Location: Sugarcane Research Unit
Title: Impact of tillage frequency, post-harvest residue management, and herbicide placement on bermudagrass interference in sugarcane Authors
|Richard Jr, Edward|
Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: January 3, 2011
Publication Date: February 1, 2011
Citation: Dalley, C.D., Richard Jr, E.P., Viator, R.P. 2011. Impact of tillage intensity, post-harvest residue management, and herbicide placement on bermudagrass interference in sugarcane. Proceedings Weed Science Society of America Meeting, Portland, Oregon. February 7-19, 2011. p. 305. Available: http://wssaabstracts.com/public/4/abstract-305.html. Technical Abstract: Bermudagrass is a difficult to manage perennial weed ubiquitous to Louisiana sugarcane fields. Studies conducted near Houma, LA, evaluated the impact of crop management practices on the spread of bermudagrass and sugarcane production. Three tillage frequencies were compared: standard tillage, reduced tillage, and no-till. Standard tillage, using a rolling disk cultivator, included four tillage applications: mid-March, mid-April following fertilizer injection, mid-May and early-June. Reduced tillage had two tillage applications: following fertilizer injection and in early-June. In no-till, there was no additional tillage after the crop was planted. Green harvesting sugarcane deposits 13 to 22 Mg/ha of extraneous leaf materials uniformly onto sugarcane fields. In Louisiana’s climate, this post-harvest residue has been shown to be detrimental to the growth and establishment of subsequent ratoon crops and its removal is recommended; accomplished mostly through burning. Three post-harvest residue management practices were compared: no residue removal, removal by burning, and removal from the row top with a rotating brush, moving residue into the wheel furrow. Band-application of herbicides in early-spring, in combination with row side tillage, is a common practice in Louisiana sugarcane production due to its cost savings. However, reducing tillage frequency, when combined with band-application, may increase spread of bermudagrass. Two spring herbicide application methods [metribuzin (2.8 kg ai/ha) plus pendimethalin (2.8 kg ai/ha)] were compared: broadcast-application, band-application; both were compared to no herbicide application. Bermudagrass infestations were visually evaluated in the ratoon crops. Cultivation and herbicide application method interacted in their impact on bermudagrass infestation. Under conventional tillage practices, broadcast- and band-applications had similar bermudagrass cover in the first (16 and 17%) and second ratoons (13 and 14%), with slightly higher percent cover in banded (22%) verses broadcast (15%) in the third ratoon. Bermudagrass cover was greatest under no-till for all herbicide application methods, and was more than 90% cover when no herbicide was applied. Banding herbicides, combined with reduced tillage, resulted in higher bermudagrass cover compared to standard tillage in all three ratoon crops. Post-harvest residue management did not affect bermudagrass cover. It was hypothesized that retaining the residue may protect the bermudagrass from freezing winter temperatures allowing it to resume growth earlier than when residue was removed and/or that the residue may interfere with herbicide applications. The results of this study do not support either theory. Sugar yields were affected by all three management practices, with an interaction between cultivation and herbicide applications. In plant cane, yields were less only under the combination of no-till and no herbicide application. In the ratoon crops, banding herbicides only resulted in lower yields under no-till, while reduced tillage only resulted in lower yields when no herbicide was applied. With few exceptions, reduced and standard tillage had similar yields. Yields were always lower when using no-till. When no-till was practiced, total yields for the crop cycle were reduced 11% when herbicides were applied broadcast, 15% when banded, and 25% when no herbicide was applied. When post-harvest residues were not removed yields were reduced 5, 6, and 10% in the first, second, and third ratoon, respectively, compared with removal by burning; removal by brushing was intermediate. Reducing the frequency of tillage from four to two applications appears to be a viable option for growers, even when band-applying herbicides, although adopting a no-till strategy in sugarcane seems less viable.