Do livestock reduce crop yields in conservation farming systems?James Hunt, Tony Swan, John Kirkegaard, Paul Breust, Mark Peoples

Southern Australian mixed farming systems

• Sheep & wheat• Sheep graze crop residues, spilt grain and vegetative crops• Legume based pastures provide N and disease break for crops• Will the full benefits of no-till and controlled traffic ever be

realised whilst sheep are trampling soil and removing cover?• Very little contemporary evidence (Bell et al. 2011 Soil & Tillage

Research 113)• First two years of GRDC project designed to test;

What impacts do sheep grazing on crops and stubbles

have on soil structure, water dynamics and crop yield?

Livestock & conservation farming

WUE & canopy management - Soil2Grain SW WA July 2010

Project structure

• Add photo of research committeeCSIRO

CSIROFarmerFarmer

FarmerFarmerFarmlink

Farmlink Consultant Consultant

“Collective Inquiry”

Livestock & conservation farming

Research site – Temora, southern NSW

• Peter, Lynne and Jason Coleman’s farm (6 km south of Temora)

• Annual rainfall ~ 520 mm temperate pattern• Red Chromosol with flat topography• Lucerne pasture of 4 years in 2008• No-till (300 mm row spacing), knife-points and press wheels• Controlled traffic

Livestock & conservation farmingSpraying on tramlines (CT)

Livestock & conservation farming

Effects of stock on soil & crop

• Treatments1. Nil graze, stubble retention

2. Nil graze, stubble burn

3. Stubble graze, stubble retention

4. Stubble graze, stubble burn

5. Winter graze, stubble graze, stubble retention

6. Winter graze, stubble graze, stubble burn

• RotationPhase 1: Lucerne 08 - wheat 09 - canola 10 - wheat 11

Phase 2: Lucerne 09 - wheat 10 - canola 11 - wheat 12

Livestock & conservation farming

Effects of stock on soil and crop

wheat 09 – summer fallow - canola 10 – summer fallow – wheat 11

• Treatments summer 2009/20101. Nil graze (5.4 t/ha stubble)

2. Stubble graze (0.8 t/ha stubble)

3. Winter & stubble graze (0.8 t/ha stubble)

0.8 t/ha5.4 t/ha

wheat 09 – summer fallow - canola 10 – summer fallow – wheat 11

Soil water accumulation summer 2009/2010

• 310 mm of summer rain• 43 mm late Nov/early Dec• 48 mm at Christmas

• 18 mm early Feb• 104 mm mid Feb• 82 mm early Mar

Livestock & conservation farming

Plant available water 10-180 cm (mm)

Treatment 16 Dec 09 13 Jan 10 23 Feb 10 16 Mar 10

Nil graze 13 14 105 155

Stubble graze 14 14 77 110

Stubble & winter graze 15 16 66 99

LSD (P=0.05) NS NS 13 19

wheat 09 – summer fallow - canola 10 – summer fallow – wheat 11

Livestock & conservation farming

Soil water 0-20 cm – no effect of stubble over summer

0

10

20

30

40

50

60

26-Nov 16-Dec 5-Jan 25-Jan 14-Feb 6-Mar 26-Mar

Date

Pla

nt

avai

lab

le w

ater

0-2

0 cm

(m

m)

Graze 0.8 t/ha stubble

Nil graze 5.4 t/ha stubble

43mm

43 mm

18 mm

102 mm

82mm

Livestock & conservation farming

Soil water 16 March 2010

0

20

40

60

80

100

120

140

160

180

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40

Soil water (mm/mm)D

epth

(cm

)

Drained Upper Limit (mm/mm)

Soil water – Nil grazedSoil water - Grazed

Stubble improvedwater infiltration

Livestock & conservation farming

Infiltrometer measurements March and April 2010

Treatment in 2009 Steady-state infiltration rate

(mm/h)

Wheat stubble - Nil graze 36a

Wheat stubble - Stubble graze 20b

Wheat stubble - Winter & stubble graze 16b

Canola (little stubble cover) - Nil graze 11b

LSD (P=0.05) 11

wheat 09 – summer fallow - canola 10 – summer fallow – wheat 11

Livestock & conservation farming

wheat 09 – summer fallow - canola 10 – summer fallow – wheat 11

• Canola Tawriffic TT sown over all treatments 15 April 2010• Winter grazed prior to bud emergence• 426 mm GSR

• No significant effect of grazing on canola grain yield• Differences in PAW from summer 09/10 still present

Livestock & conservation farming

Canola grain yield 2010

Treatment Canola grain yield (t/ha)

PAW at canola maturity (mm)

Nil graze (5.4 t/ha wheat stubble)

4.1 116

Stubble graze (0.8 t/ha wheat stubble)

4.2 86

Stubble & winter graze (0.8 t/ha wheat stubble)

4.0 78

P-valueLSD (P=0.05)

0.62NS

0.0125

Livestock & conservation farming

Effects of stock on soil and crop

• Treatments summer 2010/20111. Nil graze (8 t/ha stubble)

2. Stubble graze (4 t/ha stubble)

3. Winter & stubble graze (4 t/ha stubble)

wheat 09 – summer fallow - canola 10 – summer fallow – wheat 11

Livestock & conservation farming

Soil water 0-20 cm - summer fallow 2010-2011

Livestock & conservation farming

Plant available water & N at sowing 2011

Grazing treatmentMineral N (kg/ha)

15 April 2011PAW (mm) 15

April 2011

Nil graze (8 t/ha stubble) 93a 201a

Stubble graze (4 t/ha stubble) 126ab 183b

Winter and stubble graze (4 t/ha stubble) 199b 187b

P-value 0.001 0.011

LSD(P=0.05) 49 11

CV (%) 28 5.6

wheat 09 – summer fallow - canola 10 – summer fallow – wheat 11

Grazing treatmentCanopy temperature

(°C)

Nil graze (8 t/ha stubble) 21.8a

Stubble graze (4 t/ha stubble) 22.6b

Winter and stubble graze (4 t/ha stubble) 23.0b

P-value 0.005LSD(P=0.05) 0.7

CV (%) 2.8

wheat 09 – summer fallow - canola 10 – summer fallow – wheat 11

Livestock & conservation farming

Acknowledgements

• CSIRO & FarmLink Research team – Tony Swan, Paul Breust, James Hunt, John Kirkegaard, Mark Peoples

• FarmLink WUE steering committee - Jason Coleman, Peter Coleman, Greg Condon (Grassroots Agronomy), Chris Duff (Delta Agribusiness), Derek Ingold, James Ingrey, Geoffrey Lane, John Pattison, Jamie Pursehouse (Landmark – Ariah Park), Michael Sinclair, Rob Taylor, Craig Warren (Landmark - Temora)

• NSW I&I – Col McMaster, Neil Fettell & Ian Menz,• Lindsay Bell – CSIRO Toowoomba• Seed provided by Hart Bros. Seeds & Pioneer• Bayer CropScience - Sakura

Thank you

CSIRO Plant IndustryJames HuntResearch Scientist

Phone: 0428 636 391Email: james.hunt@csiro.auWeb: www.pi.csiro.au/

Contact UsPhone: 1300 363 400 or +61 3 9545 2176Email: Enquiries@csiro.au Web: www.csiro.au