Producing biomass: Biomass types: Crops: Sweet sorghum
Sweet sorghum is a relatively new crop to Australia but is becoming popular with growers who want to grow it for biofuel processing.

Benefits of growing sweet sorghum

Sweet sorghum produces less grain but more biomass than grain sorghum. Unlike many other crops used for renewable energy production, sweet sorghum can simultaneously produce food and energy products.

Agrifuels examines the different uses of sweet sorghum.

The grain can be used as a gluten-free human food product, an animal feed, or processed into ethanol.

The stalk has a high concentration of fermentable sugars at a level similar to sugarcane, and can be used as a feedstock for ethanol production.

The residual fibre (bagasse) from sweet sorghum can be used to produce electricity, paper, and cattle fodder.
Sweet sorghum can out-yield canola by up to 30% during very dry years.
Renewable products such as green chemicals and polymers can also be produced from components of the sweet sorghum crop, many of which can replace comparable items produced from fossil fuel feedstocks.

Evaluating the economics of growing sweet sorghum

Sweet sorghum – Opportunities for a new renewable fuel and food industry in Australia, published by RIRDC in 2013, also examines the opportunities to develop a sweet sorghum industry in Australia.

The report:
  • analyses the agronomy of sweet sorghum
  • demonstrates the production of energy, food, and feed products from sorghum
  • assesses the potential economic benefits of sweet sorghum biorefineries in the Australia
  • maps out the life cycle of sweet sorghum biorefinery products
  • asseses the potential for integrating sweet sorghum and sugarcane processing.
The results show that there are significant opportunities for developing sweet sorghum industries in Australia, particularly through integration with the sugarcane production and processing industries.
This report is targeted at agricultural producers and agro-industrial companies seeking opportunities to create value in the bioeconomy. It is also of use to researchers investigating new biomass feedstocks for producing biofuels, biochemicals and renewable bioproducts.

Growing sweet sorghum

Although sweet sorghum is believed to have originally developed in tropical regions, it also grows well in temperate climates.

Compared to sugarcane, sweet sorghum requires less fertiliser and water to produce significant biomass. It also has a higher tolerance to salt and drought.

The Queensland Department of Agriculture, Fisheries and Forestry provides a guide to sorghum varieties and planting methods as well as comprehensive information on nutritional inputs and disease management.

The Department of Primary Industries, NSW, provides a similar best management practices fact sheet for grain sorghum [PDF 879 kb].

Although sorghum is not widely grown in Western Australia, the Department of Agriculture, WA, has a sorghum growing factsheet for WA growers [PDF 42 kb].

Sweet sorghum – Opportunities for a new renewable fuel and food industry in Australia (Section 2), describes sowing and management methodologies used for a field trail.

Managing sorghum for high yields [PDF 1.2 MB], also provides growers with best practice strategies to improve yields of grain sorghum.

The guide provides information on:
  • fallow management strategies
  • planting time and optimal row spacings
  • nutrition and fertiliser strategies
  • weed and pest control.

Harvesting sweet sorghum

The Department of Agriculture, Fisheries and Forestry has information on Sorghum – Nutrition, irrigation and harvest issues, which includes:
  • when to harvest
  • header settings
  • pre-harvest spraying.


Sweet sorghum – Opportunities for a new renewable fuel and food industry in Australia (Section 3.2), describes the benefits and risks of:
  • harvesting the stalk with the seed head retained
  • removing the seed heads during harvest.

Supplying sweet sorghum

One of the major advantages of growing sweet sorghum is that the major components of the crop can be used to generate multiple, value-added products such as food and feed products, and fuel and energy products.

Sweet sorghum – Opportunities for a new renewable fuel and food industry in Australia, looks at the typical transport costs for sorghum (see Section 1.6.2).

A critical parameter determining the economics of integrating sweet sorghum into the sugarcane cropping/processing system is the transport distance to the factory.

Contacts

Heather Bone

RebusJ Sustainability

50 Willowvale Drive, Willow Vale , Queensland 4209
Phone: 0400473733

heather.bone@hotmail.com
ADI Systems Ltd

ADI Systems

ADI Systems (Asia Pacific), 50 Yeo Street, Neutral Bay, NSW 2089
Phone: 1.800.751.806 (toll free)

asiapacific@adi.ca
Prof. Christopher Grof

University of Newcastle

Biological Sciences Callaghan, University Drive, Callaghan, NSW 2308
Phone: (02) 4921 5858

Chris.Grof@newcastle.edu.au
Andrew Borrell

Queensland Alliance for Agriculture & Food Innovation

Hermitage Research Facility, Warwick, Queensland,
Phone: 07 4660 3640

a.borrell@uq.edu.au
Ian O’Hara

Centre for Tropical Crops and Biocommodities

Queensland University of Technology, Brisbane, Queensland 4000,
Phone: 07 3138 1551

i.ohara@qut.edu.au