"green" sugarcane harvesting on biomass and sugar ... - PubAg - USDA

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The effect of the world-wide change from burnt to unburnt "green" sugarcane harvesting on ..... Southern Regional Research Center in New Orleans, Louisiana.
The effect of the world-wide change from burnt to unburnt "green" sugarcane harvesting on biomass and sugar processing has not been fully characterized, particularly quantity and quality differences among trash tissues. Whole-stalks from the first ratoon crop (12 months age) of five commercial Louisiana sugarcane varieties (LCP 85-384, HoCP 96-540, L 97-128, l 99-226, and l 99-233) with varying yield and harvest characteristics, including lodging and leaf sheath adherence, were harvested mid-season. Four sample tissues from four replicates were collected: brown, dry leaves (Bl), green leaves (Gl), growing point region (GPR) or apical internodes, and stalk (5). Juice was extracted from each tissue type. Total trash on a wet weight basis (GPR + GL + Bl) ranged from 16.4 to 19.8% with variety and generally reflected leaf sheath adherence. Over one third (av. 36.3%) of the total dry biomass from sugarcane was from the trash, with GL delivering the most biomass of all the trash tissues. A strong negative correlation (R'::: -0.909) existed between ash in the Bl and 5 juices which suggests that before BL fell from the field stalk, soluble inorganic nutrients were re-assimilated back into the S. Thus, even though varieties ability to "self-remove" or "shuck" Bl in the field before harvesting is a minor selection criterion in breeding programs, there may be no overall loss in inorganic nutrients being delivered to the factory. Starch concentrations (ppm/Brix) in the 5 were low, but when calculated on a percent tissue wet wt basis it was observed that the S delivers a considerable amount of the starch to the factory just because of its much higher weight than other tissues. Therefore, the impact of starch in stalks delivered to the factory should not be underestimated. On a percent tissue wet wt basis, 5 and Gl delivered the most total soluble polysaccharides to the factory. A significant correlation (R' 0.63, P:::iUtt::> uy UIIIl;;::It'lll UU ~U!:::ldluaIIO' VClIICUO~

FigUi'0 4. Average total polysaccharide content of different tissues from five Louisi,ma sugarcane varieties quoted on a tissue wet weight basis

strong impact on the starch load to

the factory (Alexander, 1973). - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - , Generally, as a sugarcane variety

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starch concentrations the S were low, when a percent tissue wet wt observed that the S

actually delivers a considerable, load of starch to the factory just because of the much higher weight of S to other

ability to have loose BL or 'self-remove' BL in the field belore harvest­

tissues. Therefore, the impact of starch in stalks delivered to the

Ing is a minor selection criterion in breeding programs, there may be no overall loss in soluble inorganic nutrients being delivered to the factory. This conclusion is reinforced by L 99-233' and L 99-226 haVing higher % ash in their theoretical global juice at 5.2 and %,

factory should not be underestimated. On a percent tissue wet wt basis, Sand GL delivered the most soluble polysaccharides to the

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respectively, than LCP 85-384 (3.9%) and HoCP 96-540 (5.0%). L 97-128 theoretical global juice contained 4.1 % - but this low value was mostly because of the lower ash in its GL rather than S. Full confirmation of this conclusion will be gained by follOWing the fate of a radioactive inorganic salt across sugarcane growth. Overall, results suggest that although breeding for the self­ removal of BL is advantageous to growers for improved cleaning of the stalks by the combine harvester it is not as advantageous to processors as previously considered because a similar amount of soluble ash will still be delivered to the factory in the stalks. In a previous study (Eggleston et ai, 2007) it was observed that that soluble irnpurities in BL were being assimilated back into the sugarcane plant during ongoing leaf senescence. Nevertheless, BL pose other processing problems to the factory which includes

factory. A significant correlation (R' = 0.63, PKAYHapOAlibl(:1 caxapHbl~ >KypHan, 2009 r., TOM 111, NQ 1322