Reduced soil fertiliser and chemicals for animal health can have environmental and cost benefits for farmers. Carbon emissions and nitrogen pollution are reduced and spending on animal remedies is saved.
Respected former Ruakura scientist Dr Clive Dalton has reported that our highly efficient conversion of grass to animal products has been eroded over the years by increased use of nitrogen fertilisers. The advent of the Kapuni ammonia urea plant in Taranaki in the 1980s had urea fertiliser applications more than double, particularly in the dairy industry. Clover that naturally fixes atmospheric nitrogen started to disappear in mixed pastures, leaving them grass dominant and nitrogen hungry.
The downsides have been mainly environmental, with increased nitrogen runoff polluting our waterways and nitrous oxides from soil and fertilisers increasing potent greenhouse gas emissions.
These trends have affected how Stuart Pritchard farms near Ōtaki. He’s a firm believer that low input farming – with less nitrogen fertiliser and organic farming principles – are the way to go.
Stuart’s wide previous experience includes dairying, large-scale bull beef, cash cropping, horticulture and property development. He is currently registered with an AssureQuality organic farming “conversion” status.
About 35 crossbred heifers come onto his 15-hectare property in August each year as 185kg weaners. They’re efficiently grown to 500kg as two-year-olds.
High pH, slow-release rock phosphate and lime fertiliser, the basis of his “functional fertilisers”, ensure pastures are lush and highly nutritious. Clover content is high with a ryegrass base, and mixed with dock, plantain and buttercup, provide great diet satisfaction for the cattle. Based on regular soil tests, essential minerals are added to fertiliser as needed and sulphate of potash is applied in summer.
With the above fertiliser regime, Stuart’s mantra that “clover is king” is a reality, his cattle efficiently cleaning up the flourishing mixed pasture with high growth performance and outstanding meat quality.
The cattle are quarantined on arrival at the property and receive no chemical treatments thereafter.
Stuart rotationally grazes his cattle with 48-day intervals in winter reducing to 20 days during the spring pasture growth flush. Grazing pressure is light, going from 4000kg DM per hectare to about 1500kg with grass, clover and herbs all eagerly consumed by the cattle. From 18 tonnes of dry matter per hectare grown annually, surplus pasture goes into about 120 bales of baleage for winter feeding.
Complementary sidelines on Stuart’s property include a four-hectare block of native trees to help mitigate greenhouse gas emissions, and a bee-breeding enterprise for export of queen bees and production of organic honey.
Graham Shepherd of Bioagrinomics says the greenhouse gas emissions index on Stuart’s farm is relatively low and environmentally friendly.
Minimal fertiliser use not only makes a major contribution to New Zealand’s long-term goal of carbon neutrality by 2050, but also contributes greatly to less nitrogen pollution of waterways, avoiding compromise of valuable biodiversity. Low use of chemicals for animal health reduces input costs and is essential for organic farming. All these low-input measures help greatly with product quality and marketing.
Dr Ken Geenty has had a 30-year research and development career in the New Zealand sheep and beef cattle industry, including pioneering research in sheep dairy production. He now lives in Ōtaki.