|Richard Jr, Edward|
|Waguespack, Herman - ASCL, THIBODAUX, LA|
|Jackson, Windell - ASCL, THIBODAUX, LA|
Submitted to: American Society of Sugar Cane Technologists
Publication Type: Abstract Only
Publication Acceptance Date: May 9, 2007
Publication Date: June 11, 2007
Citation: Viator, R.P., Johnson, R.M., Richard Jr, E.P., Waguespack, H.L., Jackson, W. 2007. Sugarcane Post-harvest Residue Retention and Certain Ripener Applications Reduce First and Second Ratoon Yields [abstract]. Journal of the American Society of Sugar Cane Technologists. 27:66. Technical Abstract: Retention of sugarcane (interspecific hybrids of Saccharum spp.) post-harvest residue and certain glyphosate ripener application regimes have independently been shown to reduce yields of the subsequent ratoon crop. The objective of this experiment was to determine the combined effects of post-harvest residue retention, ripener application, and ripener treatment-to-harvest intervals (THI) on yields of the treated first ratoon and the subsequent non-treated second ratoon. Whole plots consisted of either a non-treated control or a 0.21 kg a.e./ha application of glyphosate to first ratoon LCP 85-384 in 2003 and 2004. Split-plots consisted of THI of 40, 50, and 60 days for the first ratoon. Split-split plot treatments consisted of mechanical repositioning of post-harvest residue into the wheel furrow compared with complete retention of residue in the second ratoon. At a 40 and 60 day THI, sucrose yield was not significantly increased due to ripener application, but at a 50 day THI glyphosate application increased sucrose yield by 740 kg/ha compared to the control in the first ratoon. In the second ratoon, there was a glyphosate by THI interaction on sucrose yield indicating that these stresses do compound each other. For glyphosate-treated cane, harvesting at a 60 day THI in the first ratoon reduced cane yield of the second ratoon by 4.9 and 6.0 Mg/ha and sugar yields by 900 and 950 kg/ha compared to the 40 and 50 THI, respectively. Furthermore, waiting until a 60 day THI reduced sucrose yields by 300 kg/ha compared to the non-treated control in the second ratoon. The fact that there were no interactions between post-harvest residue retention and ripener application on yields of the subsequent second-ratoon crop indicates that these stresses act independently of each other. Full residue retention reduced cane and sucrose yield by 2.3 Mg/ha and 300 kg/ha compared to partial removal. Until residue tolerant varieties are identified, producers should remove post-harvest residue to mitigate yield losses in subsequent ratoons. In addition, delaying the harvest of ripener-treated cane due to uncontrollable climatic conditions until a 60 day THI will negate the yield advantage associated with a ripener application in the harvested crop and will decrease yields in the subsequent crop. The use of multiple varieties in a harvesting management program could eliminate some of the harvesting of cane at non-optimal THI. The use of naturally high sucrose varieties such as L 97-128 and HoCP 00-950 without a ripener application could be used to buffer against non-optimal THI for ripener-treated cane.