News & Advice

From 1 July 2026, new regulatory requirements will apply to Ravensdown's urease inhibitor products N-Protect and Flexi-N (NBPT). These changes are the result of updated Government regulations and affect how these products are used on pasture. 

While the changes introduce new application and grazing requirements, farmers can continue to use these products with confidence. The practical impact is largely around planning grazing rotations and ensuring treated paddocks are not grazed immediately after application which follows good agricultural practice for fertiliser use. 

What's changing?

N-Protect and Flexi-N (NBPT) are now registered under New Zealand's Agricultural Compounds and Veterinary Medicines (ACVM) Act. 

This follows a 2022 regulatory change that brought urease inhibitors under the same registration framework used for agricultural chemicals. As a result, these products are now subject to specific label conditions that did not previously apply. 

For pasture use, the new requirements include: 

• a maximum single application rate of 100 kg product/ha (46 kg N/ha)
• a three-day withholding period before stock can graze treated pasture
• product expiry dates in relation to how long product should be stored in a Ravensdown store or on farm before use. 

What does the grazing withholding period mean?

Mike White, Ravensdown Chief Scientist, says the most significant change for many farmers will be the introduction of a three-day withholding period after applying N-Protect or Flexi-N (NBPT) to pasture. 

“The three-day withholding requirement is based on a precautionary approach relating to potential animal exposure to urea granules rather than concerns about NBPT residues. For this reason, Ravensdown also recommends applying the same good practice to standard urea applications, ensuring stock are excluded until fertiliser granules have dissolved or are no longer visible. 

“Farmers who routinely apply urea products immediately before grazing may need to adjust grazing plans and application timing to accommodate the three-day stand-down period.” 

There are no prescribed maximum application rates or withholding periods for N-Protect or Flexi-N (NBPT) when used on crops. Instead, growers should work with their Ravensdown agri manager or agronomist to determine the most appropriate application programme for their crop and farming system. 

New expiry date requirements

The registrations also introduce expiry date requirements. 
NBPT naturally degrades over time, so Ravensdown has implemented systems to track product age and ensure performance is maintained. 

Products should be used within the following periods after being dispatched: 

• N-Protect: within four weeks
• Flexi-N (NBPT): within two weeks. 

Your Ravensdown representative can provide advice on product handling and storage to ensure product quality is maintained.  

No change to N-Protect and Flexi-N efficacy

N-Protect and Flexi-N (NBPT) remain valuable tools for improving nitrogen efficiency and reducing nitrogen losses. 

While the regulatory requirements have changed, the products themselves have not. Ravensdown remains committed to providing farmers and growers with practical advice and support to ensure these products continue delivering value within the new regulatory framework.

For more information, please contact your Ravensdown agri manager or agronomist.