GROWERS are being urged to make strategic decisions about nitrogen application before sowing to maximise fertiliser efficiency throughout the crop’s growth.
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The main driver of yield and grain quality is the nitrogen rate, not the timing or the method of application, according to Northern Grower Alliance chief executive Richard Daniel.
Nine crop trials run over the past two years have focused on the timing and method of nitrogen application, but the results has shown that the rate is more important.
Five nitrogen application approaches – disc drilling pre planting, spreading on the soil surface, spreading immediately before sowing and incorporated by sowing with narrow point tynes, spreading immediately post sowing and spreading nitrogen in-crop at growth stage 30 – were evaluated using standard urea at application rates of 50kg, 100kg and 200kg of nitrogen per hectare.
“This research is supporting the idea that if we were to top up nitrogen within the crop, we’re probably in a much less risky situation than we thought,” Mr Daniel said.
“That means the grower has more flexibility in when and how they apply nitrogen.”
He said the key was to match the nitrogen rate to the soil moisture and the crop’s estimated yield potential. He recommended growers plan to apply nitrogen in-crop as well as at planting.
“Crops that have a high nitrogen rate at the time of planting have looked great in September, but they’ve hit the wall in the last month or six weeks before harvest,” he said.
“The risk of using high rates of nitrogen at planting is producing too big a crop early and running out of moisture which causes more pain from a yield point of view.
“In a lot of situations where people planting are on half a profile of moisture, they can go very easy with nitrogen rates and if the expected wetter than average winter materialises, look at top-dressing in July or even into August, because we know they won’t lose yield potential by delaying to that stage.”
Mr Daniel said there was a wide window of opportunity in which growers could get good yield response from added nitrogen.
“It’s unlikely that we’ll ever get to putting half the nitrogen in at planting and always top it up, but if you put on what you think you need at planting and the moisture improves in winter, you then have the opportunity to take advantage of the season if it’s going in your favour.
“Growers need to keep it as simple as possible – don’t worry too much about how it’s applied or when, just focus on the nitrogen rate.”
