Effect of nitrogen and cutting interval on production of grass species swards in Northland, New Zealand

Abstract

Abstract The effects of 2-, 4-, and 6-weekly cutting intervals and 4 rates of nitrogen (0, 120, 240, and 480 kg N/ha/year) were examined on kikuyu (Pennisetum clandestinum Hochst ex Chiov.)-dominant swards at three locations in Northland from January 1971 to December 1972. Sward production was generally highest in autumn when moisture was adequate and mean temperatures were still high. At other times low temperatures and/or moisture stress limited dry matter production. From April to August monthly pasture production was strongly correlated with temperature variables, and for every 1°C decline in daily grass minimum temperature, pasture production decreased by 3.4 ± 0.4 kg DM/ha/day. Nitrogen increased annual DM yield at each site, the response being generally linear. At each site the effect of nitrogen was greatest during the winter and spring, when Poa species made a large contribution to DM production, and in autumn, when swards were kikuyu dominant. Extending the cutting interval increased DM yields, ...