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Nitrogen Response in Cotton as Affected by Tillage System and Irrigation Level
Author(s) -
Bronson K. F.,
Onken A. B.,
Keeling J. W.,
Booker J. D.,
Torbert H. A.
Publication year - 2001
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2001.6541153x
Subject(s) - lint , loam , tillage , agronomy , irrigation , fertilizer , evapotranspiration , environmental science , mathematics , soil water , biology , soil science , ecology
More than 0.5 million ha of irrigated cotton ( Gossypium hirsutum L.) are grown in the Southern High Plains of Texas. Conservation tillage cotton in terminated wheat ( Triticum aestivum L.) has been shown to improve water use efficiency and reduce wind erosion. However, limited N fertilizer response research has been done in this system. The objective of this 3‐yr field study at Lubbock, TX was to characterize the response to N fertilizer (0, 28, 56, 84, or 112 kg N ha −1 ) at varying irrigation levels [0, 25, 50, or 75 % Evapotranspiration (ET) replacement] for conventional and conservation tillage cotton in an Acuff loam (fine loamy, mixed, superactive, thermic, Aridic Paleustoll). Additionally, we tested the chlorophyll meter as an indicator of in‐season N status of cotton and compared it to petiole NO 3 –N analysis. Cotton lint yields showed a quadratic response to irrigation level in 1996 and 1997, and a linear response in the drought year of 1998. Maximum lint yield varied from 71 to 97 % ET replacement. In 1997 and 1998, cotton lint yields responded to N at the 50 and 75% estimated ET replacement irrigation levels, but not at the 0 or 25% ET levels. Quadratic‐plateau models indicated that 19 to 38 kg N additional fertilizer ha −1 was needed to produce economically optimum lint yields near 1100 kg N ha −1 with conservation tillage than with conventional tillage. Chlorophyll meter and petiole NO 3 –N readings were positively related to N rate but were not affected by tillage system.