Arable crops

Yara commissions independently conducted field trials each year, gathering data that is relevant to improving nutrient efficiency on-farm and giving this knowledge to growers to utilise.

The 2023-24 season had particularly difficult growing conditions, as you will well know, however we can glean some useful insights in a challenging year from trial work. The optimum nitrogen rate (or N Opt) is calculated each year from the various nitrogen dose response trials we conduct. It takes into account crop and fertiliser pricing to get the optimum nitrogen rate in terms of economics and crop yield. Yara has this data stretching back 30+ years but in more recent years the N Opt has been an average of around 200 kgN/ha (feed wheat).

If we look at the trials from this year, we see that the N Opts are much higher, averaging a very high 275 kgN/ha across 6 sites (ranging from 219 – 361kg N/ha)– why is this? I don’t need to remind anyone of the awful conditions of autumn 2023, that level of excess rainfall affected the fertility of the soil by washing nutrients, normally held there, down the soil profile and therefore being lost to crops.

When we look at the untreated control plots, they yielded much lower than usual, showing that the level of nitrogen that was mineralised was less than that of an average year, as expected from unusually high levels of rainfall. The low soil N levels also affected the grain N % and protein %, with only the 300+kgN/ha plots reaching protein spec, in one case even the highest rate of 340kgN didn’t get to 13%.  

Whilst this doesn’t sound like a very positive picture, what we can do is learn from it to change the nutrition strategy, if we are faced with similar conditions in the future. Potentially saving you from being disappointed with yields or proteins when the same nutrition strategy as a normal year is used, instead of adapting it for when conditions are challenging.