Chatham Rock Phosphate will help save our rivers

The use of Chatham rock phosphate by NZ farmers will improve water quality, reduce carbon emissions, slow the accumulation of cadmium in soils and offer security of supply in a volatile market.

CRP has been observing with great interest the evolving dialogue about water quality in NZ’s waterways and the escalating concerns about nitrate and phosphate run-off.

None of this is news to us.

Chatham rock phosphate, found on the Chatham Rise, has been studied and tested by New Zealand scientists and agricultural institutes for more than 50 years. These tests have established that rock phosphate from the Chatham Rise has the following characteristics:

1.      It is a reactive phosphate rock that when applied directly to the soil binds in a manner that is both a very effective fertiliser and can reduce the runoff of phosphate to waterways by up 80% less finishing in the waterways when it rains heavily. We have already released this information to shareholders and the public . We have also provided advice on this matter (together with references to the relevant research findings) to the Minister for the Environment as long ago as December 2012.

2.      Cadmium levels in many New Zealand soils are at unacceptably high levels after decades of fertiliser application using phosphate rock sourced from Nauru. Due to this NZ’s two fertiliser manufacturers have volunteered to keep cadmium levels in manufactured phosphate fertilisers under 280 parts per million.  In recent years the predominant source of rock phosphate has been rock imported from Morocco. Cadmium levels can be so high in this phosphate rock that it needs to be blended with rock imported from other countries. Chatham phosphate rock has much lower cadmium levels, about 20 parts per million and is potentially valuable as a blend for manufactured phosphate fertilisers.

3.      Reduced carbon footprint. At present every kilogram of phosphate based manufactured fertiliser applied to New Zealand soils has already generated carbon emissions of 216 grams. The equivalent emissions for Chatham Rock Phosphate are estimated to be a quarter of that, principally because the transport related emissions are so much lower.  

4.      Chatham rock phosphate applied directly to the soil contains elevated levels of calcium which plays a critical role in plant root development and nutrient uptake as well as improving the soil’s physical structure and enhancing the life cycles of microbial life. 

These attractive environmental attributes do not come at the expense of reduced fertiliser effectiveness. Extensive independent field trials in the 1980s, corroborated by recent pot trials undertaken by Lincoln University, demonstrate that Chatham Rock Phosphate is, over time, as effective a fertiliser as superphosphate or even triple superphosphate.

Not using Chatham phosphate rock as a fertiliser will cause the New Zealand environment damage that could have been avoided. This will ultimately result in either a degraded environment or huge clean-up costs.

The economic benefits of using locally sourced rock are a no-brainer. 

Our mining costs are roughly equivalent to the transport costs of bringing rock to NZ from the other side of the world. Clearly we have a huge strategic advantage in market terms without even starting to consider the indirect environmental cost savings resulting from using Chatham rock phosphate.

Enquiries on any aspect of this release are welcome.


 Chris Castle


Chatham Rock Phosphate Limited

Mobile: +64 21 558 185