Blue Bags Grow Better Crops


Using CF Fertilisers advice, GB & GM Stafford were able to save money and significantly increased yields and gross margins from two key crops at Pickwick Lodge Farm, Corsham.


Combining recommendations from CF N-Min soil analysis with the use of a spring-applied NPKS compound in the form of CF Heartland Sulphur (24-8-8 (8SO3), the business increased its margin from KWS Cassia winter barley by £121.50/ha over standard farm practice, and by £229.00/ha in the case of Dekalb V3160L oilseed rape, a new HOLL variety.



GB & GM Stafford have relied on CF N-Min testing and analysis to optimise their fertiliser inputs for more than a decade. The service is particularly important because 10 per cent of the farm is situated in a water abstraction zone, so optimising nutrient use is essential.


“Unless you measure the Nitrogen which is in the soil you cannot manage the Nitrogen that you apply,” James emphasises. “Because we apply manures in rotation it is essential for both environmental and economic reasons to use CF N-Min testing so that we use appropriate amounts of additional nutrients. Sometime this means putting on more than we might have done based on standard guidelines, at other times less, which can be difficult to accept. One year, for example, the N rate recommended by CF N-Min for oilseed rape was just 125kg N/ha, but the yields confirmed that it was correct.”


The service is particularly recommended for use in new fields, those with an unknown history, where organic manures have been applied, where high organic matter is present in the soil, where the farm includes a diverse range of soil types and in fields which have grown crops that leave behind large residues of nitrogen.

Samples are sent to Hill Court Farm Research, an independent laboratory where they are analysed for SMN content and incubated to establish how much AAN will become available. CF’s N-Calc System then uses the Soil Nitrogen Supply (SNS) and N-Min result plus Spring Crop N to calculate the optimum Nitrogen input for cereals and oilseed rape.

“The other major advantage of the Heartland System, and the reason we would rather use it, is that you only have to deal with one product to do everything, which makes storing and using fertiliser much easier.” 


To establish a baseline for Nitrogen requirement, James Stafford’s adviser Ross Leadbeater, Business Manager for CF Fertilisers, took N-Min samples in the trial fields to provide a reference point. The results highlighted a requirement of 225 kg N/ha for winter barley. The farm’s standard practice of applying Nitrogen Sulphur in late February or early March, followed by top dressings to supply the remaining Nitrogen in April, the KWS Cassia delivered a yield of 8.85t/ha, valued at £1062/ha. Where the N-Min approach was used in combination with Heartland Sulphur, yields increased to 9.8t/ha, worth £1176.00, without increasing Nitrogen input.


The effect of this was to increase margin over fertiliser cost from £840.75/ha for the farm practice crop to £962.25/ha for the N-Min approach, representing an additional £121.50/ha.


In the case of oilseed rape, N-Min highlighted the need to apply 150kg N/ha. The standard farm practice again being a combination Nitrogen Sulphur followed by straight Nitrogen  At harvest, this approach produced a yield of 3.11t/ha, worth £1088.50/ha and a margin after fertiliser costs of £941.00. The Heartland Sulphur system generated a yield of 3.75t/ha, worth £1312.50, and a margin over fertiliser costs of £1170.00, representing an additional £229.00/ha.

With the base-line Nitrogen requirement established by N-Min for both treatments the performance improvement from the CF N-Min treatment came from additional elements of P, K and S in Heartland Sulphur driving better Nitrogen utilisation. James Stafford says the trials point the way to a rethink of a fertilising system which is delivering significant increases in yield.

“We have been applying Heartland Sulphur on our grassland for years, with one application in March and a second 35 days before the first cut of silage is taken. The results have always been excellent, particularly on our Cotswold Brash, but this was the first time that we had tried it in an arable situation, James explains. “Our experience highlighted definite advantages from using the spring-applied NPKS compound in the form of healthier plants, higher yields and additional financial margin”

James believes that the new system could have even greater applications and is researching the use of variable rate seeding to manipulate crop growth and performance.

CF’s Ross Leadbeater adds:

“These results mirror other farmers’ experiences of spring-applied NPKS compounds and highlight the importance of thinking beyond the headline ‘cost per kilogram’ of nutrients by considering the overall picture. Spring-applied NPKS compounds are slightly more expensive because they are more complex to manufacture, but this is inconsequential compared with the additional performance they deliver. Principally this because they ensure that crops receive the nutrition they require, in the form they need it, when they need it”


“Farmers’ experiences of spring-applied NPKS compounds highlight the importance of thinking beyond the headline ‘cost per kilogram’ of nutrients,” says Ross Leadbeater of CF Fertilisers.