TITLE:
Reducing Nitrogen Loss in Subsurface Tile Drainage Water with Managed Drainage and Polymer-Coated Urea in a River Bottom Soil
AUTHORS:
Patrick R. Nash, Kelly A. Nelson, Peter P. Motavalli
KEYWORDS:
Free Drainage, Managed Drainage, Nitrate, Nitrogen, Polymer-Coated Urea, Subsurface Tile Drainage
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.6 No.11,
August
20,
2014
ABSTRACT: Poorly-drained,
river bottom soils can be high corn (Zea
mays L.) yielding environments, but saturated soil conditions often reduce
corn yields. Wabash soils located in river bottoms in Northeast Missouri have
not been traditionally tile drained due to high clay content which requires
narrow tile drain spacings. Increased land prices in the region have increased
interest in tile draining poorly-drained bottom land soils to increase corn
yields which could have a deleterious effect on water quality. The objectives
of the three-year study were to determine whether use of managed subsurface
drainage (MD) in combination with a controlled release N fertilizer could
reduce the annual amount of NO3--N loss through tile
drainage water compared to free subsurface drainage (FD) with a non-coated urea
application. Annual NO3--N loss through tile
drainage water with FD ranged from 28.3 to 90.1 kg·N·ha-1. Nitrogen
fertilizer source did not affect NO3--N loss through tile
drainage water, which was likely due to limited corn uptake over the three-year
study due to adverse weather conditions. Averaged over three years, MD reduced
tile water drained 52% and NO3--N loss 29% compared to FD.
Reduction in NO3--N loss through tile
drainage water with MD compared to FD was due to reduced tile flow during the
non-cropping period. Annual flow-weighted mean concentration of NO3--N in the tile water was
5.8 mg·N·L-1 with FD and 8.1 mg·N·L-1 with MD. Tile
draining river bottom soils at this location for continuous corn production may
not pose a health risk over the evaluated duration.