Weed science and management, in soil sciences, land cover, and land use

Authors: KELTON, JESSICA - AUBURN UNIVERSITY; Price, Andrew

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 3/9/2009
Publication Date: 9/1/2009
Citation: Kelton, J.A., Price, A.J. 2009. Weed science and management, in soil sciences, land cover, and land use. In: Verheye, W.H., editor. Soils, Plant Growth and Crop Production, in Encyclopedia of Life Support Systems (EOLSS), Developed under the Auspices of the UNESCO, Eolss Publishers, Oxford ,UK.

Interpretive Summary: An integral component of conservation agriculture systems in cotton is the use of a high-residue winter cover crop; however, terminating such cover crops is a cost and planting into high-residue is a challenge. Black oat, rye, and wheat winter cover crops were flattened with a straight-blade mechanical roller-crimper alone or followed by four reduced rates of glyphosate. Results showed that rolling followed by glyphosate applied at rates less than half the standard use can effectively and reliably terminate mature cereal winter cover crops; thus maintaining cotton population and protecting growth. Additionally, reduced glyphosate rates as low as three-quarters of the standard use rate alone can effectively terminate immature cereal covers. Rolling mature winter cereal cover crops will likely conserve more soil moisture compared to standing covers; however, rolling immature cereal cover crops provides no benefit.

Technical Abstract: An integral component of conservation agriculture systems in cotton is the use of a high-residue winter cover crop; however, terminating such cover crops is a cost and planting into high-residue is a challenge. Black oat, rye, and wheat winter cover crops were flattened with a straight-blade mechanical roller-crimper alone or followed by four rates of glyphosate. At 3 weeks after treatment at all locations, averaged across winter cover crops, rolling plus glyphosate at 0.42 kg ae/ha or greater terminated the covers = 96%. In 2004, cotton seed lint yield following rolled rye was higher than yield following non-rolled rye. In 2005, rolling rye excluding glyphosate or reduced rates of glyphosate decreased yield, likely due to rye immaturity at time of rolling. In 2006, cotton seed lint yield following rolled rye was similar to yield following a non-rolled rye winter cover crop. At Robertsdale in 2005, yield was highest following non-treated and non-rolled treatments. Rolling alone decreased yield by over 700 kg/ha. Increasing glyphosate rate in either rolled or non-rolled wheat decreased lint yield. At Tennessee Valley in 2005, rolling alone increased yield compared to non-treated plots. No increase in yield was observed by increasing glyphosate rates over rolling alone, reflecting adequate termination by the rolling treatment. Results showed that rolling followed by reduced glyphosate rates as low as 0.42 kg ae/ha can effectively and reliably terminate mature cereal winter cover crops; thus maintaining cotton population and protecting growth. Additionally, reduced glyphosate applied as low as 0.84 kg ae/ha alone can effectively terminate immature cereal covers. Rolling mature winter cereal cover crops will likely conserve more soil moisture compared to standing covers; however, rolling immature cereal cover crops provides no benefit.