Biomass sorghum and maize have similar water-use-efficiency under non-drought conditions in the rain-fed Midwest U.S.

Roby, M.; Fernandez, Maria G. Salas; Heaton, Emily A.; Miguez, Fernando E.; VanLoocke, Andy

doi:10.1016/j.agrformet.2017.08.019

Cited by 24 publications

(38 citation statements)

References 74 publications

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“…With regards to WUE, Singh and Singh (1995) and Farré and Faci (2006) have reported a similar range of values for maize, sorghum, and pearl millet, with a slight advantage for sorghum under water stress. Zegada-Lizarazu et al (2012) found that sweet sorghum had higher WUE than maize under water deficit, and similar results were reported by Bhattarai et al (2020) and Roby et al (2017) . However, few genotypes were used in these studies compared to the 36 that we used.…”

Section: Discussionsupporting

confidence: 79%

Transpiration efficiency: insights from comparisons of C4 cereal species

Vadez

Choudhary

Kholová

et al. 2021

Journal of Experimental Botany

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An earlier review on transpiration efficiency (TE) reported a tight link between high TE and transpiration restriction under high vapor pressure deficit (VPD). This paper builds on it and addresses other factors altering TE (shoot biomass/water transpired), namely species difference among major C4 cereals, soil texture, and source/sink relationships. Maize genotypes (n=10) had overall higher TE than pearl millet (n=10), and somewhat higher than sorghum (n=16). TE was higher in high clay- than in sandy soil, and that effect was crop-dependent. Maize showed large TE and yield variations among soils, while pearl millet TE showed no soil variation. This also suggested specific soil-species fitness. Removal of cobs drastically decreased TE in maize, but not in pearl millet, suggesting that source/sink balance also drove TE variations. The species differences in TE are interpreted to account for differences in transpiration restriction capacity under high VPD but also to breeding history having possibly favored maize’s source/sink balance, suggesting a breeding scope to increase TE in pearl millet and sorghum. The soil results open a new avenue to better understand stomatal regulation and transpiration restriction under high VPD leading to TE differences, where considering soil hydraulic characteristics and root system together appears to be critical. Finally, the results on sink alteration highlight the importance of sink strength in regulating transpiration / photosynthesis and consequently in influencing TE.

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Section: Discussionsupporting

confidence: 79%

Transpiration efficiency: insights from comparisons of C4 cereal species

Vadez

Choudhary

Kholová

et al. 2021

Journal of Experimental Botany

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“…Sorghum is less susceptible to drought than maize and has higher water‐use‐efficiency than other C 4 crops (Farré & Faci, 2006; Katerji & Mastrorilli, 2014; Steduto et al, 1997; Zegada‐Lizarazu, Zatta, & Monti, 2012), indicating the potential for greater capacity for O 3 detoxification relative to stomatal O 3 uptake. However, other studies have shown that sorghum and maize have similar water‐use‐efficiency when water is non‐limiting (Farré & Faci, 2006; Roby, Fernandez, Heaton, Miguez, & VanLoocke, 2017). Overall, intraspecific variation in O 3 tolerance is still unclear at a mechanistic level and will require future studies investigating plant response to O 3 at both species and genotypic level.…”

Section: Discussionmentioning

confidence: 97%

Bioenergy sorghum maintains photosynthetic capacity in elevated ozone concentrations

Moller

Mitchell

et al. 2021

Plant Cell & Environment

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Elevated tropospheric ozone concentration (O3) significantly reduces photosynthesis and productivity in several C4 crops including maize, switchgrass and sugarcane. However, it is unknown how O3 affects plant growth, development and productivity in sorghum (Sorghum bicolor L.), an emerging C4 bioenergy crop. Here, we investigated the effects of elevated O3 on photosynthesis, biomass and nutrient composition of a number of sorghum genotypes over two seasons in the field using free‐air concentration enrichment (FACE), and in growth chambers. We also tested if elevated O3 altered the relationship between stomatal conductance and environmental conditions using two common stomatal conductance models. Sorghum genotypes showed significant variability in plant functional traits, including photosynthetic capacity, leaf N content and specific leaf area, but responded similarly to O3. At the FACE experiment, elevated O3 did not alter net CO2 assimilation (A), stomatal conductance (gs), stomatal sensitivity to the environment, chlorophyll fluorescence and plant biomass, but led to reductions in the maximum carboxylation capacity of phosphoenolpyruvate and increased stomatal limitation to A in both years. These findings suggest that bioenergy sorghum is tolerant to O3 and could be used to enhance biomass productivity in O3 polluted regions.

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“…The addition of lower peak growing season ET from energy sorghum compared to maize, despite the higher soil moisture in the energy sorghum plot that should promote higher ET, reflects the WUE and subsequent drought tolerance of energy sorghum (Mullet et al, 2014), which lends it to potential expansion across a wider climatic growing region than maize (Gelfand et al, 2013; Maw et al, 2017). While some studies have shown little difference in ET and WUE between maize and a hybrid energy sorghum–sudangrass variety (Roby et al, 2017), others have indicated energy sorghum's water demand is offset by its high productivity and thus WUE (Oikawa et al, 2015). Our WUE results suggest that energy sorghum does indeed produce a large amount of biomass per water volume used in the Midwest region (Table 2; Figure 4c), which highlights the climatic flexibility of energy sorghum as a bioenergy feedstock.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2020

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Perennial crops have been the focus of bioenergy research and development for their sustainability benefits associated with high soil carbon (C) and reduced nitrogen (N) requirements. However, perennial crops mature over several years and their sustainability benefits can be negated through land reversion. A photoperiod‐sensitive energy sorghum (Sorghum bicolor) may provide an annual crop alternative more ecologically sustainable than maize (Zea mays) that can more easily integrate into crop rotations than perennials, such as miscanthus (Miscanthus × giganteus). This study presents an ecosystem‐scale comparison of C, N, water and energy fluxes from energy sorghum, maize and miscanthus during a typical growing season in the Midwest United States. Gross primary productivity (GPP) was highest for maize during the peak growing season at 21.83 g C m−2 day−1, followed by energy sorghum (17.04 g C m−2 day−1) and miscanthus (15.57 g C m−2 day−1). Maize also had the highest peak growing season evapotranspiration at 5.39 mm day−1, with energy sorghum and miscanthus at 3.81 and 3.61 mm day−1, respectively. Energy sorghum was the most efficient water user (WUE), while maize and miscanthus were comparatively similar (3.04, 1.75 and 1.89 g C mm−1 H2O, respectively). Maize albedo was lower than energy sorghum and miscanthus (0.19, 0.26 and 0.24, respectively), but energy sorghum had a Bowen ratio closer to maize than miscanthus (0.12, 0.13 and 0.21, respectively). Nitrous oxide (N2O) flux was higher from maize and energy sorghum (8.86 and 12.04 kg N ha−1, respectively) compared with miscanthus (0.51 kg N ha−1), indicative of their different agronomic management. These results are an important first look at how energy sorghum compares to maize and miscanthus grown in the Midwest United States. This quantitative assessment is a critical component for calibrating biogeochemical and ecological models used to forecast bioenergy crop growth, productivity and sustainability.

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Biomass sorghum and maize have similar water-use-efficiency under non-drought conditions in the rain-fed Midwest U.S.

Cited by 24 publications

References 74 publications

Transpiration efficiency: insights from comparisons of C4 cereal species

Transpiration efficiency: insights from comparisons of C4 cereal species

Bioenergy sorghum maintains photosynthetic capacity in elevated ozone concentrations

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

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