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

EPA: Board Of Inquiry Rejects Basin Flyover By Majority Of 3 To 1

The independent Board of Inquiry delegated to decide on the Basin Bridge Proposal has, by a majority decision (3 to 1), cancelled the Transport Agency’s Notice of Requirement and declined its resource consent applications for the construction, operation and maintenance of a flyover on State Highway 1 in Wellington City between Paterson Street and Buckle Street/Taranaki Street...

Parties specified under Section 149Q(3) of the RMA now have 20 working days to make comments on minor or technical aspects of the report. More>>

 

Parliament Today:

Red Tape: Local Regulations Go Under Microscope

The Government says it is accepting nearly all of the recommendations the Productivity Commission has made on ways to improve local regulations. More>>

ALSO:

Spending Questions: Claudette Hauiti To Step Aside At Election

National Party President Peter Goodfellow confirms that he has received notification from List MP Claudette Hauiti that she plans to step aside at the 20 September election. More>>

ALSO:

Gordon Campbell: On The Non-Apology To Tania Billingsley

The refusal by Prime Minister John Key to issue a personal apology to Tania Billingsley has been accompanied by an array of excuses... Yesterday though, Key’s choice of words indicated that an apology was the last thing on his mind. More>>

ALSO:

Conventions: Winston Peters On The Nation

Winston Peters opens door to standing in East Coast Bays electorate, says it's an "exciting point" and he's thinking about it. "I’ve had a whole lot of people writing to me and calling up and saying ‘why don’t you have a go in East Coast Bays’." More>>

ALSO:

Waitangi Tribunal: Report On The MV Rena

In its interim report, the Waitangi Tribunal has found that the Crown’s conduct in response to the grounding of the MV Rena on Otaiti (Astrolabe) reef breached the principles of the Treaty of Waitangi. More>>

ALSO:

Gaza: Wellington Protest For Palestine Calls For End To Bombing

Around 300 people gathered outside the Israeli Embassy in Wellington on Friday to protest Israel’s occupation of Palestine. More>>

ALSO:

Gordon Campbell: On The Failure To Prosecute The GCSB

So one hand of the state – the Independent Police Conduct Authority – has now washed the hands of its brother agencies, and declared that all hands are clean. Case closed. More>>

ALSO:

Illegal Search: Police Behaviour 'Reminiscent Of Tūhoe Raids'

"Māori will lose further trust and confidence in the New Zealand Police and the Independent Police Conduct Authority (IPCA) if the recent incident in Stratford is not adequately addressed. This behaviour would not occur in Epsom or Khandallah so why should police think that such behaviour was acceptable in Stratford," says Chris McKenzie. More>>

ALSO:

Get More From Scoop

 

LATEST HEADLINES

 
 
 
 
 
 
Regional
Search Scoop  
 
 
Powered by Vodafone
NZ independent news