the impact of trash management and tillage on soybean productivity in sugar based farming systems....

Department of Employment, Economic Development and Innovation

The impact of trash management and tillage on soybean productivity in sugar based farming

systems

Neil Halpin – DEEDI Bundaberg

Dr Mike Bell – QAAFI Kingaroy

William Rehbein and Sherree Short– DEEDI Bundaberg

2© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011

Australian Sugar Industry• Worth $2 Billion/Yr – (2nd largest export crop behind wheat)• 350 – 400 000 ha• 32 – 35 Million tonne of Cane• 4.5 – 5 Million tonne of Sugar• 4000 Cane growing Businesses with 6000 growers• 24 sugar mills• Employs 40 000 people directly and indirectly


Southern Canelands


Southern Canelands• Includes the Bundaberg, Childers and Maryborough growing regions

Bundaberg Childers Maryborough

Area of cane (ha) 19 000 13 000 10 000

Productivity (tCane/ha)

81 84 64


The Sugar Yield Decline Joint Venture


A more sustainable sugarcane farming system has 4 key components

Grain legume rotations

Reduced Tillage

Controlled traffic

Trash retention


Why are grain legume rotations important?


50

70

90

110

130

150

Plant R1 R2 R3

Can

e yi

eld

(t/h

a)

Cane (Ploughout/replant) Grain legume crop (12 M)

Yields average at least 20% greater after grain legumes over whole crop cycle


Grain legumes greatly improved the soil biology (Bundaberg rotation trial)

No. nematodes/200 ml soil

After cane After legume

Lesion 49 14

Reniform 309 23

Stubby root 9 1

Spiral 199 28

TOTAL 566 66

Bacterial feeders 1905 6997

Fungal feeders 1258 1958

TOTAL 3163 8955

Beneficial/Pests 6:1 136:1


Aggressive tillage destroys soil structure and costs time and money

Tillage Treatment Effects on Inputs

0

50

100

150

200

250

Conventional Tillage Zonal Min Tillage Stool Sprayout

Fu

el

(L/h

a)

Po

we

r (k

W/h

a)

0

5

10

15

20

25

Ho

urs

/ h

a

Fuel kW Hours

A reduction in tillage offers an opportunity to save money and reduce impact on soil structure


Cane grown on 1.5m rows.

Harvester on 1.8m centres

Why do we need to control traffic?


Why retain trash?

• Weed suppression• Water conservation• Improved soil carbon status• Improved rainfall capture

Cane trash management effect on soil labile carbon

0

0.5

1

1.5

2

2.5

1

Lab

ile

carb

on

(m

g/k

g)

Burnt GCTB


Benefits of trash continued

Effect of organic matter retention on nematode supression - RKN

0

50000

100000

150000

200000

250000

None GCTB

Soil Cover

RK

N/2

00m

L s

oil

OM Cane OM Cane and Soy OM Nil


This is all really great stuff! Are producers adopting these practices??

• Some components like legume rotations are well adopted• Controlled traffic is gradually being accepted• There has been some reduction in tillage BUT – Dealing with a large

trash blanket and a relatively short time frame between crops is problematic


Typically there is 7 -12 t/ha of cane trash post harvest of the final ratoon

How do you handle this amount of trash and cycle between cane harvest and legume planting?

Trash yield relative to cane yield

6.0

7.0

8.0

9.0

10.0

11.0

12.0

13.0

40 60 80 100 120 140

Cane Harvested (T/ha)

Tra

sh b

lan

ket

(T/h

a)


Trash Management option 1: Retain GCTB


2 passes with Rotary hoe

Then a deep ripping

A final rotary hoe operation will occur pre-plant to provide a good seed-bed.

Hardly minimum tillage system!


Trash management option 2: Bale the trash


Baling trash allows for a reduction in tillage

• However aggressive tillage equipment is still utilized• Exporting nutrients and organic matter out of the farming system

Nutrients in Cane Trash (Relative to cane yield)

0

20

40

60

80

100

120

0 20 40 60 80 100 120 140

Cane yield

Kg

of

nu

trie

nts

/ h

a

Nitrogen Phosphorous Potassium Calcium Magnesium Sulphur


Trash management option 3: Burn trash

Most of the nutrients other than N are retained yet complete loss on organic matter

Allows a reduction in tillage compared to the full trash model


How we manage cane trash and tillage will have a large impact on the farming system

• Remember the New Farming System has Trash retention, reduced tillage, legume rotations!

