Biomass yield potential and nitrogen use efficiency of the photoperiod-sensitive energy sorghum

Recently introduced high-yield energy sorghums (Sorghum bicolor L. Moench) have great potential to be dedicated lignocellulosic biofuel feedstocks. Nitrogen (N), the key nutrient for plant growth and development, is the primary input and cost for an energy sorghum production system. In order to maximize the biomass yield with reasonable N inputs, it is essential to optimize management practices to improve N use efficiency (NUE) for biomass production based on different hybrids and environment (H x E x M). Thus, the objectives of this study were to evaluate the effects of N fertilization on biomass yield and feedstock composition, and to determine optimal N rates on energy sorghum hybrids and the environment. Four hybrids with different photoperiod-sensitivity (TX08001, TX17500, TX17600, TX17800) were studied for yield potential and N response under four N rates (0, 56, 112, 168 kg N ha-1) using aqueous urea ammonium nitrate (UAN: 32-0-0) in two locations (Urbana, IL and College Station, TX) in 2018 and 2019. The experimental design was a split-plot within a randomized complete block design with four replications. The N treatment was the main plot factor, and the hybrid was sub-plot factor. Sorghum was planted at 180,000 seeds ha-1 on soybean stubble using a precision planter. Location, year, and hybrid significantly influenced the biomass yield. Comparisons among four hybrids showed no consistent pattern for annual biomass yield was observed in different years and locations. Weather variations played a substantial role to influence biomass yield potential and their response to N inputs, especially in TX. In TX, the cumulative precipitation was lower in 2018 (188 mm) than 2019 (526 mm) during the growing season (April to August), resulting in lower biomass yield across all hybrids in 2018 (16 Mg DM ha-1 in 2018 vs. 22 Mg DM ha-1 in 2019). Biomass tissue N concentrations indicated that energy sorghum requires a minimum of approximately 7 kg N to produce each one Mg of biomass. These results suggest energy sorghum can utilize available N from the soil and soil test for available N should be done before the application of N fertilizer. NIE was estimated from the overall biomass yield (averages across location, year, and hybrid), which significantly increased with increasing N rate, and the highest NIE (~ 31 kg kg-1) was observed at the N rate of 56 kg-N ha-1. Growing season not only played a role in biomass yield; but, chemical composition as well. Concentrations of structural components were significantly lower than the other three environments (IL-2018, IL-2019, and TX-2018) in TX-2019. Hybrid choice effected chemical composition as well. TX17800 consistently contained greatest concentration of structural components and TX17600 had lower structural/higher soluble concentrations among the four hybrids.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Crop Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2020

Author dc:creator

• Schetter, August Anton

Contributors dc:contributor

• Lee, DoKyoung
• Below, Frederick E
• Moose, Stephen P

• biomass
• energy
• sorghum
• nitrogen
• photoperiod

Statement dc:rights

• Copyright 2020 August Schetter

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/108202

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/108202