Bad weather prompts nitrogen soil fears
Some advisers are recommending that more nitrogen be applied, as a matter of course, but with ammonium nitrate at around £300/t the cost of applying extra nitrogen cannot be ignored.
Targeting additional nitrogen applications to those fields which actually need it makes good economic sense.
Nitrogen losses will mainly come from leaching but where soils have been waterlogged or even underwater for long periods denitrification may also occur.
According to Sean Stevenson from analytical services specialists, NRM, "The exact extent of nitrogen losses through leaching and/or denitrification following heavy or sustained rainfall can be hard to quantify."
"It is the nitrate form of nitrogen that is susceptible to loss though leaching and denitrification so the extent of any loss is governed by the amount of the crop nitrogen supply that was in the nitrate form when the rainfall occurred."
Other factors also influence the extent of nitrate losses, application timing, soil characteristics the type of nitrogen fertiliser and so on.
In general leaching losses are more likely on sandy soils and denitrification more apparent on medium and fine textured soils that have poor drainage.
However the only way to be sure of how much nitrogen is in the soil is to conduct a soil mineral nitrogen test.
Stevenson explains further: "Soil Mineral Nitrogen is the nitrate-N plus ammonium-N content of the soil within the potential rooting depth of the crop."
"When estimating the total amount of N that will come from the soil – that's the Soil Nitrogen Supply (SNS) – you also need to include an estimate of the N already in the crop and an estimate of the mineralisable soil N. A test is also available from NRM to determine this mineralisable value.
"Once you have your SNS index you can use The Fertiliser Manual (RB209) to determine the correct fertiliser nitrogen recommendation."
No comments posted yet. Be the first to post a comment
Please enter your name
Please enter your comment
Your comment submitted successfully.Please wait for admin approval.
Some error on your process.Please try one more time.
The permanent eradication of Bovine Viral Diarrhoea [BVD] in Scottish cattl...
The abolition of milk quotas in Europe on 1st April has resulted in a numbe...
The top 14 milk producing countries in Europe will increase their productio...
Matt Ware is the NFU's head of government and parliamentary affairs, based ...
There is a 'desperate need' to improve farmgate returns given low incomes a...
Rapid stem extension, after a slow start to spring, is likely to create spl...
The time has come for landlords to expect to see reductions in farm rents, ...
Cogent’s reputation as a source of the highest calibre sires has been enhan...
The spread of exotic and aggressive strains of a plant fungus is presenting...