Effects of rolling operations on cover crops termination, soil moisture, and soil strength in a southeastern US no-till system

Authors: Kornecki, Ted; Price, Andrew; Arriaga, Francisco; Raper, Randy

Submitted to: World Congress of Soil Science
Publication Type: Proceedings
Publication Acceptance Date: 8/1/2010
Publication Date: 8/1/2010
Citation: Kornecki, T.S., Price, A.J., Arriaga, F.J., Raper, R.L. 2010. Effects of rolling operations on cover crops termination, soil moisture, and soil strength in a southeastern US no-till system. In: Proceedings of the World Congress of Soil Science, August 1-6, 2010, Brisbane, Australia. CDROM.

Interpretive Summary: Mechanical termination of cover crops by rollers/crimpers allows planting cash crops into rolled residue three weeks after rolling. In the Southern US this period is needed for cover crops to be fully terminated so there is no competition for water and nutrients resources with a cash crop. Depending on year, especially in wet and cooler spring waiting three weeks would push back the cash crop planting too late and potentially affect its growth. In such weather, farmers in this region usually apply herbicide after rolling/crimping to speed-up cover crop termination. This option is not permitted, however, in organic production, thus repeatable rolling over the same area may be needed. Repeated rolling/crimping might contribute to increased soil compaction, which could result in suppressed cash crop growth. Results from this study showed that rolling two or three times did not increase soil compaction, and rolled residue kept soil strength (Cone Index) significantly lower compared to standing cover crops due to cover crop termination and moisture conservation. Soil water content after three rolling operations was significantly higher compared with standing rye and the mixture. Multiple rolling can be beneficial for faster mechanical termination of single cover crops but may not be adequate for mixtures that include hairy vetch because this legume cover had an ability to recover.

Technical Abstract: In the Southern US, three weeks are typically needed after rolling/crimping cover crops before planting cash crops in no-till systems. To enhance cover crop termination, a supplemental application of herbicide is usually needed. However, herbicides cannot be used in organic production, thus requiring additional rolling operations, but multiple rolling operations might contribute to soil compaction, which could be detrimental for cash crop development. Our objectives were to determine the effectiveness of two roller designs in terminating rye and a mixture of rye, crimson clover, and hairy vetch in multiple rolling operations, and the effects on volumetric moisture content (VMC) and soil strength. In three growing seasons (2007- 2009), two weeks after rolling, both roller designs terminated rye above 90%, which was the recommended rye termination rate to plant a cash crop. Rolling two or three times did not cause additional soil compaction, and rolled residue kept soil strength significantly lower compared to standing cover crops due to soil moisture conservation. Results indicated that VMC after three rolling operations was significantly higher compared with standing rye and the untreated mixture. Multiple rolling can be beneficial for faster mechanical termination of cover crops but may not be adequate for mixtures that include hairy vetch.