• Removal of trash and use of aggressive tillage equipment will REDUCE the potential soil health benefits that the New Farming System can deliver


Trash management by tillage trial• Determine the impact of differing trash and tillage management

techniques on soybean productivity


Trash Management Options

by

Full Tillage Zonal – “Strip-Till” Direct Drill

Full TrashSome Removed

Burnt

Tillage Options


Trash management options have already been explained


Tillage treatments• Conventional Tillage = 3 rotary hoe operations and 1 deep ripping• Strip Till = Coulter rip on soybean plant line and 2 passes of fluted

coulter• Direct Drill = No Tillage

Factorial trial replicated 3 times in plots 5 cane rows wide by 25m length

The trial was fully irrigated via travelling irrigator


Treatment Trash Management Tillage

1 Full Trash – GCTB Conventional Tillage

2 Full Trash - GCTB Strip Till

3 Full Trash - GCTB Direct Drill

4 Baled - Some removed Conventional Tillage

5 Baled - Some removed Strip Till

6 Baled - Some removed Direct Drill

7 Burnt Conventional Tillage

8 Burnt Strip Till

9 Burnt Direct Drill


Strip-till equipment to alleviate sub-soil constraints yet leave trash on the surface

Cane controlled by “double-knock” herbicide application technology


Soybean planter

Large coulter to cut through trash

Double Disc openers


Soybean planter

Vacuum plate seed meter

Twin inclined press-wheels

Innoculant water injected peat


Site planted – 24th November 2009


Trash management had no effect on crop establishment

Trash managment effect on soybean establishment

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

1

Pla

nts

/ha

GCTB Baled Burnt


Tillage had a significant effect on soybean establishment

Tillage effect on soybean establishment

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

1

Pla

nts

/ha

Conventional Strip-Till Direct Drill

a ba


Flowering biomass 42 (DAS)

Trash management effect on biomass at flowering

0

0.5

1

1.5

2

1

Dry

mat

ter

pro

du

ctio

n (

t/h

a)

GCTB Baled Burnt

Trash management didn’t significantly effect productivity at flowering (p=0.066)


Biomass production at flowering 42 (DAS)



Tillage effect on biomass production 42 (DAS)

Tillage effect on biomass production - flowering

0

0.5

1

1.5

2

2.5

1

Dry

ma

tte

r p

rod

uc

tio

n (

t/h

a)


a a b


Trash management effect on maximum biomass – 113 (DAS)

Trash management effect on maximum biomass

0

2

4

6

8

10

12

1Dry

ma

tte

r p

rod

uc

tio

n (

t/h

a)

GCTB Baled Burnt


Tillage effect on maximum biomass production – 113 (DAS)

Tillage effect on maximum biomass production

0

2

4

6

8

10

12

1Dry

mat

ter

pro

du

ctio

n (

t/h

a)



Grain Yield

n.s. effects

Cane trash management effect on soybean grain yield

00.5

11.5

22.5

33.5

44.5

5

1

Gra

in y

ield

(t/

ha

)

GCTB Baled Burnt


Grain Yield

Tillage effect on soybean yield

0

1

2

3

4

5

Gra

in (

t/h

a)

Full Tillage Strip Till Direct Drill


Large effect of tillage on plant heightTillage effect on soybean height

0

20

40

60

80

Pla

nt h

eig

ht a

t har

vest

(cm

)


a a bTillage effect on lowest pod height

0

2

4

6

8

10

Lo

we

st

po

d h

eig

ht

at

ha

rve

st

(cm

)


a a b


Tillage effect on plant height

Conventional – Full TillageStrip - tillDirect Drill


Pods set close to the ground are difficult to recover and reduce yield


Strip Tillage system warrants commercial evaluation • Strip tillage overcame the significant constraints associated with a

reduced tillage system by:– Improved crop establishment (compared to direct drill)– Increased early growth (compared to direct drill)– Comparable crop height and height of lowest pod to

conventional• Strip Tillage

– Addresses sub-soil constraints– Maintains surface cover – erosion, soil carbon, weed &

nematode suppression– Facilitates a reduced and less aggressive tillage regime


Reduced tillage on a controlled traffic platform

• Has the potential to deliver significant benefits to the Australian sugar industry


Where to from here??• The site has now been planted to cane with the tillage treatments

maintained.• This trial has been repeated with peanuts rather than soys• Commercial evaluation needs to take place


Acknowledge

• Bundaberg Sugar for access to site• Trial activity was funded by GRDC/SRDC and part of DAQ00129

Improving the integration of legumes in grain and sugarcane farming system in southern Queensland.

the impact of trash management and tillage on soybean productivity in sugar based farming systems....

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