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Submitted to: Hungarian Agricultural Engineering
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 10/19/2013 Publication Date: 12/14/2013 Publication URL: https://handle.nal.usda.gov/10113/5454534 Citation: Kornecki, T.S., Price, A.J., Balkcom, K.S. 2013. Effects of terminating cover crops with rolling/crimping and herbicides in a cotton no-till system. Hungarian Agricultural Engineering. 25:59-63. Interpretive Summary: Cover crops are an essential component of no-till agriculture because of important benefits such as improved soil quality, weed control and moisture conservation. Typically, three weeks after rolling are required to achieve cover crop termination rates above 90%, and to eliminate competition between the cover crop and cash crop for soil moisture. A common method to speed-up the cover crop termination and keep recommended cash crop planting dates is to apply herbicides in addition to rolling. In organic production, synthetic herbicides cannot be used. An experiment was conducted in 2009 and 2010 in central Alabama to study the effectiveness of terminating cereal rye and crimson clover using an experimental roller, glyphosate and two organic herbicides. Results indicate that rye termination rates three weeks after the rolling were above 95% for rolling and herbicides. In both years applying glyphosate with rolling helped to increase rye termination near 100% two weeks after rolling. In contrast, applying organic herbicides did not increase the termination process compared with the roller/crimper alone. The termination process can be faster with continuous or reduced supplemental applications of glyphosate compared to the roller alone, but not with organic herbicides. Rolling and herbicides did not influence cotton population. Cotton yield following rye was higher and produced more bolls compared to crimson clover. This difference could be attributed to nitrogen released by crimson clover that promoted vegetative growth and limited reproductive development. Cotton plants following crimson clover were also taller compared to rye. Overall, rolling and herbicides did not affect cotton population and yield. In contrast, cotton population and yield were affected by different weather conditions during growing seasons of 2009 and 2010. Technical Abstract: In fall of 2008, a field experiment was initiated in central Alabama to study the effects of rolling/crimping and different herbicides with different application rates on cover crops termination rates, cotton population and yield. Results from 2009 and 2010 growing seasons are presented. A roller/crimper only and with supplemental use of two organic herbicides (Weed-Zap and vinegar 20% acidity) and glyphosate were applied as a continuous spray, every other crimp and every third crimp controlled by a high speed solenoid valve nozzle system to terminate cereal rye and crimson clover. In 2009, three weeks after rolling, termination rates due to rolling/crimping and herbicide treatments for cereal rye were between 96-100%, whereas for crimson clover were lower (75.3–82.4%) because of moisture excess. Three weeks after rolling, in 2010, termination rates for cereal rye were 96.4 to100%, and between 93.1 to 100% for crimson clover. In 2009, rolling treatments and cover crop type had no effect on cotton population which averaged 45,830 plants ha-1. Contrary, in 2010 cotton population due to rye was lower: 27291 plants ha-1 compared to 47411 plants ha-1 due to clover. In 2009, significantly higher average seed cotton yield was 3494 kg ha-1 for cereal rye compared to 2853 kg ha-1 for crimson clover. In 2010 cotton yield was affected by very dry and hot summer. Average yield for rye was 1793 kg ha-1, whereas for crimson clover the seed cotton yield was 1638 kg ha-1. Lower cotton yield with crimson clover was associated with a higher vegetative plant growth due to Nitrogen release from crimson clover residue. |
