Grassroots science holds key to sustainable farming

Converting from pines to pasture has been an environmental balancing act for Nga ¯ i Tahu’s Paritea Farm in North Canterbury.

Having used large amounts of nitrogen to break down carbon in the soil, Nga ¯ i Tahu is now looking at scientifically- proven ways to reduce nitrogen use as part of DairyNZ’s Forages for Reduced Nitrate Leaching research programme.

When Shane Kelly joined Nga ¯ i Tahu Farming as rural project manager in 2013, his job was to oversee the conversion of 3900ha of forestry land to irrigated pasture.

Keen to apply the latest science- backed farming practices, he and the iwi quickly put their hands up to take part in the Forages for Reduced Nitrate Leaching ( FRNL) research programme.

FRNL is a six- year DairyNZ- led programme looking at how to target different aspects of the nitrogen ( N) cycle to reduce nitrate leaching. These include reducing the N content of animals’ diets, altering urinary N excretion, and increasing N uptake by pasture or crops.

‘‘ Becoming part of the FRNL research project in 2014 was an opportunity for Nga ¯ i Tahu to implement best practice and integrate the research findings into its dairying business,’’ says Shane, who is now Nga ¯ i Tahu Farming’s general manager of dairying.

‘‘ Because Paritea Farm is on ex- forestry soils, it historically used significant amounts of nitrogen to assist with carbon breakdown, so in this context, it’s very important for us to explore good research.’’

Paritea Farm is part of the Nga ¯ i Tahu Te Whenua Hou farming development north of Christchurch and is one of nine monitor farms in Canterbury contributing to the FRNL research project.

The monitor farm network includes a mix of dairy, arable, sheep and beef, and mixed arable/ dairy properties.

Farmers and scientists work together to put theory into practice and monitor the results.

So far the FRNL research has identified three promising options – the use of plantain, fodder beet and a catch crop – that significantly reduce nitrate leaching.

Paritea farm manager Sam Lovelock, Nga ¯ i Tahu Farming’s general manager of dairying Shane Kelly and staff member James Keeling: using fodder beet to transition into winter, followed by oats to capture nitrogen left in the soil.

FRNL research has shown that, when managed properly, fodder beet can lower animals’ N intakes and urinary N excretion without negatively affecting their health and productivity.