Hangs, R.D.

Schoenau, J.J.

Szmigielski, A.M.

English

eCommons@USASK

Bioavailability of metsulfuron and sulfentrazone herbicides in soil as affected by amendment with two contrasting willow biochars

University of Saskatchewan Research Archive

IntroductionThere are multiple environmental and agronomical benefits of biocharaddition to soil. Due to their porous structure, biochars sorb and retain avariety of organic compounds from soil including soil-applied herbicides.The degree of sorption may vary depending on the biochar physical andchemical properties and its application rate [1].ObjectivesThis study investigated the effect of two willow biochars (Salix spp)produced using either fast (at 400°C) or slow (up to 750°C) pyrolysis onthe bioavailability of metsulfuron and sulfentrazone herbicides in soil.Materials and Methods● Five rates (0, 1, 2, 3, 4%; w/w) of each biochar (Table 1) were used,along with varying rates of metsulfuron (0 to 3.2 µg ai kg-1) andsulfentrazone (0 to 200 µg ai kg-1).● To measure herbicide bioactivity in soil with added biochar, a sugarbeet bioassay in WhirlPakTM bags was used [2] (Fig. 1).Anna M. Szmigielski1, Ryan D. Hangs, Jeff J. Schoenau11Dept. of Soil Sci., University of SaskatchewanResults● The fast-pyrolysis biochar had minimal effect (Fig. 2a and 3a), while the slow-pyrolysis biochar decreasedthe bioavailability of both herbicides (Fig. 2b and 3b).● Despite using the same feedstock, the two biochars had different physical and chemical properties (Table 1),of which specific surface area was most contrasting (3.0 and 175 m2 g-1 for fast- and slow-pyrolysis biochar,respectively).Bioavailability of metsulfuron and sulfentrazone herbicides in soil as affected by amendment with two contrasting willow biochars.Fig. 2. Sugar beet root length inhibition in response to metsulfuron in soil amended with increasing concentration of (a) fast-pyrolysis biochar (b) slow-pyrolysis biochar.Fig. 1. Bioassay performed in WhirlPak bags.Table 1. Selected physical and chemical properties of willow biochar produced using slow (at 400°C) or fast (up to 750°C)  pyrolysis.Fig. 3. Sugar beet shoot length inhibition in response to sulfentrazone in soil amended with increasing concentration of (a) fast-pyrolysis biochar (b) slow-pyrolysis biochar.Biochar C%H%O%N%Ash%pH SSA*m2 g-1CECMeq 100g-1Bulk densityg cm-3Fast 70.73.6 12.0 1.4 10.9 9.5 3 26 1.39Slow 81.3 1.9 3.9 0.7 10.6 9.7 175 20 1.16*Specific Surface AreaConclusionsAlthough increased adsorption associated with the high-surface area biochars is useful from the environmentalperspective, further research on how biochars influence the efficacy of soil-active herbicides is needed asbiochar may have negative effect on weed control for years to come.References: [1]Graber et al 2012 Plant Soil 353:95[2] Szmigielski et al 2018 Bull Environ Contam Toxic 100:298Acknowledgements:Financial support from NSERC and Saskatchewan Ministry of Agriculture is gratefully acknowledged(a) (b)(a)Metsulfuron (ppb)0 1 2 3RLI (%)020406080Control1%2%3%4%Metsulfuron (ppb)0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5RLI (%)020406080Control1%2%3%4%Sulfentrazone (ppb)0 50 100 150 200 250SLI (%)020406080Control1%2%3%4%(a) (b)(a)Sulfentrazone (ppb)0 50 100 150 200 250Shoot length inhibition (%)020406080Control1%2%3%4%(b)

https://harvest.usask.ca/bitstream/10388/8718/1/A.%20Szmigielski%20et%20al.%2c%202018.pdf

Bioavailability of metsulfuron and sulfentrazone herbicides in soil as affected by amendment with two contrasting willow biochars

Abstract

Similar works

Full text

Available Versions

eCommons@USASK

University of Saskatchewan Research Archive