fbpx
Print this page
Wednesday, 18 March 2015 00:00

N. question hard to answer

Written by 

Is it worth applying nitrogen fertiliser to speed pasture recovery post drought?

 A Beef + Lamb New Zealand field day in North Otago, earlier this month, heard it’s a hard question to answer.

“The issue is how long has it been dry and whether there’s enough nitrogen [in the ground] to get that initial response,” AgResearch’s David Stephens said.

If there is enough N in the ground, grass will grow 450kgDM/ha from 15mm of rain, a 30:1 response. If there isn’t, the growth from that moisture may be halved.

Fellow speaker Graham Kerr said remember nitrogen is simply a growth multiplier. “If you’re growing zero, you’ll still get zero. If you’re growing a bit, you’ll get a bit more. If it’s growing well, then you’ll get a lot more.”

Whether the response to fertiliser would be economic would “depend on how desperate [for feed] you are,” he added.

“It’s a tricky one because you don’t know how much is going to be released from the soil. It really is quite variable. In general if you’re desperate for feed you put it on because by the time you see it’s needed it’s too late.”

If nitrogen fertiliser is applied it’s imperative to wait at least three weeks, preferably four, for pasture to use it. Grazing sooner risks nitrate poisoning and curtailing the plant’s growth response.

 

More like this

Nitrogen caps bound to fail

The Government’s decision to cap nitrogen fertiliser inputs at 190 kg N/ha per year is doomed to fail because it ignores basic science, claims soil scientist Doug Edmeades.

Getting smarter at growing grass

In his third season, sharemilker and Ravensdown shareholder James Barbour takes us through the farm’s approach to nutrient management.

Featured

 

Being a good boss during calving

Despite it being a busy time, being a good boss during calving is absolutely achievable, says DairyNZ’s People Team leader Jane Muir.

SFOTY in hot water over social media posts

Organisers of the NZ Dairy Industry Awards are investigating unsavoury social media comments allegedly made by the newly crowned 2020 Share Farmer of the Year, Nick Bertram.