Integration of Optical Remote Sensor-Based Yield Prediction and Impact of Nitrogen Fertilization, Harvest Date, and Planting Scheme on Yield, Quality, and Biomass Chemical Composition in Energy Cane Production in Louisiana

The established sugarcane industry in Louisiana is perceived as an advantage for biofuel industry because of the similarities of energy cane and sugarcane by way they are cultivated, harvested, and processed. This study was conducted at the LSU AgCenter Sugar Research Station in St. Gabriel, LA from 2013-2015 to evaluate the influence of planting scheme, N rate, and harvest date on energy cane yield, quality parameters, nutrient uptake, and biomass chemical composition. The relationship of vegetation indices (VI) with stalk, fiber yield, and N uptake of energy cane harvested at different dates was also evaluated. The experiments consisted of variety (Ho 02-113, US 72-114), N rate (0, 56, 112, and 224 kg N ha-1) and harvest date (one- and two- months earlier harvest and scheduled harvest) as treatments arranged in split-split plot in a randomized complete block design with four replications. Another experiment was conducted with planting scheme (whole stalks vs. billets) and variety (Ho 02-113, US 72-114, Ho 06-9001, Ho 06-9002, L 01-299, and L 03-371) as factors arranged in split plot in randomized block design with four replications. Energy cane yield, quality parameters, chemical composition, and nutrient concentration and uptake were significantly affected by harvest date only. Both N rate and planting scheme did not affect biomass yield and quality. The nutrient removal rates between planting scheme were similar but not among harvest dates and varieties suggesting that the fertilizer recommendation will remain virtually the same for whole stalk- and billet-planted energy cane. The Pearson correlation analysis showed a strong dependence between VIs (i.e., simple ratio, normalized difference vegetation index) computed from reflectance readings at 670 (red) and 705 (red-edge) nm and stalk yield, N uptake, and fiber yield across cane age. The outcomes of this study show the: a) applicability of sugarcane cultural management practices for energy cane production, b) potential use of optical remote sensing in energy cane stalk and fiber yield prediction, and c) several areas of research emphasis to pursue for future studies on energy cane