HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Reiter, M. S. Articles by Burmester, C. H. PubMed Articles by Reiter, M. S. Articles by Burmester, C. H. Agricola Articles by Reiter, M. S. Articles by Burmester, C. H. Related Collections Cover Crops Cotton Nitrogen

SOIL FERTILITY & PLANT NUTRITION

Cotton Nitrogen Management in a High-Residue Conservation System: Source, Rate, Method, and Timing

^a Virginia Polytechnic Inst. and State Univ., Eastern Shore Agric. Research and Ext. Center, 33446 Research Dr., Painter, VA 23420
^b USDA-ARS, J. Phil Campbell Sr. Natural Resource Conserv. Center, 1420 Experiment Station Rd., Watkinsville, GA 30677
^c Auburn Univ., Agronomy and Soils Dep., 202 Funchess Hall, Auburn University, AL 36849

^* Corresponding author (mreiter{at}vt.edu).

More than 70% of cotton (Gossypium hirsutum L.) grown in the Tennessee Valley of northern Alabama is produced using conservation tillage systems with cereal cover crops. The resulting decreased N efficiency requires development of new N fertilizer recommendations. We conducted a replicated 3-yr field study on a Decatur silt loam (fine, kaolinitic, thermic Rhodic Paleudult) to determine the effects of N source (NHNO₃ [AN] and urea–NH₄NO₃ [320 g N kg^–1, UAN]), N rates (0, 45, 90, 135, and 180 kg N ha^–1), N application timing (all at-planting or 50:50 split between planting and first match head square), and N application method (banded or broadcast) on cotton grown in high-residue rye (Secale cereale L.) conservation systems. Generally, 67 to 80% more N was needed than average conventional N rate recommendations to reach optimal yields if N was split applied, while N applied at-planting had yield responses with 169% of the recommended N rate. Urea–NH₄NO₃ applications resulted in greater yields when banded at-planting (1045 kg lint ha^–1), while AN was more effective when broadcast applied at-planting or in split applications (1002 and 996 kg lint ha^–1, respectively). Chlorophyll meter readings, petiole NO₃, and leaf N were not useful predictors of cotton N deficiency or yield. The most efficient practice is to apply 88% more N (126 kg N ha^–1 total) than the mean conventional N cotton recommendation as a broadcast split application using AN. We speculate that N requirements may be decreased with time as C and N pools reach a new equilibrium.

Abbreviations: AN, ammonium nitrate • HVI, high-volume instrumentation • UAN, urea–ammonium nitrate