What do you do when you feed into a computer soil carbon data from more than 20,000 samples from more than 4,500 locations and a range of land uses and management regimes and what comes out is... gibberish? No meaningful pattern? This happened with SCaRP. It failed to detect statistical difference in soil carbon rates between land management practices. (See 'No difference was detected...' below)
What would you conclude? Taken literally - as some experts did - means you would be accepting the absurd proposition that farmers can treat soil anyway they want, it won't change soil carbon levels. If so, where did 70% of the nation's Soil Organic Matter go since 1770? Aboriginal Agriculture? Or over-grazing, over-ploughing by farmers who learned to farm in Europe?
Would it be safer to ask the question: "Did we ask the wrong question?" Instead of asking which land management regime builds soil C faster and further, they could ask: "Which farmer has built soil C faster and further, and how did they do it?"
This is now our focus.
‘No difference was detected …’
between high and
low P fertiliser inputs to pastures.
Central tablelands NSW
between set stocking and rotational grazing (Central tablelands NSW
between pasture cropping and permanent pasture. Central slopes NSW
|
between native pasture (tropical pasture , tillage minimum
tillage. Northern slope and plains NSW
|
between native grass , lucerne , Rhoades grass and Premier digit
. Northern slope and plains NSW
|
between cropping with organic fertilisers and chemical fertilisers. Northern tablelands NSW
between rotational grazing
and set stocking pastures. Northern tablelands NSW
|
between tillage, stubble and fertiliser treatments. Hermitage
research trial Qld
|
between conventional tillage and no-tillage systems. Goodger
research trial Qld
between conventional tillage and no-tillage systems. Biloela
research trial Qld
|
between stubble retention and stubble burning at MacKay and
Bundaberg trials. Sugarcane Qld
|
between grazing pressure treatments on SOC stock, Wambiana grazing
trial Qld Rangelands
between cell, rotational or continuous grazing management practices
, Qld
between phosphorus application or stocking rates. Hamilton Vic
|
between continuous grazing, optimised deferred grazing, and timed
grazing. Ararat Vic
|
between applied stubble management and tillage treatments Horsham
Vic
|
between annual pasture and
perennial pasture . Esperance WA
|
between stubble retained and
stubble burnt . Merridin WA
|
Analysis of results of the $24m Soil Carbon Research Program has led
some to the conclusion that management cannot affect carbon levels in
soils.
The Case For Soil Carbon
The Case For Soil Carbon
There is no rule book for different land management practices. What one farmer calls ‘rotational grazing’ another
calls ‘cell grazing’ and another ‘time-controlled grazing’ or ‘grazing
management’. Or ‘high intensity/short duration grazing’. And every farmer adapts techniques
according to their skills, knowledge, and experience.
None of these variables were considered in the study. But Dr Jeff Baldock, in his report on SCaRP,
seems to conclude that the manager rather than the management system that makes
the difference: “Consider the situation where the water use efficiency of
continuous cropping systems ranges from 60% to 90% across a region due to
landowner abilities and preferences. Under these conditions, differences in the
input of carbon to a soil will result and soil carbon values will vary even
under similar soil, climate and topographic conditions.”
It's the farmer, not the farm management system. It's the knowledge, expertise and experience of the manager. This is where the next wave of research should be focussed.
It's the farmer, not the farm management system. It's the knowledge, expertise and experience of the manager. This is where the next wave of research should be focussed.
Finally,
when a farmer practices Carbon Farming, they don’t do it one activity at a
time. They might have six or more soil-carbon-boosting practices active on the
same paddock over a reporting period of 5 years. Yet studies will single out
one of them and try to measure the results. This problem arises because of the choice made between two approaches to measuring sequestration: Activity-based (isolating each practice for separate analysis) and Outcome-based (simply measuring the change in soil carbon levels for a defined piece of land). Insurmountable complexity and cost attend the one the IPCC chose where Common Sense would recommend the other.
