Blue Bags Grow Better Crops



Balancing the need to control blackgrass with production of premium crops has put the focus directly on optimum fertiliser management at one Lincolnshire arable farm.

Accurate Nitrogen management has proved invaluable in getting the best economic returns. The need to reduce wheat area to make room for more spring crops in the fight against blackgrass, means maximising milling wheat premiums is no longer a luxury for farm owner Chris Richardson but an absolute financial necessity.

“Our spring cropping increased to 50% this year and our wheat area has dropped from over 200ha to just over 130ha. Our approach has always been to grow for premium markets so we’ve kept the 70ha of wheat grown for seed that we have always had and our aim is now to put the remainder into milling varieties”

ACT eastern area manager Arthur Baldwin and Lincolnshire grower Chris Richardson

 “By far the most important aspect of crop management for us is how we use our fertilisers – not just in terms of achieving maximum yields for the lowest cost of production but also so we can consistently achieve the premiums we are targeting.”

His approach starts with CF N-Min testing with Arthur Baldwin of ACT routinely taking soil samples from representative fields at the start of the year to ascertain what Nitrogen is currently in the soil and what is likely to become available as the season progresses.

“Understanding soil reserves is essential if you are to make the right decision regarding how much fertiliser to apply. A simple soil test will only tell you how much Nitrogen is available in the soil at that moment in time,” Arthur Baldwin explains.

“But to really work out how much fertiliser you will need you have to know how much Nitrogen will be mineralised in the soil and become available to the plant after the test.”

This additional reserve is called Additional Available Nitrogen (AAN) and is a key component of calculating the overall Nitrogen requirement, he says.

“It’s particularly important in premium crops. In the malting barley crop Chris grows, applying too much fertiliser will push grain Nitrogen levels above those stipulated in the contract but applying too little will reduce yields.

“In milling wheat if you apply too little Nitrogen not only will you lose out on yield you could also fail to meet the protein content required.


Recent trials organised by CF Fertilisers at the farm have in fact shown the critical importance of this with the variety Skyfall, Arthur Baldwin explains.

“Skyfall is very hungry but there seems to be a point at which additional Nitrogen does not produce extra yield or quality, so being able to identify what the critical level is enables us to maximise returns from the crop.”

In the trials, the plots with the farm’s standard practice of applying 250kg N/ha delivered a yield 11.19t/ha whilst those with the N-Min advised application rate of 215kg/ha from DoubleTop (27N (30SO3) and Nitram (34.5N) applications, produced a yield of 11.57 t/ha.

The combined effect of the 16% saving on applied Nitrogen – £139.75/ha as opposed to £162.50/ha – and the additional yield produced add up to an increase in margin of £72.91. Despite the lower application rate, the N-Min crop still produced the required 13.0% protein.

Table – 2016 Skyfall Fertiliser Trials - Grove Farm, Swaton, Lincolnshire


N rate

(kg N/ha)

Ferts + SNS

(kg N/ha)


















- 594.58

N-Min 150 (target 10t/ha)








N-Min 215

(target 12t/ha)








Farm prac.









Such findings are fine-tuning Chris Richardson’s approach with all the Skyfall on the farm last year consistently achieving ten tonne yields at protein levels of over 13.0%.

“All our crops now get 150kg/ha of DoubleTop as a first application so we know we have the right amount of Sulphur going on.

“This provides 40kg N/ha and, depending on what N-Min is telling us, we will then follow this up with two dressings of straight Nitram to provide another 90 – 240kg N/ha for the seed crops.”

Whilst these crops typically receive 200 – 250kg N/ha of additional fertiliser this way, an extra dressing of N is usually applied to the milling crops taking this up to around 300kg N/ha, he says.

“We learned that if we want to get a ten tonne crop of Skyfall, eleven tonnes if possible, at 13.0% protein, we have to fertilise the crop as if it was a twelve tonne crop.

“In nine years of out of the ten we have been conducting trials, N-Min has delivered a significant economic advantage. The tenth one was break even.” Chris Richardson

The Nitrogen policy for the barley follows a similar approach with 40kg N/ha initially coming from DoubleTop and N-Min supplying the base information for working out subsequent applications of Nitram

“Depending on soil reserves, these have been between 16kg N/ha and 200kg N/ha but generally we target a 10t/ha crop and last year – our first year with crop – we achieved 8.5t/ha which is a good starting point.

“We can go up to 2.1% grain N on our contract which is higher than some and this is good for us because the bigger the crop the greater the smothering effect on the blackgrass – which is one of our main objectives of growing the crop.

“But again, achieving the high yields without going over the allowed Nitrogen level requires a level of precision that I just don’t think we would achieve with a less sophisticated approach. Our focus of growing premium crops for high value markets will continue and ongoing monitoring of soil nutrient status so we can apply the most appropriate products to achieve”.