Wet weather conditions in recent months may have led to nitrogen leaching further down the soil profile than usual, reducing availability to some crops, however, the situation can vary widely between farms and needs to be monitored.
CF agronomist Ali Grundy says there is a perception that because soils are wet there is no nitrogen. “It depends on soil type and how much nitrogen comes from organic matter. If soils are very light, what nitrogen there is could have been leached further down the profile but this is not the case for every farm.
“Measuring is the key thing. CF N-Min analysis is a measure of what is available for the crop to get hold of and N-Calc can work out how much you need to apply.”
Ms Grundy is concerned growers will rush to apply N as soon as the closed period ends. “You need to manage the crop in front of you, not do what you did last year. If you have a winter crop that has survived it is likely to have a small root system and will more than likely be a small crop. If you put a large slug of nitrogen on early, recovery of it by the crop could be poor. Be prepared to apply more frequent, smaller dressings.”
For growers looking to put N on early, a first nitrogen application as low as 20kg/ha could be appropriate and applications as frequently as 10 days to a fortnight, says Ms Grundy.
“Understand the yield potential of smaller crops. It is best not to go for a huge yield that it is impossible for crops to deliver. If the weather improves, you can always change strategy.”