Practical ways of minimising soil movement without raising crop return risk, insuring against the worst the weather can bring, targeting the most rewarding Sustainable Farm Incentive (SFI) soil standards and maximising carbon capture are among the key drivers behind development of a Soil Resilience Strategy (SRS) service launched by agronomy firm Agrii.

Acknowledging that soil heath is a core component of the Governments SFI under the Environmental Land Management (ELM) scheme, the company says it has developed its SRS to provide a framework for monitoring soil health and to help to identify ways of best meeting SFI obligations.

Development

Inputs for development of SRS have included studies with groups including the UK Centre for Ecology and Hydrology (UKCEH), to form a strategy influenced by the latest soil structure, chemistry and biology research.

Agrii sustainability manager Amy Watkins says: Our aim has been to provide farmers with a structured approach to improving soil resilience based on the best available science, a thorough understanding of soil management and sound practical advice and action.

Developed from recent work with UKCEH and others, among other things SRS will provide growers with all they need to qualify for the SFI Soil Standards in 2022 and beyond.

In practice, this means our soil management advisers provide flexible packages of laboratory and field-based assessments designed to suit varied soil conditions, farming systems and business needs.

These are supported by a range of lab tests and in-field appraisals to assess soil health.

By working according to Amy Watkins each farms particular objectives, needs and resources, the aim is to work with farmers to develop appropriate progressive improvement plans to enhance productivity and sustainability and capitalise on SFI soil standards payments.

Under its Green Horizons banner, Agrii is providing SRS via its national agronomist network and its Rhiza digital agronomy specialists.

Users signing up to the service will initially be provided with a full soil health assessment involving broad spectrum laboratory nutrient, pH and organic matter testing.

Further analysis can be added, including detailed measurements of soil carbon at different depths, in-field soil biology, structure and water management assessments, worm activity monitoring, visual evaluation of soil structure (VESS), and penetrometer, slake, aggregate stability and infiltration testing.

These tests can be carried out on a sample of fields representative of the farm as a whole or on those posing particular management concerns.

Critical considerations in the assessments and their use include understanding the particular objectives and constraints of the farm, knowing the cultivation and cropping history of the fields assessed and selecting fields carefully on the basis of individual grower needs, plus taking samples that are as representative as possible of field status to generate consistent comparative data, says Ms Watkins.

In-depth initial assessments ideally need following with seasonal snapshots and full retesting every three to five years, ideally with active carbon monitoring in between, making future assessments at the same time of year and under similar conditions.

Carbon accounting

In developing SRS protocols we also took into account the need to adjust for bulk density, chalk and stone content for accurate carbon accounting.

Making biological assessments at the best time, preferably in spring, is also essential, as is recording the weather at the time of each assessment.

Organic matter testing is carried out consistently using the same proven process, preferably the Dumas method which measures the CO2 emitted by a soil sample after combustion.

Standard field reports have been developed to practically and clearly present the results for benchmarking and improvement planning, says Ms Watkins.

The reports are intended to give an objective and scientifically-valid record of soil status, allowing individual farms to set realistic objectives for improvement, monitor success in meeting them and increasingly importantly for the future demonstrate progress to others, be they customers, carbon offsetters, agricultural support providers or the general public.

To encourage the widest possible participation, Agrii says it has closely aligned SRS charges to its standard consultancy and laboratory rates.

Service cost depends on the specific assessments selected, the number of fields included and the frequency of retesting.

While lab and field assessments from analysis produce data with a useful role in benchmarking, it is the practical action plans which can be created from them that are of the greatest value, says Andrew Richards, senior agronomist at Agrii and a key member of the SRS development team.

Only by combining a detailed understanding of each growers resources and objectives with the best intelligence on all aspects of soil health and its management can assessments be translated into the most appropriate improvement action, he says.

More fundamental soil health constraints like pH, for instance, need to be addressed before further action is justified after initial soil assessment.

The same is true of moving to direct drilling without ensuring ground is ready, or targeting levels of organic matter improvement which are unrealistic for the soil and the farming system.

Resilient

Among other things, our work with UKCEH has shown the clay:carbon ratio of soils is a much more useful measure of resilience than organic matter alone.

Because clay particles bind organic matter, the greater a soils clay content the more organic carbon it can store, but the higher the level it will require to be resilient and the slower it will be to build.

We have therefore made this central to the Soil Resilience Strategy.

Only by establishing exactly where soils sit on the clay:carbon resilience scale can we provide practical recommendations for both soil health and soil carbon storage improvements