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Profit from CF N-Min sampling

Chris Peach

Farmer: JT Peach & Son, Lincolnshire

Crops grown: wheat

Yield gain: yields up to 1.5t/ha

MOFC: extra £172

Fertiliser used: Nitram®

CF N-Min soil N test delivers best-ever wheat yields

The CF N-Min test and improved Nitrogen (N) recovery had a profound effect on wheat yields despite the challenging growing conditions of 2018 by producing much higher yields.

Both fields that were selected for the trial are similar in terms of being Grade 1 silt but very different in terms of previous cropping. Post Office Field’ had high levels of residues from the previous crop of broccoli. In contrast, daffodil bulbs grown on ‘Black Hole Drove’ during the three previous years had received only a small amount of base fertiliser in the spring after planting and when they were lifted in July 2017 left very little crop residue.

The test results showed a wide variation in Soil Nitrogen Reserves:

  • For Post Office Field the N-Min result was 149, giving an SNS of 179, a figure which even surprised Arthur
  • At Black Hole Drove the N-Min was just 44 and the SNS 74 reflecting the fact the field had been into bulbs and received no additional Nitrogen for three years.

With a target yield of 12t/ha, the recommendations were 87kgN/ha for Post Office giving a total fertiliser cost of £48/ha and 238kgN/ha, costing £132/ha, for Black Hole Drove. The mean of £90/ha for the two fields was substantially higher than the £72/ha it would have been under the farm’s previous blanket rate N application, with all Nitrogen applied being CF Nitram (34.5%N) at £190 per tonne. The exceptionally dry spring and summer meant yields from both fields were less than they might have been, but they exceeded previous average yields.

Post Office, the high-residue field, yielded 9.6t/ha while Black Hole Drove, the low-residue field, produced 8.7t/ha, giving a mean of 9t/ha, significantly more than the 7.5t/ha for the standard farm programme.”

Average Margin Over Fertiliser Cost (MOFC) was £1420/ha where N-Min was used, compared with £1248 for the standard farm programme, justifying the cost of using the N-Min service many times over.