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Nitrate, Phosphorus, and Sulfate in Subsurface Drainage Water
Author(s) -
Baker J. L.,
Campbell K. L.,
Johnson H. P.,
Hanway J. J.
Publication year - 1975
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1975.00472425000400030027x
Subject(s) - surface runoff , drainage , tile drainage , phosphorus , environmental science , hydrology (agriculture) , nitrate , subsurface flow , soil water , water quality , surface water , nutrient , soil science , groundwater , chemistry , geology , environmental engineering , ecology , geotechnical engineering , organic chemistry , biology
Measurements made over a 4‐year study of flow and NO 3 ‐N, PO 4 ‐P, total P, and SO 4 ‐S content of subsurface drainage water from tile‐drained cropland indicate that annual nutrient losses are highly variable. Annual losses of phosphorus, SO 4 ‐S, and NO 3 ‐N ranged from 0 to 0.04, 0 to 32, and 0 to 93 kg/ha, respectively, being very dependent on the amount of water lost. Because of low concentrations of phosphorus, losses with subsurface drainage water were insignificant when compared with losses associated with surface runoff. Concentrations of SO 4 ‐S and NO 3 ‐N were seemingly inversely related. Tile drainage water with consistently high NO 3 ‐N content relative to surface runoff (> 10 ppm even under the low‐fertility management of this study, 224 kg/ha of N over 5 years) is believed responsible for the high NO 3 ‐N content sometimes found in a river draining central Iowa. The nitrate content of water from the saturated and unsaturated zones of the soil profile indicates that waves or pulses of water, with different NO 3 ‐N concentrations, moving through the soil profile cause the observed variation of NO 3 ‐N content of subsurface drainage water with time and flow rate. Such variations illustrate the difficulty of identifying water‐quality trends from limited data.