Abstract

This experiment was a 3 × 3 × 2 factorial laid out in a randomized complete block design and was replicated three times. Treatments comprised three sward types (pure grass, pure legume and grass/legume mixed swards), three cutting regimes (4, 8 and 12 weeks) and two nitrogen fertilizer rates (0 and 300 kg N ha^-1). Tiller density per m^-2 was increased (P < 0.05) with increase in cutting frequency and with fertilizer-N application. Tiller number per m^-2 was higher (P < 0.05) in pure grass sward compared with where grass was in mixture with legume in 2007. Increasing cutting interval from 4 to 12 weeks reduced (P < 0.05) the proportion of leaf fraction from 55 to 40% in 2006. The stem fraction was increased (P < 0.05) from 32 to 42%, while the proportion of inflorescence was increased from 13 to 15% when the interval between cuts was increased from 4 to 8 weeks but decreased later at 12 weeks. The proportion of leaf fraction decreased significantly (P < 0.05) from 49 to 43% with fertilizer-N application compared with the control in 2006. The proportion of inflorescence in the total herbage dry matter was, however, increased (P < 0.05) from 11 to 14% with fertilizer application compared with the control in 2006. Type of sward treatment did not influence the proportions of crop fractions in both years.

Key words: Type of sward, cutting interval, nitrogen application, plant parts.