Research Findings - Pasture Production and Dairy Richard Eckard, - - PowerPoint PPT Presentation

Research Findings - Pasture Production and Dairy

Richard Eckard, Brendan Cullen, Matt Bell, Nat Browne - UoM Richard Rawnsley, Karen Christie - TIA

Toolkit

• Whole Farm Systems models

– DairyMod, SGS, GrassGro, APSIM

• DSS tools

– UDDER, DairyPredict, MIDAS, COST

• GHG Accounting models

– Dairy, Beef, Sheep, Crop GAF – DGAS, FarmGas

• Downscaled climate data

– Simple, CFT and CCS

• People

– Workshops – Model training

Warmer and drier future climates projected for southern Australia (A1FI)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pasture growth rate (kg DM/ha.day)

20 40 60 80 100 Baseline 2030 climate 2070 climate

Will change the seasonal pattern of pasture growth With higher pasture growth rates in winter and early spring but a contraction of the spring growing season

Cullen et al (2009) Crop & Pasture Science, 60, 933–942.

Warmer Drier 1971-2000 2070 2050 2030

Resilience surfaces of pastures

Cullen et al. (2012). Crop and Pasture Science, 63:77-86.

Warmer Drier 1971-2000 2070 2050 2030

Resilience surfaces of pastures

Cullen et al. (2012). Crop and Pasture Science, 63:77-86.

Warmer Drier 1971-2000 2070 2050 2030

Resilience surfaces of pastures

Cullen et al. (2012). Crop and Pasture Science, 63:77-86.

Resilience surfaces of pastures

• Total annual pasture production in southern

Australia is generally resilient to climate changes of +1⁰C with 10% less rainfall

– but further changes are likely to reduce annual pasture growth

• Responses differ at locations

– Therefore adaptations will differ

Warmer Drie r

Cullen et al. (2012). Crop and Pasture Science, 63:77-86.

Should we consider Kikuyu in future?

• Compare to ryegrass, Kikuyu has

– Higher heat tolerance – Higher water use efficiency, deeper roots

2 4 6 8 10 12 14 1 2 3

Mean annual pasture production (t DM/ha) Warming (°C) Perennial ryegrass/ subclover Kikuyu/ Subclover

Bell et al. (2011) Modsim

Should we consider Kikuyu in future?

• Substantial warming is

still required before C4 grasses will be more productive than the current C3 species

50 100 150 200 250 300 350 1 2

ME yield (GJ/ha) Elliott

50 100 150 200 250 300 350 1 2

ME yield (GJ/ha) Warming (oC) Hamilton

 P ryegrass  Kikuyu

Bell et al. (2011) Modsim

Inter-annual and seasonal variability

• Declining trend in pasture production
• Variability currently high, but not outside the

historical range

Bell et al. (2011) 2011 GSSA conference

5 Sites across Victoria and Tasmania

Inter-annual and seasonal variability

• 5 Sites across Victoria and Tasmania
• Greater frequency of short spring

1 2 3 4 5 6 7 8 Frequency (yrs out of 10) Short Long

Hamilton

Bell et al. (2011) 2011 GSSA conference

Future change in autumn breaks and length of spring in NW Tasmania

0% 10% 20% 30% 40% 50% 60% 1971-2000 2001-2030 2031-2060 2061-2090 Percentage

Early Autumn Breaks

Christie et al. (2012) ASA conference

0% 10% 20% 30% 40% 50% 60% 1971-2000 2001-2030 2031-2060 2061-2090

Long Spring

Echam GFDL20 GFDL21 Miroc Mk35 Ukhad Mean

Breeding future pasture species

• Deeper rooting and

heat traits will be important adaptations for pasture species in future warmer and drier climates

Baseline 2070 climate 2070 - deep roots 2070 - heat tol. 2070 - deep roots & heat tol. Pasture production (t DM/ha)

6 8 10 12 14 16 18

Cullen (2009) Crop and Pasture Science 60, 933–942

Plant traits for future climates – using surrogates

Perennial Ryegrass

• Susceptible to lower rainfall
• Likely reduced persistence

Tall fescue

• Advantage of
• Deeper roots
• Heat tolerance

Phalaris

• More resilient to lower rainfall
• Summer dormancy aids

persistence

Kikuyu

• More summer growth
• More production if
• Warmer and little rainfall

change

Cullen at al (2012) Climate Change

DGAS Calculator

Dairy greenhouse gas emissions

• GHG emissions on >100 dairy farms using DGAS

– ~1 kg CO2e/kg milk – Milk production/cow is key driver of GHG emissions intensity

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 10 20 30 40 50 60 Milk GHG emissions intensity (kg CO2e/kg milk)

60 Tasmanian farms

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 5 10 15 20 25 30 35 40 Milk GHG emissions intensity (kg CO2e/kg milk)

41 Australian farms Christie et al. (2011) Animal Feed Science and Technology 166-167: 653-662

GHG emissions in future climates

• N2O could

increase in southern Australia

1971-2000 2030 High 2070 Med 2070 High N2O emissions (kg N/ha.year) 2 4 6 8 10

Kyabram Terang Ellinbank Elliott

Eckard & Cullen (2011) Animal Feed Science and Technology 166-167: 736-748

Carbon Offsets Scenarios Tool (COST)

• Mitigation options as potential CFI offsets
• Financial viability of offset strategy
• CFI income, implementation cost, productivity gain,

total farm benefit

Implications

• May not need to change species by 2050

– BUT

• Seasonal distribution of growth will require adaptation
• Plant breeding should start now

– Temperature tolerance & deeper roots in C3 grasses – Higher quality in C4 grasses

• Modelling recovery from extreme events

– Current tools inadequate

• On-farm N2O may increase in future climates

– Mitigation modelling important – Strategies should also improve N efficiency