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ARS Home » Midwest Area » Columbia, Missouri » Cropping Systems and Water Quality Research » Research » Publications at this Location » Publication #329661
Title: Processes affecting the transport of nitrogen in groundwater and factors related to slope position

Author
item WICKRAMARATHNE, N - University Of Missouri
item UDAWATTA, R - University Of Missouri
item Lerch, Robert
item LIU, F - University Of Missouri

Submitted to: International Soil and Water Conservation Conference
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2016
Publication Date: 7/24/2016
Citation: Wickramarathne, N., Udawatta, R.P., Lerch, R.N., Liu, F. 2016. Processes affecting the transport of nitrogen in groundwater and factors related to slope position. International Soil and Water Conservation Conference, July 24-27, 2016, Louisville, Kentucky. p. 150.

Interpretive Summary:

Technical Abstract: Nitrate (NO3-) pollution of water resources has been a major problem for years, causing contaminated water supplies, harmful effects on human health, and widespread eutrophication of fresh water resources. The main objectives of this study were to: 1) understand the processes affecting NO3- transport to groundwater beneath two land covers, grazed pasture and grazed pasture with poplar trees at the foot-slope, under livestock management; and 2) to assess the fate of NO3- as influenced by landscape position. Groundwater samples were collected weekly from piezometers at and analyzed for NO3-N and total nitrogen (TN) concentration. Average NO3-N concentrations ranged from 0.06 to 3.05 ppm, and average TN concentrations ranged from 0.44 to 3.35 ppm, with the lowest concentrations in the foot slope wells. Comparisons between land cover for the foot slope wells showed that average NO3-N concentrations were 0.007 ppm in the pasture with poplar trees and 0.08 ppm in the pasture only treatment. Average TN concentrations were 0.31 ppm in the pasture with poplar trees and 0.48 ppm in the pasture only watershed. Results also showed decreasing NO3-N concentrations with decreasing depth to the water table. The results of this experiment showed that the depositional environment and shallow water table at the footslope position creates a setting with high potential for denitrification. Given the significant NO3-N contamination at depths in excess of 10 m at the summit, these results demonstrated the ability of riparian areas to significantly reduce NO3-N contamination along the groundwater flow path from summit to footslope.