A Whangarei lime quarry is investing in the growing interest among Northland farmers in low input farming – a farm management approach that seeks to reduce fertiliser application rates and costs, while maintaining farm profits and production levels.

Recently, Avoca Lime Company Ltd began production of dicalcic phosphate, a fertiliser made from a combination of wet lime and mature superphosphate that significantly reduces both the cost of fertilizer and the level of nitrogen added to pastures.

Bryce Manderson runs Avoca Lime, a family business which has been in operation for over 60 years.  He says dicalcic phosphate is a well-rounded environmental product with huge potential in the local area.

“There’s a lot of interest building in this product, driven by the push to reduce farm costs and the increased pressure on farmers regarding environmental compliance.  Dicalcic phosphate hits both those targets – low cost application and minimal levels of run off and leaching,” he says.

Dicalcic phosphate was developed in Hawke’s Bay by the Hatuma Lime Company in the 1960s and has slowly built a dedicated following throughout the lower North Island. Recently, increased cost pressures on farmers and concerns about nitrogen leaching into waterways has spiked interest in the product as farmers have looked to find ways to maintain production levels with lower inputs than have traditionally been seen as optimal.

John Woods owns Mangaroa Farms, a sheep and cattle operation 30 kilometers northeast of Whangarei.  He has used dicalcic for four years and says it saves him both time and money.

“Here in the hill country run off is fact of life, especially after heavy rain.  Because dicalcic is less soluble, it sticks around longer, releasing phosphate that would otherwise stay locked up in the soil.  We’ve had some really wet winters in recent years so the dicalcic has been really indispensible.”

He also says lower nutrient inputs are particularly welcome in the face of tough economic conditions.

“Another thing about hill country farming is that you need planes for each application.  The cost can get up there if you’re looking at separate applications of lime and phosphate, so it’s a no brainer to use a product that is the best of both worlds,” Mr Woods says.

Scientific studies on dicalcic farms have shown some surprising results in terms of soil quality and stocking numbers.

Jon Manhire from The AgriBusiness Group is heading a research project which is examining the impacts of dicalcic on soil and pasture quality as well as production and bottom lines.

“It’s early days in our research programme but the results so far are encouraging. We’re seeing farmers putting less phosphate onto their pastures and maintaining higher stocking rates than their regional averages.  This is encouraging in an era when farmers are having to find ways to cut costs and reduce their impact on the environment.”

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