Organic waste from sugar mills as a potential soil ameliorant to minimise herbicide runoff to the Great Barrier Reef

Anil Duhan; Danielle P Oliver; Mehran Rezaei Rashti; Jun Du; Rai S Kookana

doi:10.1016/j.scitotenv.2020.136640

Organic waste from sugar mills as a potential soil ameliorant to minimise herbicide runoff to the Great Barrier Reef

Sci Total Environ. 2020 Apr 15:713:136640. doi: 10.1016/j.scitotenv.2020.136640. Epub 2020 Jan 13.

Authors

Anil Duhan¹, Danielle P Oliver², Mehran Rezaei Rashti³, Jun Du⁴, Rai S Kookana⁵

Affiliations

¹ CSIRO Land and Water, Locked Bag No. 2, Glen Osmond, SA 5064, Australia; CCS Haryana Agricultural University, Hisar 125004, India.
² CSIRO Land and Water, Locked Bag No. 2, Glen Osmond, SA 5064, Australia. Electronic address: Danni.Oliver@csiro.au.
³ School of Environment and Science, Griffith University, Nathan, Queensland 4111, Australia. Electronic address: m.rezaeirashti@griffith.edu.au.
⁴ CSIRO Land and Water, Locked Bag No. 2, Glen Osmond, SA 5064, Australia. Electronic address: Jun.Du@csiro.au.
⁵ CSIRO Land and Water, Locked Bag No. 2, Glen Osmond, SA 5064, Australia; School of Agriculture, Food and Water, University of Adelaide, Waite Campus, Glen Osmond 5064, Australia. Electronic address: Rai.Kookana@csiro.au.

PMID: 32019023
DOI: 10.1016/j.scitotenv.2020.136640

Abstract

We studied sorption potential for a range of herbicides using eleven waste materials (mill muds) containing organic matter (47.6 to 65.1%) produced by sugar mills and applied as soil conditioners by farmers. Sorption/desorption behaviour of five herbicides commonly used in sugarcane production (imazapic, atrazine, hexazinone, diuron and metribuzin) was studied on these mill muds, as is and after adding these to three soils at different rates (5-25%, dry weight basis). All mill muds had significant sorption capacity, especially for diuron, atrazine and metribuzin which was 6 to 26 times higher than the soil with 3.5% organic carbon (OC). Generally, sorption of the five herbicides assessed in all mill muds followed the order diuron > atrazine = metribuzin > hexazinone = imazapic. Eight out of 11 mill muds had similar sorption capacity for any given herbicides. Amending soils with selected mill muds significantly enhanced their sorption efficiency, depending on the rate of application especially in soil with low OC. Generally, application of mill muds at 5% w/w or 40 tons/ha increased sorption of studied herbicides by 2 to 10 folds. Soil amendment with mill muds also reduced the rate and extent of desorption of herbicides- especially mobile herbicides like metribuzin. Nearly 79% release of metribuzin was observed after three desorption steps in amended soil (at 5% w/w), whereas in unamended soil, 100% of metribuzin was released during first desorption step. The study demonstrates that wastes produced by sugar mills may have recycling use in enhancing the retention of mobile herbicides in soils with low OC content.

Keywords: Desorption; Herbicides; LC-QTOF; Mill mud; Sorbent; Sorption.