Adoption of more sustainable establishment systems could provide UK growers with greater resilience against more variable crop prices in the future.
Latest research findings from a long-term Syngenta conservation agriculture and sustainable farming systems initiative show that while crop income across the rotation was marginally lower with reduced tillage establishment, the potential cost savings from low till could result in consistently higher margins, particularly if crop values fall.
The research project compares environmental impact, financial results and agronomy challenges of three establishment systems: conventional (plough-based); min till and low till (direct drilling) – on a field scale, through a whole farm rotation.
It is operating on two contrasting sites in the UK: The Allerton Project’s heavy soils at Loddington Farm in Leicestershire and the light soils of Kent grower, Andy Barr, near Maidstone.
Loddington head of farming, Phil Jarvis, calculates crop values from this year’s harvest across the rotation, including winter wheat, barley, oilseed rape and spring beans, were nearly 5% higher from conventional plough-based establishment, at an average £1,082/hectare at current prices, compared to low till (see Fig 1).
Machinery However, when potential machinery cost savings were factored in, margins from the low till system (£532/ha) were 19% higher than conventional across the rotation, with min till slightly ahead of the plough at £456/ha.
Furthermore, he says that if crop values fell, by an arbitrary 30%, for example, the Loddington light till system would still deliver a margin of £221/ha, compared to £156 for min till and just £126 with conventional plough establishment.
If prices were to rise by 30%, Phil’s calculations indicate plough systems would give better margins than min till, but low till establishment would still perform best.
“The caveat to the better financial performance of reduced tillage is that growers would need to be committed to making the cost savings, by reducing tractors and cultivation equipment on-farm,” he advises.
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Kent grower Andy Barr is a long-term advocate of direct drilling, with more than 90% of the farm cropping established with his Dale drill.
His fields entered into the sustainability initiative threesystem trials had not been ploughed since 2001 and direct drilled for the past decade.
Mr Barr reports that yield maps for the first year of comparative establishment systems indicate both wheat and spring barley yields were similar for all methods, but OSR yields were higher with direct drilling, and spring bean yields higher with ploughing.
He says: “Having direct drilled for many years, we are always very frustrated when we cultivate, with how long it takes and how much more diesel and metal we use.
“Given the similar yields, we are hopefully maximising margins with reduced cultivations, but acknowledge everyone will have different situations and preferences.”
He argues that, compared to plough and cultivation for establishment, it requires more management time and knowledge the more the degree of tillage is reduced, if more variable yields are to be avoided.
“Initial results seem to show we are on the right track on our soils but that perhaps we should be open to some strategic cultivations occasionally if we want to maximise margins in any one year,” he says.
“I am keen to learn whether we can do this without compromising long-term soil and wildlife health.
“In the past we have observed increased worms, beetles and even birds with reduced tillage, but it will be interesting to see if more rigorous scientific approach with NIAB monitoring bears this out.”
He points out his direct drill system does critically rely on glyphosate.
“If that goes, maybe some form of cultivation will inevitably be required, and perhaps these trials can help us find how best to use strategic low disturbance cultivations to boost our yields in some situations, while improving soils and the environment.”
With farming under intense spotlight for greenhouse gas emissions, scientists working on the sustainable farming initiative are now measuring the relative release of carbon dioxide, methane and, potentially more damaging, nitrous oxide, under the cultivation systems.
Mr Jarvis reports challenges with accurate representative measuring of emissions from growing arable crops at very low levels.
However, with the combined gases converted to a CO2 equivalent, initial sample results averaged across the two sites indicated the light till system produced just 50% of emissions of plough establishment (see Fig 2), with min till 14% lower than the plough.
He says: “One interesting observation from our trials is that more nitrous oxide appears to be produced in anaerobic wet conditions.
“That could be further influenced in future by cultivation techniques and climate change events. We will be continuing to assess and evaluate this, with more future measurements in wet conditions
Microbial activity is a key indicator of soil health and for the utilisation of organic nutrients by crops.
Research on the sustainable farming initiative is using porous bags containing different types of tea leaf to assess decomposition rates over a 90-day period as a relative measure of microbial activity under differing establishment regimes.
Initial results have shown a clear trend of greater microbial activity with low till establishment, particularly in fields with spring beans and winter oilseed rape.
There was only limited difference between min till and conventional systems.
As the project continues through the rotation, Phil Jarvis believes the implications between different soil types, cropping and establishment systems on microbial activity can be far better evaluated and understood.
Measurement of soil strength and density at depth is a good indicator for potential plant rooting capability.
It is also an early indication if other actions are required to maintain soil structures, according to Nathan Morris of NIAB TAG.
Results averaged across the Kent site for this season showed that both reduced tillage systems had greater strength near the surface, compared to conventional plough.
However, the point at which soil strength could restrict root growth was reached at 23cm with reduced tillage, compared to 38cm with a plough-based system.
Dr Morris says: “Surface soil strength is beneficial for plant anchorage and avoiding slumping. But deeper rooting is important, particularly for drought resilience and efficient nutrient utilisation”.