of residents rely on groundwater as their primary water supply [2]. The US Environmental Protection Agency has a primary drinking water standard for nitrate-N of 10 mg∙L−1. Municipal water supplies that exceed federal safe drinking water standards for nitrate-N have cost communities in Wisconsin millions of dollars when municipalities have had to install nitrate removal systems or drill deeper wells [5]. Many private well owners and small businesses in rural areas have spent hundreds to thousands of dollars to install water treatment systems or drill deeper wells to reduce nitrate concentrations from agricultural sources [6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
