Nitrogen as an aid to pasture establishment and renovation in Northland

Abstract

Abstract The use of urea and two slow release nitrogen fertilisers to manipulate pasture botanical composition and increase dry matter production after pasture establishment or renovation was investigated in 5 trials in Northland, New Zealand. Seven bimonthly applications of urea (50 kg N/ha/application) after pasture establishment on an undeveloped podzol increased dry matter production by 41%. The percent legume in pasture was reduced by nitrogen, but returned to a level similar to control when applications of nitrogen ceased. Lotus pedunculatus L. was a useful colonising plant for acid podzols, providing a more rapid ground cover and higher early dry matter production than Trifolium repens L. but it did not persist under the grazing regime used. Nitrogen fertiliser applied during pasture renovation increased dry matter production, nitrogen applied 2 weeks after pasture emergence producing the largest dry matter response of the single applications investigated. Multiple 50 kg N/ha applications were supe...