Photoperiod Sensitive Energy Sorghum Responses to Environmental and Nitrogen Variabilities

Abstract

Recently introduced photoperiod-sensitive (PS) biomass sorghum (Sorghum bicolor L. Moench) needs to be investigated for their yield potentials under different cultivation environments with reasonable nitrogen (N) inputs. The objectives of this study were to 1) evaluate the biomass yield and feedstock quality of four sorghum hybrids with different levels of PS ranging from very PS (VPS) hybrids and to moderate PS (MPS) hybrids, and 2) determine the optimal N inputs (0~168 kg N ha-1) under four environments: combinations of both temperate (Urbana, IL) and subtropical (College Station, TX) regions during 2018 and 2019. Compared to TX, the PS sorghums in central IL showed higher yield potential and steady feedstock production with an extended daylength and with less precipitation variability, especially for the VPS hybrids. The mean dry matter (DM) yields of VPS hybrids were 20.5 Mg DM ha-1 and 17.7 Mg DM ha-1 in IL and TX, respectively. The highest N use efficiency occurred at a low N rate of 56 kg N ha-1 by improving approximately 33 kg DM ha-1 per 1.0 kg N ha-1 input. Approximately 70% of the PS sorghum biomass can be utilized for biofuel production, consisting of 58-65% of the cell wall components and 4-11% of the soluble sugar. This study demonstrated that the rainfed temperate area (e.g., IL) has a great potential for the sustainable cultivation of PS energy sorghum due their observed high yield potential, stable production, and low N requirements.

Ecosystem‐scale biogeochemical fluxes from three bioenergy crop candidates: How energy sorghum compares to maize and miscanthus

“…As a result, with higher soil moisture under energy sorghum, the mid‐season peak in N 2 O fluxes was higher for energy sorghum than maize, leading to comparable cumulative growing season N 2 O fluxes for the two crops. Recent evidence also suggests that optimum N fertilization rates for energy sorghum are approximately 56 kg N ha −1 (Maw et al, 2019; Schetter et al, 2020), which is closer to the rate applied to miscanthus in this study. It is therefore likely that our energy sorghum fertilization rate exceeded plant N requirements, and thus we would expect N 2 O losses to be reduced with less N addition in future.…”

An assessment of the potential for biomass sorghum to be produced as a dedicated bioenergy crop in Iowa, USA

“…A major agronomic and environmental issue to address with the production of a crop is how much nitrogen fertilizer should be applied. Prior field studies suggest that biomass sorghum does not require over 56 kg N ha -1 to produce high yields (Maughan et al, 2012;Schetter et al, 2020). Yield response to fertilizer applied can be simulated in Agro-IBIS through "FNOPT", a critical leaf nitrogen level parameter (below which nitrogen-stress occurs), as low levels have leaf nitrogen levels have been shown to inhibit plant growth (Archontoulis et al, 2012).…”