Elsevier

Renewable Energy

Volume 129, Part A, December 2018, Pages 328-333
Renewable Energy

Sweet sorghum (Sorghum bicolor [L.] Moench) a potential biofuel feedstock: Analysis of cultivar performance in the Mid-Atlantic

https://doi.org/10.1016/j.renene.2018.06.004Get rights and content

Highlights

  • Sweet sorghum grown as potential biofuel crop in the U.S. Mid-Atlantic.

  • Cultivars with the highest potential as biofuel feedstocks were Dale, Della, Keller, KN Morris and M81E: theoretical ethanol yield from 1000 – 1149 L ha−1.

  • Of these cultivars, Della, M81E and KN Morris had the highest grain yield (1.94 – 2.41 Mg ha−1).

  • Potential problems include lodging and grain loss to birds.

Abstract

Sweet sorghum (Sorghum bicolor) was tested as a potential biofuel crop in the U.S. Mid-Atlantic. All studies were conducted on private farmland in Wicomico Co., on Maryland's Eastern Shore. In total, twelve cultivars were tested: Dale, Della, 
E2324, High Kane II, Keller, KN Morris, M81E, Mennonite, Simon, Sugar Drip, Theis and Topper 76-6. Eight cultivars were grown each year, over three years, and poorly performing cultivars were replaced. The five cultivars with the highest potential as biofuel feedstocks were Dale, Della, Keller, KN Morris and M81E. Biomass ranged from 52.9 to 64.1 Mg ha−1, juice volume from 14.0 to 22.8 Mg ha−1, Brix from 13.1 to 15.1 and theoretical ethanol yield from 1000 to 1149 L ha−1. Theoretical ethanol yield was ca. ⅓ that of grain corn grown in Maryland over the study period (2776–3798 L ha−1). Of these cultivars, Della, M81E and KN Morris had the highest grain yield (1.94–2.41 Mg ha−1). Further studies should focus on increasing ethanol yield through the improvement of agronomic practices, efficient juice extraction and the use of the “whole-crop” (juice, grain and bagasse) to generate ethanol. Potential problems for growers include lodging, particularly in areas with high winds, and grain loss to birds.

Introduction

World fuel ethanol production in 2013 was 88.7 billion liters with the two largest producing countries being the US at 50.3 billion liters and Brazil at 23.7 billion liters [1]. Fuel ethanol production in the U.S. is projected to continue to increase, but at a slower pace than over the period 2005–2010 [2]. In the U.S. corn is the main feedstock for fuel ethanol accounting for ∼95% of production [3]. Sweet sorghum may be a viable alternative to corn, as its energy ratio (output/input) for the production of fuel ethanol is similar to that of sugarcane (2.23 vs. 2.42), and much higher than that of corn, 1.30 [4]. Sweet sorghum is drought tolerant, requiring less than half of the water needed for corn. It also grows well on marginal, non-irrigated land as far north as southern Canada. It is known as the “camel among crops” due to its “wide adaptability, its marked resistance to drought and tolerance of both saline-alkaline soils, and waterlogging” [[5], [6], [7]].

The farm gate production cost of sweet sorghum for fuel ethanol production is considerably lower than for corn [8], and when transportation and processing costs are included fresh processed sweet sorghum is cost competitive with corn [9]. The State of Maryland passed the Water Quality Improvement Act of 1998 [10] to minimize runoff and leaching of nitrogen and phosphorus from farms into the Chesapeake Bay. Gen et al. [11] reported that sweet sorghum needed only 36% of the fertilizer N required for corn. Decreased nitrogen loading in the Chesapeake Bay, was linked to increased abundance and diversity of native SAV species [12]. Sweet sorghum may also be of use for the phytoremediation of high phosphorus soils, typical of Maryland's Eastern Shore poultry producing farms [13].

A report commissioned by the governors of eleven Mid-Atlantic and Northeast States to develop a low carbon fuel standard stated “the transition to lower carbon fuels could provide important energy security, climate change, and economic benefits in the region.” [14]. The use of fuel ethanol can reduce carbon emissions and improve air quality in urban areas [15]. The aim of this study was to determine cultivar suitability as feedstocks for fuel ethanol production in the Mid-Atlantic region, a first step in the establishment of biofuel production from sweet sorghum.

