Premium
Distribution of Residual Nitrate‐Nitrogen in Long‐Term Fertilization Studies of an Alfisol Cropped to Cotton
Author(s) -
McConnell J. S.,
Baker W. H.,
Frizzell B. S.
Publication year - 1996
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/jeq1996.00472425002500060032x
Subject(s) - agronomy , irrigation , loam , alfisol , soil water , environmental science , fertilizer , human fertilization , soil horizon , biology , soil science
Nitrogen fertilizer use in cotton ( Gossypium hirsutum L.) production has recently come under scrutiny as a potential source of NO − 3 contamination of streams and groundwater. This study was conducted to evaluate the distribution of NO − 3 ‐N in soil cropped to continuous cotton and determine the fertilization and irrigation conditions that might exacerbate the accumulation of NO − 3 ‐N. Long‐term N fertilization studies were conducted in five side‐by‐side irrigation blocks at the Southeast Branch Experiment Station at Rohwer, AR, on an Hebert silt loam (fine‐silty, mixed, thermic Aeric Ochraqualf) soil. Soil samples were taken in the early spring (1994) to a depth of 1.5 m in 15‐cm increments from three replicates of each N‐treatment from four irrigated and one dryland block and analyzed for NO − 3 ‐N. Soil cropped to dryland cotton showed excessive accumulation (up to 101.2 mg NO − 3 ‐N kg −1 ) of NO − 3 ‐N when treated with N rates of 67 kg N ha −1 and greater. Soils cropped to irrigated cotton did not accumulate as much NO − 3 ‐N as dryland cotton. Soil NO − 3 ‐N was unaffected by N treatments at any depth in two of three center pivot irrigated blocks. Slight increases in soil NO − 3 ‐N were observed under furrow‐irrigated conditions with the greatest N treatments (134 and 168 kg N ha −1 ). Dryland cotton was more likely to have accumulations of NO − 3 ‐N in the soil profile than irrigated cotton. This was probably due to reduced plant uptake of fertilizer N under nonirrigated production conditions.