26 May, 2017
Applying fertiliser in dry conditions – A tricky decision?
As the time of writing this we haven’t had much rain to speak of for about 6 weeks. October to March has been the driest it’s been for 20 years according to the Met Office and April has had less than 30% (across most of the country) of the 1981-2010 average rainfall totals.
Does this mean that you need to change your fertilizer strategy? This needs to be done with caution as in other dry years, such as 2011, the total fertiliser still provided a 4:1 return on investment despite the dry conditions. This was giving a ROI of £2.16-£3.30/ha from the final 60kgN/ha application – therefore changing your plans might be more costly than you think.
Problems with these dry conditions are that farmers are concerned about seeing the fertilizer sitting on the surface. If you have applied ammonium nitrate then don’t worry as losses of nitrogen will be minimal (1%), if however, you have applied urea then losses will be much greater at about 15-20% of the nitrogen you applied.
Yara’s Nitrogen source trials that are in the ground this year are showing that in the Urea plots the crop has taken up less nitrogen than in the ammonium nitrate plots – this is due to nitrogen losses being 15 times higher in the Urea than the AN.
When thinking about late foliar nitrogen then it is best to be cautious. If we continue to have very dry weather, where the crop is under stress, then applying foliar urea could lead to scorching the crop and therefore having a detrimental effect on yield. If we have normal rainfall in May then this shouldn’t be a problem but it is something to bear in mind before making the decision.
Cereal agronomy advice
