Effect of harvesting interval and n-fertilizer application on the gross energy, digestibility and crude fibre content of field swards

Abstract

Effects of four levels of N-fertilizer application and six internals between harvests on field swards of Northern gamba grass, (Andropogon gayanus), Guinea grass c.v.s112, (Panicum maximum) and star grass (Cynodon Polystachyus) were studied over 30 weeks period in 1986. There was a significant (P<0.05) increase in gross energy (GE) content by increasing N application and much more increase by increasing interval between harvests. For the three species, highest GE/kgN applied was obtained with 150kgN/ha-1 than with 0kgN/ha/yr or 450kgN/ha/yr. Harvesting frequencies and N application exerted a significant effect on the digestible organic matter (D-value). This study has established that the stage of growth in field swards has great influence on D-value and the main scope of improving the D-value would be to harvest every 4, 5 and 6 weeks for star grass, guinea grass and northern gamba grass respectively. The crude fibre content of herbage was increased by increasing interval between harvests but dropped consistently for every unit of 150kgN/ha-1 applied.

Keywords: nitrogen fertilizer, harvest intervals, gross energy, digestibility and fibre or field swards

Global Journal of Agricultural Sciences Vol. 4(2) 2005: 173-176