Controlled traffic/permanent bed farming reduces greenhouse gas emissions by using permanent traffic lanes that minimize soil compaction compared to conventional tillage. A pilot study found nitrous oxide emissions were 5-7 times higher in permanent traffic lanes compared to non-wheeled permanent beds. As controlled traffic farming only wheels 10-20% of the area while conventional farming wheels 50% or more, controlled traffic farming is expected to reduce soil emissions by over 50%. Improved soil health and water use efficiency with controlled traffic farming may also increase carbon input into soils. Further research is still needed across different environments.
Barangay Council for the Protection of Children (BCPC) Orientation.pptx
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Controlled traffic/permanent bed farming reduces GHG emissions. Jeff Tullberg
1. Controlled traffic/permanent bed
farming reduces GHG emissions.
Jeff Tullberg , Jack McHugh, Boorzoo Ghareel Khabbaz,
University of Southern Queensland, Toowoomba and CTF Solutions, Brisbane.
Clemens Scheer, Peter Grace
Queensland University of Technology, Brisbane.
2. Australian controlled
traffic (no-till) farming
Harvesting, Seeding, Spraying,
From same permanent traffic lanes
3. China Controlled
Traffic Research
Harvesting, Seeding, Spraying,
From same permanent traffic lanes
4. Controlled Traffic Farming (CTF)
• Permanent traffic lanes for all heavy wheels.
Permanent no-till crop beds.
• Layouts designed for drainage and logistics.
Timeliness, precision, better soil and agronomy*
*opportunity crops, optimised inputs
Many characteristic shared with
– Permanent Raised Bed (PRB) in Mexico and Asia
– Permanent bed, reduced-till intensive cropping.
Impact?
5. TComparison of wheeled and non-wheeled soil
Parameter Units Australian Vertosol China, Loess
Wheeled Non-wheeled Wheeled Non-wheeled
Wheel Load t/axle 4-5 1-2
Rainfall ( 5year mean) mm/yr 907 (incl. irrigation) 558
Runoff ( 5year mean) mm/yr 193 112L 32 18W
Infiltration (80mm/h, 1h) mm/h 27 97L 12 41W
Available Top mm 29 47M 27 30W
water 300mm
Bulk density 1.36 1.28M 1.51 1.59W
Earthworms/m2 # 40 108
Fuel use, seeding l/ha 5.6 3.0T / /
Grain yield( 5year mean) t/ha 3.70 4.05T 3.05 3.25W
L Li et (2007); W Wang et al(2009): T Tullberg et al(2007); M McHugh et al(2009)
Why?
6. Annual Tractor Wheel Impact in Zero Till
Black = Soil Solids, White = Air or Water (from D.McGarry )
24 cm
4- Years CTF Annually Wheeled
Non-Wheeled (5t Tractor)
.
Greenhouse Impact?
7. Greenhouse gas emissions (not Carbon)
• Inputs
• Fuel, Machinery
• Herbicides
• Fertilisers
} Easily Quantified
For Known Systems
Energy
• Outputs
• Nitrous oxide & methane
• Nitrate in runoff and drainage
• Nitrate in eroded soil } Highly Variable,
Less Well-Understood
Wasted Energy
In practise:
Greenhouse Impact = Economic Impact
8. Soil Emissions – Nitrous Oxide, NO3 (+ Methane)
Literature: N loss and emissions associated with waterlogging
NO3emissions occur when: Water- filled porosity <75%, >65%.,
Nitrate +C present in surface 10 cm.
Management Impact ?
Till v. no-till: less NO3 emissions in well-drained soils. (Rochette 2009)
more NO3 emissions in poorly drained soils.
(measurements rarely taken in wheel tracks)
Wheel effect: wheeled soil emissions 5 x non wheeled (Russer 1998)
(potato fields) wheeled soil emissions 5 x non wheeled (Thomas 2003)
Common thread– wheel effects?
9. Pilot trial, 2010 Wheat seeded + 80kg/ha N
as anhydrous ammomia, interrow
4-year of 3m CTF
heavy vertosol, disk
seeder, tine fertiliser.
3m
Emission Chambers
Permanent
Traffic Lane
(T.Lane)
Permanent Bed
Non-Wheeled
Permanent (P.Bed)
Permanent Bed +
Traffic Lane 1 Pre-seeding Wheeling
(T.Lane) (Rand)
10. Emissions
N2O-N T Lane
400 ug.m-2.h-1 Rand
350 P Bed
300
250
200
150
100
50
0
0 10 20 30 40 50
Days after planting
Wheel Impact:
N2O increased significantly on 3 occasions after rain
CH4 increased significantly on 1 occasion after rain
11. Cumulative Emissions Emissions (6 weeks post-seeding)
kg CO2-e/ha
Source T Lane Rand P Bed
kg kg kg
N2O 324.6 369.5 58.2
CH4 0.33 0.41 -0.43
Total 324.6 369.5 58.2
Ratio 5.57 6.35 1.00
Wheeltrack emissions probably greater by a factor of 5.0 – 7.0
12. Conclusions
1. Pilot trial confirms the literature:
wheel track emissions 5-7 times greater than bed emissions.
2. Permanent traffic lanes in CTF occupy 10– 20% area.
but minimum of 50% area is wheeled in non—CTF.
3. This suggests that CTF should reduce soil emissions by >50%
possibly more with precise, split N application.
plus a substantial impact on input-related emissions.
4. Improved agronomy, soil health and precision also increase WUE
indicating possibility of greater biomass and C input.
Needs investigation in different environments