Good nitrogen uptake whatever the weather

Good nitrogen uptake whatever the weather

Recent rain has been welcomed by farmers, but an eye on the weather is all important to ensure that nitrogen fertiliser applied to the soil is retained for pasture growth rather than being lost to the atmosphere.

Despite good rainfall, farmers shouldn’t think that good soil moisture levels and cooler conditions are enough to prevent ammonia loss from urea. New Zealand research has shown that ammonia loss actually increases with rising soil moisture, while risk of ammonia volatilisation shows no strong seasonality - meaning it doesn’t just happen in summer.

Recent Ballance Agri-Nutrients trials through Landcare Research suggests that 10 mm of rainfall is needed within 8 hours of application to minimise volatilisation and ensure the best nitrogen uptake, but MetService data shows that even with recent April downpours, the days with rain over 10 mm were not as common as farmers might expect.

For example, Wairarapa has recorded just six April days out of 27 with rain over 10 mm, Ashburton and the Waikato five, Taranaki four, Whangarei, Rotorua and Palmerston North three and Taupo just two.

Ballance Science Manager, Aaron Stafford, says that at the upper end of the scale, some areas experienced more than 50 mm of rain two days in a row, meaning that if urea had been applied, direct leaching would become a risk. This means the window for safely applying urea was further reduced.

“In reality with these weather patterns you are unlikely to get above 10 days a month that meet the criteria to mitigate volatilisation with ideal weather, which means that unless you get lucky, you’ve got around a 70% risk of applying it at a time when volatilisation is likely to occur. Can you afford the risk?”

Using a product like SustaiN, which is urea coated with AGROTAIN® nitrogen stabiliser, offers farmers more flexibility to apply nitrogen without trying to second-guess the weather – with subsequent improvements in nitrogen availability and uptake resulting in more dry matter per hectare.

“We know SustaiN showed an average 50% reduction in ammonia volatilisation relative to urea, so unless it is actually raining when you apply urea, or you can guarantee 10 mm of rain within 8 hours, it is a better solution for minimising ammonia loss and therefore harnessing the best response possible from your nitrogen fertiliser investment.

“In short, using a product like SustaiN is your safest bet to ensure that your investment in urea is going to bring you the best returns – rain or shine.”

ENDS

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