Benefits of Uniform Row Spacing in a Cotton-Corn Conservation System

Authors: Raper, Randy; Balkcom, Kipling; Arriaga, Francisco; Price, Andrew; Kornecki, Ted; Schwab, Eric

Submitted to: Cotton Research and Extension Report
Publication Type: Experiment Station
Publication Acceptance Date: 2/15/2009
Publication Date: 3/15/2009
Citation: Raper, R.L., Balkcom, K.S., Arriaga, F.J., Price, A.J., Kornecki, T.S., Schwab, E.B. 2009. Benefits of uniform row spacing in a cotton-corn conservation system. 2008 Cotton Research and Extension Report. No. 33. p. 13-15.

Interpretive Summary:

Technical Abstract: Crop rotations are an important part of every conservation system. However, different crops have varying needs and much of the data for their growth was obtained in a monoculture. When these crops are integrated into a conservation system that minimizes surface disturbance, tillage practices may need to be further examined to choose the best solutions for both crops. Soil compaction in the southeastern region of the U.S. is extremely prevalent and routinely reduces crop yields unless inrow subsoiling is annually conducted. In 2006, an experiment was initiated at the E.V. Smith Research Center in Shorter, Alabama, to evaluate the effects of crop rotation, row spacing, and tillage practices on corn and cotton production systems. Soils at the site are mostly in the Compass series and are coarse-loamy, siliceous, subactive, thermic Plinthic Paleudults. The conservation system included a cover crop system which was crimson clover (Trifolium incarnatum L.) prior to corn, and rye (Secale cereale L.) prior to cotton. A dryland corn-cotton rotation was established at the site in the spring of 2007 with corn being planted on the eastern half of the plots either in 30- or 36-inch rows and cotton being planted on the western half of the plots in 36-inch rows. In 2008, the crops were rotated with cotton being planted on 36-inch rows in the previous corn plots and corn being planted either in 30- or 36-inch rows following the cotton in 36-inch rows. Plant populations were maintained at similar levels in both row spacings with cotton being planted with 45,000 seeds per acre and corn with 28,000 seeds per acre. Additionally, four in-row subsoiling treatments were arranged within the experiment: (1) annual, (2) spring prior to corn, (3) spring prior to cotton, and (4) none. All of the plots were managed with conservation systems which used no surface tillage. Highest corn yields were found in the 36-inch rows, which differs from the commonly held belief that increased corn yields are obtained in our region with narrower row spacings of 30 inches. Corn yields were not found to suffer from in-row subsoiling conducted almost a year previously before the cotton crop. Cotton yields were found to benefi t from in-row subsoiling conducted just prior to planting. Soil strength information verifi ed that intense soil compaction was found beneath a portion of the rows in the cotton plots that had previously been under the previous corn crop’s trafficked row middles.