GrowHow Agronomist releases Scotlands Soil Residual N Data
Across Scotland residual Nitrogen levels are broadly similar to this time last year according to data from GrowHow's 25 deep core sampling sites.
Company Agronomist Allison Grundy explains, "In terms of kg/ha the figures just announced show that average soil N levels in the 0 to 60cm profile across our Scottish sites are 34kg N/ha, just 0.5kg N/ha less than in 2008. Through a quirk of history most of the fields sampled in Scotland are on lighter/medium sites. Of the sites which are heavier residual Nitrogen levels are on average lower than in 2008.
Generally heavier soils take longer to warm up and are therefore slower to mineralise Nitrogen. This means the total N supply is lower. However heavier soils are more retentive and tend to lose less Nitrogen than their lighter equivalents. Throughout Britain the levels of residual N are consistently lower and this is probably due to the periods of wet weather the UK was subjected to during the autumn/winter period last year.
Whilst the Scottish data gives a good indication of what to expect, especially on lighter/medium soils, there can still be wide variations at farm level. "The best approach is for farmers to sample their soils and get them analysed through the GrowHow N-Min Service," advises Allison.
The N-Min Service is the only Nitrogen testing system which includes both Soil Mineral Nitrogen and Additionally Available Nitrogen to provide a measure of the total amount of Nitrogen the crop will be able to recover from the soil over the whole growing season.
"Knowing how much N will come from the soil is an important piece in the Nitrogen recommendation jigsaw and with the cold snap we're currently experiencing there's still plenty of time to get N-Min samples analysed - soil samples can be taken right up until first application," says Allison.
Across the UK, GrowHow takes 200 deep core samples which is by far the biggest dataset in the country. These deep core results are an integral part of N-Min as they are used to calibrate the system for the season. The deep core calibration model makes it possible for farmers and advisers to sample to a shallower depth but still receive data from deeper down the profile. Farmers and advisers only need to sample down to 30cm (or 60cm if organic manures have been applied in the last 24 months).
"With many backward crops about this year and now, evidence of low residual N levels, the temptation will be to get on with the first top dressing immediately," suggests Allison. "But, applying fertiliser in cold, wet conditions before crops start to grow will do no good. All that will happen is that Nitrogen will be lost from the system," she says. "Farmers need to hold off until things begin to warm up."
|
Mean N Measured (kg/ha) 0-60cm |
|||
|
Region |
2009 |
2008 |
% change |
|
1 Scotland |
34 |
34.5 |
-1 |
|
2 North East & Yorkshire |
35 |
49 |
-40 |
|
3 Eastern Countries |
44 |
67 |
-52 |
|
4 West of England |
39 |
44 |
-13 |
|
5 South & South East |
44 |
59 |
-34 |
GrowHow's N-Min Service can be accessed through FACTS qualified GrowHow Advisers, Fieldsmen and agronomists. For more information contact the GrowHow Advice Centre on 0151 357 5758.
For further information please contact:
Allison Grundy, GrowHow UK Limited Tel: 0151 357 5611 or mobile 07850 295096
Email: allison.grundy@growhow.co.uk
Helen Riby, Active Solutions Tel: 01623 656958 Fax: 01623 624167
Email: helen@activesolutions.uk.com
About GrowHow UK Limited
GrowHow UK Limited is the UK's leading manufacturer of ammonium nitrate and compound fertilisers.
Issued by Active Solutions on behalf of GrowHow UK Limited
