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Losses of Nitrogen in Surface Runoff in the Blackland Prairie of Texas
Author(s) -
Kissel D. E.,
Richardson C. W.,
Burnett Earl
Publication year - 1976
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/jeq1976.00472425000500030014x
Subject(s) - surface runoff , environmental science , sorghum , soil water , agronomy , fertilizer , vertisol , infiltration (hvac) , hydrology (agriculture) , nitrogen , soil science , chemistry , geology , biology , ecology , geography , geotechnical engineering , organic chemistry , meteorology
Our objective in this study was to determine NO 3 − ‐N and total N losses in surface runoff from Houston Black clay, a swelling clay soil with a relatively low infiltration rate. The study was carried out on duplicate 4‐ha watersheds cropped to a rotation of grain sorghum ( Sorghum bicolor [L.]), cotton ( Gossypium hirsutum [L.]), and oats ( Avena sativa [L.]), all fertilized at recommended rates of N application. The loss of NO 3 − ‐N varied considerably during the study, depending on events before each runoff‐producing storm. Concentrations of NO 3 − ‐N were usually highest just after fertilizer application when the soil was near field capacity and lowest when large amounts of water infiltrated into dry soil immediately before runoff. During runoff‐producing storms just after fertilizer application, the concentrations were lowest in the initial runoff and highest near the end of the runoff event. To compute NO 3 − ‐N losses with reasonable accuracy on these soils, the shape of the entire NO 3 − ‐N concentration curve needed to be well defined. In general, the results of this study indicate that a small and probably insignificant amount of N is lost to surface waters when crops are fertilized at recommended N rates in the Texas Blackland Prairie. For the entire 5‐year study, the mean concentration of NO 3 − ‐N in runoff was 2.9 and 2.3 ppm NO 3 − ‐N for the duplicate watersheds. The mean total loss of NO 3 − ‐N was 3.2 kg ha −1 year −1 . Losses of sediment associated N were about 5 kg N ha −1 year −1 .