Michael Walsh - Plant Health Summit

Harvest weed seed control

Michael Walsh

Harvest weed seed control Developed in response to

herbicide resistance Because of potential to target

weed seeds

Target seed production at harvest

Weed species Retained seed* (%)

Lolium rigidum 88

Raphanus raphanistrum 99

Bromus spp. 73

Avena spp. 85

* Seed above harvester cutting height (15cm)

Weed seed retention during wheat crop harvest

Time post wheat crop maturity (d)0 7 14 21 28

Seed

rete

ntio

n (%

)

0

20

40

60

80

100

Lolium rigidumBromus spp.Raphanus raphanistrum Avena spp.

Weed seeds exit in chaff fraction

Lot feeding Autumn burning

Chaff carts

Up to 85% of annual ryegrass and wild radish seed removed

Grazing

Chaff collection Lance Turner

Developed conveyor belt chaff transfer system - Easy attachment

-  Shorter burning times

Estimated 200 new chaff carts in WA since 2013

Residue Baling Shields family, Wongan Hills, WA

Glenvar Bale Direct System Up to 95% of annual ryegrass seed removed in baled

harvest residues Financial opportunity where residue is a problem and

there is a market for straw

Chaff lining -  Confine chaff on a tramline or in a row

-  Hostile environment for weed seeds

-  Leave undisturbed

Annual ryegrass seed survival Seed packets placed under chaff at harvest then retrieved prior to seeding

Survival

(%) Chaff (t/

ha)

Canola 2 31

Wheat 74 19

Barley 3 18

Survival

(%) Chaff (t/

ha)

Canola 6.5 14

Wheat 36 16

Chaff on tramline Chaff in narrow row

Chaff processing

Cagemill results >90% kill of annual ryegrass seed

No effect of chaff type

0

20

40

60

80

100

700 900 1100 1300

Seed

sur

viva

l (%

)

Cagemill speed (rpm)

Harrington seed destructor

Harrington seed destructor

Comparison of HWSC systems Narrow Windrow Burning, Chaff Carts and HSD

Replicated treatments at 25 sites

Lolium emergence in autumn

Treatment  Reduc-on  in  Lolium  emergence    

(%)  HSD   57  Chaff  cart   56  

Narrow  windrow  burn   57  

LSD  (P=0.05)   9  

Weed species   SE  

Annual ryegrass   93   0.7  Wild radish   99.8   0.2  Wild oats   99.9   0.1  

Brome grass   99   0.2  

Efficacy of iHSD

Prototype Integrated Mill

Prototype Integrated Mill

0

5

10

15

20

25

30

35

40

45

50

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Annu

al  ryegrass  (plann

ts/m

2 )Focus  paddocks   -­‐ surviving   ryegrass   in  spring

Plus  HWSC

Minus  HWSC

The value of HWSC

0

500

1000

1500

2000

2500

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Ryegrass  se

ed  pr

oductio

n  (seed/m

2 )Focus  paddocks  -­‐ Estimated  ryegrass  seed  set

Plus  HWSC

Minus  HWSC

The value of HWSC

HWSC is an accepted practice Adopted by approx. 40% Australian crop producers

Cumulative  adoption  curves  for  narrow  windrow  burning  by  agro-­‐ecological  zones    100  

 90  

 80  

 70  

60    

50    

40    

30    

20    

10    

0  2000   2002   2004   2006   2008   2010   2012  

NSW  Central  NSWNW/Qld  SW  Qld  Central  SA  Vic  Bordertown  -­‐  Wimmera  Vichigh  rainfall  and  Tas  grain  WA  Eastern  WA  Northern  

NSWNE/Qld  SE  NSWVic  Slopes  SA  Midnorth  -­‐  Lower  Yorke  Eyre  SA  Vic  Mallee  WA  Central  WA  Sandplain  -­‐  Mallee  

%  of  gr

owers  

Low weed densities are insurance against resistance

evolution

Thank you