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Fertiliser additives deliver big savings and improved soil health

News - 30.01.25

Transforming Soil Health: How You Can Improve Crop Efficiency and Reduce Emissions

Improving Soil Health at Sparsholt Manor Farms

Efforts to improve soil health at Sparsholt Manor Farms in south-west Oxfordshire have begun to yield positive results. Nitrogen-to-carbon ratios have gradually improved to the desired 10-12:1 level while reductions in carbon emissions have provided a valuable new income stream in the form of tradeable credits.

The transformation at Sparsholt Manor Farms, located on the Lambourn Downs outside Wantage, began in 2014 when issues with black-grass led to a change in the cropping regime. The farm transitioned from a three-year rotation to a seven-year policy incorporating two successive years of spring crops.

This was supported by long-term use of cover crops, a move to reduced tillage establishment practices, and the inclusion of fertiliser additives to improve crop efficiency and reduce environmental losses.

“The black-grass legacy drives most decisions, but it led to a series of changes that have culminated in a steady yet sustained improvement in soil health and the reduced use of nitrogen fertiliser while enabling the business to access new income streams,” says Piers Cowling, farm manager at Sparsholt Manor Farms.

 

Building Organic Matter Through Cover Crops

Winter wheat still forms the basis of the rotation, covering about 600 hectares of the farm’s 1100 hectares of arable land, with oilseed rape, spring beans, and spring barley making up the remainder. The introduction of back-to-back spring crops in the middle of the rotation led to the adoption of cover crops as a means of building soil organic matter.

This has been further enhanced by companion cropping oilseed rape with berseem clover and fenugreek. Since 2018, soil organic matter content across the farm’s heavy clay loam with chalk has increased by an average of 2%, a significant achievement for a long-term arable farm with no imported manures or digestates.

“In some situations, the high organic matter contents are creating difficulties at cultivation and drilling, but we have found that this can be overcome if we time activities according to soil moisture levels,” adds Piers.

 

Controlling Black-Grass While Boosting Fertiliser Efficiency

The black-grass situation has been brought under control, but there is recognition that the success of the past decade could be undone in a single season if it escapes efforts to manage it.

Alongside better rotations, two fertiliser additives have contributed significantly to increased efficiency and reduced environmental impact:

  1. Liqui-Safe – A urease and nitrification inhibitor containing NutriSphere-NL, which has allowed reduced application rates and fewer passes without compromising yield.
  2. Fortis CP – A molasses-based high-carbon and free sugar formulation applied at 5 litres/ha, helping to improve fertiliser absorption and reduce crop scorch.

“We were early adopters of Liqui-Safe because it enabled us to cut application rates and reduce the number of passes needed without compromising on yield,” explains Piers. “More recently, we have begun adding Fortis CP, which helps to increase the efficiency of fertiliser absorption, and we have seen reduced crop scorch from its use.”

Both products are now applied in combination at every fertiliser application and across all crops.

Over three years, nitrogen rates in winter wheat have been reduced from a farm standard of 220 kg N/ha to 160 kg N/ha, with the number of splits reduced from three (80:80:60 kg N/ha) to two (80:80 kg N/ha) without yield penalties.

“We believe there is scope for further savings in application rates, so we will continue to trial how much to apply at each split to identify the optimum rate,” he adds.

 

Generating Carbon Credits Through Improved Soil Health

The improvements in soil health and savings in crop inputs have been overseen by Iain Richards, agronomist at Agrii.

“There was an acceptance that if the cover crops and stubbles we were incorporating were to truly benefit our soils, we needed to feed the microbes. Crop residues are part of the food web, but bacteria need energy to do their job. The free sugars in Fortis CP have been central to achieving this,” he explains.

Using Agrii’s Green Horizons service, the farm has tracked its carbon emissions (in CO2 equivalent) since 2017. From 0.43 kg CO2/kg of output, emissions fell to 0.32 kg CO2/kg of output in 2022, and after reductions in nitrogen fertiliser applications and cultivations, to 0.17 CO2/kg of output in 2023. The savings were traded within the supply chain, generating an additional income of about £20,000 (£18/ha) in the 2023-24 marketing year.

“Reducing emissions not only benefits the environment but also provides a valuable new income stream for the business,” says Iain.

 

A Shift in Crop Protection Strategy

As soil and plant health have improved, other changes have followed. The T0 spray is now based around foliar nutrition and endophytes rather than conventional fungicides. As a result, product costs at this timing have fallen by about £60/ha compared with the previous approach.

“The switch to a more biological approach at T0 has reduced costs and maintained disease control, which is a win-win for us,” says Iain.

 

What is Fortis CP and How Can It Benefit You?

Fortis CP is a crop nutrition spray made from co-products of the sugar industry, produced by ED&F Man Commodities. It is high in carbon (23%) and sugar (67%), making it particularly suitable for pairing with foliar nitrogen applications to mitigate both sun and frost scorch while improving nitrate metabolism in crops.

 

Key Benefits of Fortis CP:

  • Improves nitrogen use efficiency
  • Enhances soil microbial activity
  • Reduces nitrogen application rates by up to 20%
  • Mitigates crop scorch from environmental stressors

Application rates vary from 5 to 8 litres/ha, with a maximum of 30 litres/ha per season. With a typical application cost of £4.25/ha, the nitrogen savings more than cover the product cost.

“It's a small investment that pays for itself in nitrogen savings and overall crop health,” explains Tom Perrott, Agrii crop input specialist.

 

Fortis CP supports higher yield and greater soil bacteria 

 

Yield
(t/ha)

Total bacteria (microgram/gram
of soil)

Total Fungi (microgram/gram of soil)

Untreated

3.4

315

274

Farm standard
(150kg N/ha)

6.11

315

217

Farm standard -20%
(120kg N/ha)

6.12

263

241

Farm standard
+ Fortis CP

6.17

604

269

Farm standard -20%
+ Fortis CP

6.28

393

270

Reference: Agrii, Dorset, 2024. Cv. Skyway, spring barley.
All PK&S applications were balanced and equal across the plots

The Future of Sustainable Farming

By adopting innovative solutions like Liqui-Safe and Fortis CP, you can enhance soil health, improve nitrogen efficiency, reduce emissions, and unlock new income streams.

"The transformation at Sparsholt Manor Farms shows that with the right strategy, small changes can lead to big results," says Iain.
"We’re excited to see what the future holds as we continue refining our approach."

Meet the Contributors

(From left to right): Tom Perrott, Agrii, Alistair Hugill, ED& F Man, Piers Cowling, Sparsholt Manor Farms, and Iain Richards, Agrii

Read more: Agrii-Fortis CP

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