Spatial Variability of Cotton and Corn Yields Over a 6-year Period in the Mississippi Delta.
(S-ebelhar234864-oral)
Authors:
M.W. Ebelhar* - Miss State Univ.
D.R. Clark - Miss State Univ.
Abstract:
Mississippi producers are continually exposed to new technologies for day-to-day operations of the modern farm. Site specific management takes advantage of
computer technology and is being evaluated all through the Cotton Belt. Global Positioning Systems (GPS) make it possible to geo-reference specific areas of fields and, along with Geographic Information Systems (GIS), become the framework for multi-layered data that can be used to describe spatial variability in fields. Six years of data has been collected from a 6-ha field on the Delta Research and Extension Center. Corn was grown in 1998, 2000, and 2002 while rotating to cotton in 1999, 2001, and 2003. The 496-plot (cell, 4-row plot on 102-cm spacing, 25m in length) field was geo-referenced with plots maintained in the same area throughout the study. Corn and cotton yields were determined by harvesting with commercial equipment adapted for plot harvesting. At the end of each growing season, soil samples were taken from each individual cell and analyzed for available nutrients and other soil characteristics. The yield data was summarized and the yields from each individual year also converted to relative yield for that year. Individual corn yields ranged from 8.30 to 11.65, 9.53 to 13.16, and 9.04 to 14.43 Mg ha-1 for corn years, respectively. The average grain yield across all cells were 9.78, 11.39, and 12.68 Mg ha-1. Cotton lint yields ranged from 1063 to 1689 kg ha-1 in 1999, 354 to 1372 kg ha-1 in 2001, and 1252 to 2054 kg ha-1 in 2003. While relative corn yields were fairly consistent, relative lint yields were quite different depending on the year. In 2001, relative lint yields ranged from 25.8% to 100.0% with the average relative yield at 74.5% compared to >80% average relative yield in the other two years. Generally, yields maps were different from crop to crop as well as year to year. Multiple yield maps will be vital to site-specific management.
Speaker Information: M. Wayne Ebelhar, Miss State Univ., Delta Research and
Extension Center P. O. Box 197, Stoneville, MS 38776; Phone: (662) 686-3247; E-mail: