Influence of harvesting management and nitrogen fertilizer application on plant fractions in field swards

Abstract

An investigation to determine the influence of harvesting management and nitrogen (N) fertilizer application on plant fractions of Northern gamba (Ngg), guinea grass S112 (Gg) and star grass (Sg) was conducted at the University of Nigeria, Nsukka in 1985 and 1986 wet seasons. The experiment comprised all possible combinations of the three grass species and four N fertilizer levels: (0, 150, 300 and 450 Kg N ha^-1) and six harvesting intervals (3, 4, 5, 6, 8, and 10 weeks) and was laid out as a 3 x 4 x 6 split – split – plot in a randomized complete block design, replicated three times.


Nitrogen fertilizer and harvesting management exerted significant effects on plant fractions of each species. Species differences, and differences due to N supply and harvesting management on stem, green and dead leaves, and inflorescence fractions were significant (P < 0.05). Extending the interval between harvests from 3 to 10 – weekly cuts significantly reduced the proportion of green leaves and increased the proportion of dead leaves and stem in the three species during the two study periods. There was a 183.1% (18.1 – 6.5) unit drop in green leaves in 1985 and 200% (16.8 – 5.6) unit drop in 1986 when cutting intervals increased, on the average from a 3, 4 and 5 weeks to a 6, 8 and 10 weeks. The application of N increased the numbers of leaf primordial per tiller delayed flowering in Ngg and reduced flowering in Gg. Delaying cutting reduced the proportion of green leaf blade but increased that of ‘stem'. These results are discussed in relation to management of the sward during the growing season.


KEY WORDS: Harvesting Management, Nitrogen fertilizer and plant fractions in field swards.


Global Jnl Pure and Applied Sciences Vol.10(4) 2004: 535-543