Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/4/2005
Publication Date: 1/4/2005
Citation: Price, A.J., Balkcom, K.S., Arriaga, F.J. 2005. Rye biomass amount affects weed suppression levels in conservation-tillage cotton. In: Richter, D.F., editor. Proceedings of the 2005 National Cotton Council Beltwide Cotton Conference, January 4-7, 2005, New Orleans, Louisiana. p.2921-2923.
Technical Abstract: Historically, cover crop planting and termination has occurred at the discretion of growers' schedules and weather conditions. Previous research has shown that a winter cover's planting date and termination date influences both quality and quantity of residue production, and subsequent weed suppression. Therefore, a field study was conducted at two locations to determine optimum dates for planting and terminating winter cover crops to maximize biomass production, summer annual weed suppression, and cash crop yields. Rye (Secale cereale L.) was established with a no-till drill as winter cover preceding conservation-tillage cotton (Gossypium hirsutum L.) at 2 and 4 wk prior to, 2 and 4 wk after, and on the historical average first frost. In the spring, rye was terminated at 4, 3, 2, and 1 wk prior to cotton planting with glyphosate at 1 qt/ac. The rye was additionally flattened with a mechanical roller-crimper to form a dense residue mat on the soil surface. No herbicide was applied after cover termination until the 4-leaf growth stage in cotton. At E.V. Smith, rye planted 4 wk after first frost and terminated 4 wk before cotton planting produced the least biomass, 318 kg/ha, 27 times less than highest biomass treatment in which rye was planted 4 wk prior to first frost and terminated 1 wk prior to cotton planting. Correspondingly, weed biomass was 1,198 kg/ha in the treatment with the least rye biomass, 42 times greater compared to the treatment with the greatest rye biomass (Figure 1). A similar relationship was observed at the Tennessee Valley location. Cotton yield was not influenced by rye biomass (Figure 2). A similar relationship was again observed at the Tennessee Valley location.