Rotorua trial examines effects of nitrogen fertiliser use on pastures and nitrogen leaching

Key findings: • Pasture response to N fertiliser was lower in the drought year 2012/2013 (7 versus 15 kg DM/kg N) • No deterioration in grass species occurred when N fertiliser was withheld over 2 years • N leaching varied between years. It was highest after the drought year, when N fertiliser was applied before and after the drought, and when grazing and N fertiliser use was followed by high drainage • N leaching under regular N fertiliser use (140-160 kg N/ha/year) was 2-5 times that under nil N fertiliser use