Section snippets

Experimental design

Three years (2009, 2010, and 2011) of field trials were conducted on Solar Fruits Biofuels farm located seven miles west of Salisbury MD (38° 20′ 48″ N, 75° 41′ 15″ W). The study site was a Hammonton sandy loam (0–2% slope; coarse-loamy, siliceous, semiactive, mesic Aquic Hapludults) with a minor presence of Hurlock sandy loam and Ingleside loamy sand. Mean soil test values for 2009–2011 were: pH 5.9, OM 1.1%, P 95.1 mg kg−1, K 115.2 mg kg−1, Ca 425.9 mg kg−1 and Mg 96.9 mg kg−1 (Mehlich 3).

2009

The following cvs were planted in 2009: Dale, Della, High Kane II, Keller, KN Morris, M81E, Mennonite and Sugar Drip. Biomass, Juice volume, Brix and Theoretical Ethanol yield varied with both Cv and CropSys (Table 1). As shown in Table 2, both Biomass and Juice Volume were highest for cvs Dale, Della, Keller, KN Morris and M81E (Biomass [mean ± SD], 64.1 ± 2.3 Mg ha−1and Juice volume, 22.8 ± 2.3 m3 ha−1), while Dale, Keller, KN Morris, and M81E had the highest Brix (15.5 ± 0.7). Theoretical

Discussion

Averaged over the three yr study, the following cvs produced the highest Theoretical Ethanol yield: Dale, Della, Keller, KN Morris, M81E, (1000–1149 L ha−1). Not surprisingly in sweet sorghum, Theoretical Ethanol yield was dependent on Juice volume (r = 0.939. P < 0.001) and Brix (r = 0.346, P < 0.001). Theoretical Ethanol yield was similar to that reported from Virginia [19]. This is the most comparable study to ours, as it is the closest geographically (ca. 202 km, southwest) and used a

Conclusions

The cultivars with the highest potential as feedstocks for ethanol production in the mid- Atlantic are Dale, Della, Keller, KN Morris, M81E (canes only). Della, M81E and KN Morris are the best cultivars if you harvest both the canes and grain as sources-of-ethanol. Due to their height and sandy nature of the soils, these cultivars, particularly Della are generally susceptible to lodging under wet and stormy conditions. Theoretical Ethanol Yield for these cultivars ranged from 1000 to 1149 L ha−1

Acknowledgements

We thank the Maryland Grain Producers Utilization Board (MGPUB) for funding this project; Jeffrey Benner, (Solar Fruits Biofuels) for use of the land; Henry Oakley (Venture Manor Farms) for preparing the field and planting the seeds; David Armentrout and Ron Mulford (Lower Eastern Shore Education and Research Center, University of Maryland) for providing the thresher; Karl Wardlow (Coffey Forage Seeds) for providing the hybrid [E2324]; Andrew Bell, Matt Blackwell, Abdi Geleta, Kristen King,

References (47)

  • S. Audilakshmi et al.

    Inheritance of sugar concentration in stalk (brix), sucrose content, stalk and juice yield in sorghum

    Biomass Bioenergy

    (2010)
  • J.A. Linton et al.

    Economic feasibility of producing sweet sorghum as an ethanol feedstock in the southeastern United States

    Biomass Bioenergy

    (2011)
  • C.A. Barcelos et al.

    Sweet sorghum as a whole-crop feedstock for ethanol production

    Biomass Bioenergy

    (2016)
  • S.I. Mussatto et al.

    Technological trends, global market, and challenges of bio-ethanol production

    Biotechnol. Adv.

    (2010)
  • U.S. Department of Energy

    Energy Efficiency & Renewable Energy. Alternative Fuels Data Center

    (2015)
  • USDA

    USDA Agricultural Projections to 2022. Office of the Chief Economist, World Agricultural Outlook Board, U.S. Department of Agriculture. Prepared by the Interagency Agricultural Projections Committee. Long-term Projections Report OCE-2013-1

    (2013)
  • C.M. Drapcho et al.

