Local Govt | National News Video | Parliament Headlines | Politics Headlines | Search

 


Rain a blessing – but watch for nitrate poisoning risks

8 April 2014

Rain a blessing – but watch for nitrate poisoning risks

Rain is high on farmers’ wish list as the run of dry weather in many regions is affecting pasture growth. But nature’s blessing can come with a sting in the tail with the risk of nitrate poisoning in stock increasing when a dry spell is followed by rain or a run of moist, overcast days.

“During a severe drought, lack of moisture stops plant roots from absorbing nitrate. When the rain finally arrives, roots suck up nitrate rapidly, with the pasture accumulating high levels in the stem and leaves,” says Ballance Science Manager Aaron Stafford.

“After a drought-ending rain, it could be two weeks before nitrate levels in pasture stabilise at safe levels, provided environmental conditions are favourable. Hail or light frost can also damage plants, affecting photosynthesis and leading to elevated nitrate levels.

Aaron says plants usually absorb soil nitrogen as nitrate and convert most of it into ammonium and amino acids. But weather conditions in late autumn and winter can sometimes interrupt the conversion process, increasing the risk of nitrate poisoning.

All ruminants can be affected. Cattle are the most susceptible, sheep the least and young stock is more vulnerable than old. Nitrate poisoning sets in rapidly after an animal eats pasture or feed with excessive nitrate levels (0.21% or 2,100 parts per million and above is considered ‘at risk’).

Aaron says rape is known for high nitrate levels, closely followed by other brassicas. Vigorous ryegrass (especially annuals) can create problems, as can cereal green-feeds. Nitrate concentrations are generally higher in new plant growth and decrease with age. Stalks are highest in nitrate content, followed by leaves and then grain. Notably, young pastures (e.g. those re-sown in the last 1-2 years) generally present greater risk to grazing livestock than older pastures.

“Nitrate poisoning progresses quickly and has no ready cure so prevention is important. Testing pasture and feed for nitrate is one option but there are other ways to mitigate the risk.”

Farmers who suspect they have a high nitrate risk can use the following strategies:
• Split nitrogen applications late in the season to distribute nitrogen better. Apply nitrogen after grazing.
• Don’t put hungry stock on high-nitrate feeds. Give them a low-nitrate feed first, preferably one that takes a while to digest (such as straw or hay) so they are less likely to gorge themselves on risky pastures.
• Dilute high-nitrate feeds with low-nitrate feeds. This helps microbes in the rumen adapt to high nitrate feeds. Adjustment can take three to four weeks.
• Pasture nitrate levels are highest overnight and in the morning. Where possible constrain stock access to pasture (particularly in the morning grazing) until animals have been supplemented with low nitrate feed. This could involve in-shed feeding, use of feed pads or laneways, or fencing off areas on pasture to feed out supplementary feed and reduce pasture access.
• Minimise stock intake of pasture in the first 1-2 weeks following drought-breaking rain. This requires adequate supplementary feed to cover this most at-risk period.
• Stock lightly, so animals can selectively graze and avoid hard grazing - the lower part of stems have the highest nitrate content.
• Provide a lot of clean drinking water for stock on high nitrate forage.

ENDS

© Scoop Media

 
 
 
 
 
Parliament Headlines | Politics Headlines | Regional Headlines

 

PARLIAMENT TODAY:

Gordon Campbell: The PM’s Hair-Pulling Power Trip

There have been striking differences between (a) the account of the waitress involved in the hair-pulling incidents, and (b) the account being given by Prime Minister John Key. The version by the waitress is available here and is recommended to anyone yet to read it. By her account, there were multiple instances of hair-pulling and these persisted and persisted long after she had made her annoyance clear to Key – who had also been advised by his wife, and by other café staff that the behavior was evidently not being welcomed. More>>

ALSO:

War: What’s To Commemorate?

Gordon Campbell in Werewolf: Is there anything that can be validly commemorated on this 100th anniversary of Gallipoli? Beyond, that is, a fleeting sense of empathy with the thousands of soldiers killed or wounded on April 25 1915 and in the months thereafter, until the whole thing was finally called off in December 1915. More>>

MORE IN WEREWOLF:

ALSO:

Peter Ellis Case: Minister Declines Request For Commission Of Inquiry

Justice Minister Amy Adams has declined a request from supporters of Peter Ellis for a Commission of Inquiry on the basis that an inquiry cannot be used to determine the liability of any person. More>>

Quakes: New Process For Red Zone Crown Offers

Canterbury Earthquake Recovery Minister Gerry Brownlee has announced a process to give everyone a say on the Crown offers to owners of vacant, commercial/industrial and uninsured properties in the Residential Red Zone. More>>

ALSO:

Gordon Campbell: On The Battle Obama Is Waging Over The TPP

For the past two and a half years, this column has been arguing that the fate of the Trans Pacific Partnership (TPP) deal will hinge on whether US President Barack Obama can win Trade Promotion Authority (TPA) from Congress... Last week, the White House finally, finally unveiled a draft TPA Bill. More>>

ALSO:

Greens: Govt Breaks Free Doctors Visit Promise To Kids

Documents obtained by the Green Party show that the Government decided to fund only 90 percent of doctors’ visits for children suffering from an injury in an attempt trim the cost of the so-called “free” visits. More>>

ALSO:

Other Wars: Extension Of NZDF Commitment In Afghanistan

The New Zealand Defence Force’s commitment of mentors and support staff to the Afghan National Army Officer Academy in Afghanistan has been extended out to December 2016, Defence Minister Gerry Brownlee says. More>>

PM's Press Conference: Auckland Property Prices Increasing "Too Rapidly"

John Key accepted that Auckland property prices 'are going up too rapidly” in a press conference held today in Wellington, however he said that this is not anything new. More>>

ALSO:

Press Conference: ANZAC PMs Concerned About ISIL Bringing The War Home

Prime Minister Key and Prime Minister Abbott spoke of the bond formed between Australia and New Zealand in the “baptism of fire” of Gallipoli. Abbott stated that New Zealand and Australia’s values and interests are linked, and this is reflected in the joint operation in Iraq which will begin shortly. More>>

ALSO:

Get More From Scoop

 

LATEST HEADLINES

 
 
 
 
 
 
 
 
 
Regional
Search Scoop  
 
 
Powered by Vodafone
NZ independent news