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ARS Home » Southeast Area » Houma, Louisiana » Sugarcane Research » Research » Publications at this Location » Publication #309351

Title: Potential losses of soil nutrients and energy content on the complete removal of sugarcane leaf material as a biomass feedstock

item White, Paul
item VIATOR, RYAN - Dow Agrosciences
item Webber Iii, Charles
item Eggleston, Gillian

Submitted to: Sugar Tech
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/13/2017
Publication Date: 2/20/2018
Citation: White Jr, P.M., Viator, R.P., Webber III, C.L., Eggleston, G. 2018. Potential losses of soil nutrients and energy content on the complete removal of sugarcane leaf material as a biomass feedstock. Sugar Tech. 20(1):40-49.

Interpretive Summary: Harvesting sugarcane in Louisiana is usually done with a combine chopper harvester. Billets are retained in a wagon and the leafy material is deposited on the soil surface. The amount of material can vary between 6 and 24 Mg ha-1. Unfortunately, as the leaf material decomposes it can release chemicals that harm the emerging cane. The “trash blanket” also keeps the soil cool and wet and slows down the next crop. If removed, the leaf material could be used as a bioenergy feedstock. However, by removing the leaf material we may also remove large amount of mineral nutrients and harm soil fertility. The purpose of this experiment was to determine how much leaf material is present in three commonly grown sugarcane varieties, and to measure the nitrogen, phosphorus, and potassium levels in the material. We collected leaves on five dates in 2009 and in 2010 from the Ardoyne Farm in Schriever, LA. Overall, the leaf material yield average was 11 Mg ha-1. The nitrogen, phosphorous, and potassium in the material amounted to 74, 9, and 83 kg ha-1 y-1, respectively. Replacing these nutrients lost could be costly to sugarcane growers. However, if the energy derived from the material is valued high enough, it could offset these losses. Future work will determine if removing nutrients in leaf material from fields lowers soil fertility enough that the fields require additional fertilizer.

Technical Abstract: Green-cane (unburnt) harvesting of sugarcane (Saccharum sp.) deposits between 6 – 24 Mg/ha of extraneous leaf material (residue) on the surface of soil. The removed leafy material has value as biomass for use as a potential second-generation biofuel or bioproduct feedstock. Negative aspects of crop residue removal, however, are well documented and include reduced subsequent crop ratoon yields, reduced soil quality, increased soil erosion, and loss of soil fertility. The objective of the study was to determine the yield and nutrient content of sugarcane leaf material harvested from three Louisiana, U.S.A., commercial sugarcane varieties HoCP 96-540, L 99-233, and L 99-226. Leafy material was harvested five times across two growing seasons: 2009 and 2010. Data varied by year due to weather conditions, but overall HoCP 96-540, L 99-226, and L 99-233 leaf yields were 11.5, 12.4, and 8.36 Mg/ha, respectively. Energy yields for HoCP 96-540, L 99-233, and L 99-226 were 190, 134, and 205 GJ/ha, based on bomb calorimeter measurements of leaf material valued at 16.5 MJ/kg. Average nitrogen, phosphorus, and potassium leaf nutrient yields that would not be returned to the soil were 74.0, 8.6, and 83.0 kg/ha/yr, respectively. Replacing these nutrients with chemical fertilizers would increase yearly fertilizer costs significantly. Overall, yields, and nutrient and energy contents of the sugarcane leaf material were similar to other potential second generation cellulosic feedstocks for biofuels, and bioproducts. Since only the leaf material would be used as a biofeedstock, sugarcane harvest for sugar would not be affected. Thus, multiple land use criteria could be achieved.