As featured in Arable Farming Magazine

Achieving sustainable agricultural systems

by Arable Farming Magazine May issue

As the six-year Assist project comes to an end, the researchers behind the work presented some of the preliminary findings.

A move towards ‘system thinking’ rather than ‘industrial thinking’ may cost more in the short term, but robust systems will start to pay in the long run, Julian Gold, farm manager at the Hendred Estate, Oxfordshire, told the meeting.

He has been taking part in the Assist project for a number of years as part of the experimental farm network.

He recalled how the Assist biodiversity-boosting, in-field flowering strips were ‘a bit of a eureka moment’, and he has now rolled these out across the 800-hectare estate as AB8 and AB1 in Countryside Stewardship.

He said: “A personal positive for me was it’s an obvious way to bring in-field biodiversity which doesn’t detract from productivity as long you don’t run them to the headlands which would be impractical.

They are a good way to break up fields and wheat prairies.”

However, he does feel the economics need to be tackled better, with the model costing him around £900/ha in lost crop.

“In the short term they cost a fortune on this 12 tonnes/ha wheat land.

We are only getting around £500/ha from Countryside Stewardship [for the flowering plots].

[The losses] are worse this year with the high wheat prices.”

At the estate, collembola (springtails) and predatory ground beetles which eat slugs were more abundant in fields with in-field strips.

But measuring yield benefits was more complex, said Mr Gold.

Preliminary evidence However, across the whole Assist farm experimental network, which consists of 18 sites studied over four years, good preliminary evidence is emerging for how two sustainable management systems can boost yields.

With a focus on cereals and OSR, three models were explored – business as usual; the integration of cover crops and flowering margins; and the integration of cover crops, flowering margins, in-field strips and compost/farmyard manure Dr Ben Woodcock, ecological entomologist at the UK Centre for Ecology and Hydrology (UKCEH), said: “We see it takes time for these biological processes to respond, but both sustainable systems have yield benefits.

“For [the fields] with cover crops and field margins, we see by year four, which is the time it takes for populations of beneficials to increase, a 16.3% increase in yield.

For the more complex system yield increases are slightly higher at 17.9%.”

And while there is far more to sustainable intensification than yield, it is a crucial factor, he added.

“Preliminary results suggest sustainable intensification shows promise to support yields under real world conditions.

Yield increases can be achieved using flexible and simple management options that can be imposed over a range of farming systems.

But these do have running time before results occur which is likely to be a socio-economic barrier to uptake in future.”

To mark the end of the ASSIST programme members of the project team presented their preliminary results to the research community, policymakers and representatives of the agricultural sector.

To watch the event visit assist.ceh.ac.uk

How crop nutrition strategies can cut greenhouse gases

With two-thirds of the UK’s nitrous oxide (N2 O) emissions coming from agriculture, the Assist project has been exploring how to minimise emissions from soil through nutrient management, while maintaining productivity.

The study used innovative robotic sampling to capture variability in carbon dioxide, methane and nitrous oxide efficiency from up to 36 plots.

Last year’s work explored how biochar could limit nitrous oxide emissions in spring barley.

Nitrogen fertiliser was applied across the plots, with half receiving biochar.

However, unexpected heavy rainfall during establishment yielded some interesting results.

Although N2O emissions were very high in both treatments, where biochar was present the gas was suppressed by around 50% without any difference in crop productivity.

Presenting the findings, Prof Niall McNamara, group leader, plant-soil interactions at UKCEH, said: “It may be that biochar interacts with microbial N cycling processes and by doing so there is evidence it could mitigate N2 O emissions.”

In winter wheat strip treatments, nitrogen was applied at three different rates – two applications of 125kg N/ha; four applications of 62.5kg N/ha; and six applications of 41.6kg N/ha.

However, the split applications had no effect on cumulate N2 O emissions or crop yield.

Rainfall seemed the major determinant in driving N2 O emission peaks, exacerbated by the dry weather during the experiment, said Prof McNamara.

In another example where winter wheat was undersown with white clover to minimise mineral fertiliser use, the results showed that where white clover was in place and N reduced by 25%, crop yield was maintained but N2 O emissions fell by 20% due to lower soil inorganic N.

Climate change impact on nutrient leaching

Climate change alone could lead to reduced leaching of nutrients into the UK’s rivers, according to modelling of the UK landscape built by UKCEH and Rothamsted.

The modelling explored possible future river pollution scenarios including more intensive or extensive crop management, as well as changes to rotations and different climate scenarios.

Over the past 200 years, intensification of farming methods has influenced the quality of rivers.

Since 1800, N and P fluxes in rivers have more than doubled and agriculture is currently responsible for 78% of nitrogen, 44% of carbon and 28% of phosphorus inputs in rivers, UKCEH’s Dr Vicky Bell said.

Exploring Part of the Assist project has been exploring how landscape change could affect the quality of rivers in the future.

By 2050, according to UK Climate Projections UKCP18 climate models, the UK is set for warmer air temperatures, wetter winters and drier summers.

Dr Bell said: “If we keep farm management the same and only change the climate it could have quite a big impact on nutrient run-off into our rivers.

Early model results suggest from 2020-2050 climate change could alone lead to reduced farmland nitrogen run-off to rivers.

This is because crops will grow better with high yields.”

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2022-06-15T14:27:33+01:00June 15th, 2022|Blog Post|
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