    Biofuels Engineering Process Technology

    (2008)
  • S. Chindaruksa et al.

    Bioethanol from Sweet Sorghum. A Review of Opportunities

    (2008)
  • FAO

    Sweet Sorghum in China

    (2002)
  • B.V.S. Reddy et al.

    Sweet sorghum: a water saving bio-energy crop

  • A.S. Bennett et al.

    Farm-Gate production costs of sweet sorghum as a bioethanol feedstock

    T. ASABE

    (2008)
  • Maryland

    House Bill 599: Water Quality Improvement Act of 1998

    (1998)
  • S. Gen et al.

    Potential yields and on-farm ethanol production cost of corn, sweet sorghum, fodderbeet, and sugarbeet

    J. Agron. Crop Sci.

    (1989)
  • Cited by (15)

    • Effects of harvest time on bioethanol production and bagasse characteristics for combustion and forage in sweet sorghum

      2022, Field Crops Research
      Citation Excerpt :

      The potential for the production of starch-based bioethanol using the grain was not taken into consideration in this current research due to the difficulty in simultaneously harvesting of the grain and stems, and the fact that the crop was fed on by birds generally prevents a high volume of grain from being obtained per unit area in the cultivation of sweet sorghum (Briand et al., 2018). Calculation of the fresh bagasse yield (FBY) was performed by subtracting the JY from the FSY (Holou and Stevens, 2012; Briand et al., 2018) As a next step, 1000 g of the fresh bagasse samples were dried in an oven at a temperature of 60 °C, to a constant weight, so as to obtain the moisture content of the bagasse. Finally, the dried samples were ground fine enough that it could pass through a 1-mm screen.

    • Performance and genetic diversity of pre-commercial sweet sorghum hybrids in Central-Western and Southern Brazil

      2022, Renewable Energy
      Citation Excerpt :

      Even with these advantages, some limitations are still noted in industrial ethanol production when employing sweet sorghum concerning the composition of nutrients in the sorghum syrup during the maturation time of the plant [7]. In this sense, genetic diversity studies are useful allow for the understanding of the relationship and performance between sweet sorghum accessions and aid in defining strategies for the identification of superior parents for the development of new cultivars [5]. Biometric techniques are commonly used to estimate genetic divergence between accessions and various methodologies in this regard are available.

    • Whole sweet sorghum plant as a promising feedstock for biobutanol production via biorefinery approaches: Techno-economic analysis

      2020, Renewable Energy
      Citation Excerpt :

      Furthermore, the cultivation of sweet sorghum requires less fertilizer and water compared with other crops like sugarcane. These advantages of sweet sorghum make it a suitable feedstock for the production of biofuels in hot and dry areas [25–27]. This plant has free sugars mixture as a juice as well as starchy grain and lignocellulosic biomass (bagasse), all of which can be used for biofuel production [22,28].

    • Evaluation of different sweet sorghum cultivars for bioethanol yield potential and bagasse combustion characteristics in a semiarid Mediterranean environment

      2020, Biomass and Bioenergy
      Citation Excerpt :

      The value of 0.58 L represents the theoretical maximum yield of ethanol produced from the complete inversion of sucrose (hydrolysis of sucrose into glucose and fructose) and complete fermentation of all resulting and native glucose [30]. Potential starch-based bioethanol production from the grain was not considered in the present study, because it is difficult to harvest the grain and stem of the crop simultaneously, and feeding by birds generally inhibits obtaining a high amount of grain in sweet sorghum cultivation per unit area [31]. The fresh bagasse yield (FBY) was calculated by subtracting the JY from the FSY [31,32].

    • Sweet sorghum: A potential resource for bioenergy production

      2019, Refining Biomass Residues for Sustainable Energy and Bioproducts: Technology, Advances, Life Cycle Assessment, and Economics
    View all citing articles on Scopus
    View full text