Location: Agroecosystem Management ResearchTitle: Sugarcane straw removal effects on plant growth and stalk yield Author
Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/27/2017
Publication Date: N/A
Citation: N/A Interpretive Summary: Crop residue remaining on the soil surface after harvest serves a number of functions including protection from wind and water erosion, modulation of heat and moisture exchange with the atmosphere, source of nutrients for subsequent crops, and as an energy source for soil biota. In sugarcane production systems there is interest in removing straw for other uses such as an energy source and a feedstock for cellulosic biofuel production. Little information is available regarding the effect of straw removal on other crop residue functions is available for sugarcane systems. A two-year study was conducted at two sites in a major sugarcane production region of Brazil to quantify the effect of straw removal on crop production and quality. Treatments included 0, 25, 50, 75, and 100% straw removal during two seasons (wet and dry). Sugarcane tillering, plant growth, final yield, and quality were measured. There were differences in plant growth between the wet and dry seasons but no differences in sugarcane yield or quality due to straw removal treatments. Retaining moderate amounts of straw to meet other soil functions would allow straw harvest to meet energy and feedstock demands.
Technical Abstract: There is growing interest in sugarcane straw removal from the field to use as raw material for bioenergy production. In contrast, sugarcane straw removal may have negative implications for many soil ecosystem services and subsequent plant growth. A two-year experiment was conducted at Bom Retiro and Univalem mills within the dry and wet seasons for assessing the impact of straw rates removal on plant production. The experimental design was randomized blocks with five treatments proportional to 0, 25, 50, 75 and 100% of straw removal. Plant parameters evaluated included: tillering, phytomass accumulation, stalk yield and stalk industrial quality. Straw removal increased plant tillering at Bom Retiro mill in both seasons and within dry season at Univalem mill, however the plant population at the end of each ratoon cycle was not affected by straw management. Phytomass yield across each ratoon cycle was fit to a sigmoidal model (R2 = 0.92, p < 0.05). Time necessary for plant completes its lag-phase is higher at the treatments applied in the dry season, whereas there was no time-pattern for plants to complete the linear and stationary growth phases. Moderate amounts of straw: 4 to 9 Mg ha-1 (dry base) on soil surface enhanced stalk yield. Different rates of straw removal does not affect stalk industrial quality. Overall, partial straw removal, at least in the short-term, could be a win-win situation, sustaining sugarcane yields and providing feedstock for bioelectricity cogeneration and/or 2G-ethanol production.