A preliminary investigation of the water use efficiency of sweet sorghum for biofuel in South Africa

Authors

  • MG Mengistu 1. Centre for Water Resources Research (CWRR), School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa; 2. South African Weather Service, Private Bag X097, Pretoria, South Africa
  • JM Steyn Department of Plant Production and Soil Science, University of Pretoria, Pretoria, South Africa
  • RP Kunz Centre for Water Resources Research (CWRR), School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
  • I Doidge African Centre for Crop Improvement (ACCI), School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
  • HB Hlophe Department of Plant Production and Soil Science, University of Pretoria, Pretoria, South Africa
  • CS Everson Centre for Water Resources Research (CWRR), School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
  • GPW Jewitt Centre for Water Resources Research (CWRR), School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
  • AD Clulow Centre for Water Resources Research (CWRR), School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa

DOI:

https://doi.org/10.4314/wsa.v42i1.15

Keywords:

water use efficiency, ethanol yield, biofuel crop, plant density, sweet sorghum, South Africa

Abstract

Sweet sorghum (Sorghum bicolor (L.) Moench) has been recognized globally as a potential biofuel crop for ethanol production. Sweet sorghum is a drought-tolerant crop that is widely adapted to different environmental growing conditions. The aim of this study was to determine the water use efficiency (utilisable yield per unit amount of water used) of drip-irrigated sweet sorghum (variety Sugargraze) under two different climatic conditions in South Africa. The sweet sorghum trials were conducted at Ukulinga research farm (University of KwaZulu-Natal, Pietermaritzburg) and Hatfield experimental farm (University of Pretoria, Pretoria), South Africa. Field trials were conducted in two successive seasons, viz., 2010/11 and 2011/12. Seasonal water use was estimated using eddy covariance and surface renewal methods. Fresh and dry aboveground biomass yield, stalk yield and stalk Brix % were measured at final harvest. Theoretical ethanol yield was calculated from fresh stalk yield and Brix %. Water use for the two growing seasons was 415 mm at Ukulinga and 398 mm at Hatfield. The ethanol water use efficiency (WUE) values for the sweet sorghum at Ukulinga were 0.27 and 0.60 L∙m-3 for 2010/11 and 2011/12 growing seasons, respectively. The ethanol WUE estimate of the sweet sorghum at Hatfield was 0.53 L∙m-3 for the 2010/11 season and 0.70 L∙m-3 for the 2011/12 growing season. WUE estimates of the sweet sorghum crop were higher for Hatfield compared to Ukulinga research farm. The results from this study showed that the WUE of sweet sorghum was sensitive to plant density. The WUE values confirm that sweet sorghum has high WUE under different climatic conditions.

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Published

2016-01-27

Issue

Vol. 42 No. 1 January (2016): Water SA

Section

Research paper

License

Copyright (c) 2022 MG Mengistu, JM Steyn, RP Kunz, I Doidge, HB Hlophe, CS Everson, GPW Jewitt, AD Clulow

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This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

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How to Cite

MG Mengistu (2016) “A preliminary investigation of the water use efficiency of sweet sorghum for biofuel in South Africa”, Water SA, 42(1 January). doi:10.4314/wsa.v42i1.15.