Biomass productivity and carrying capacity of the natural grassland on the Accra Plains of Ghana

Abstract

The study assessed the biomass productivity and then estimated the carrying capacity of the natural grassland on the Accra Plains of Ghana between January 1990 and February 1992. Eleven sampling sites with varying grass association, soil type and ease of accessibility were sampled. In each sampling site an area of 5.0 m W 5.0 m was demarcated within which 1.0 m W 1.0 m quadrat was sampled. Sampling was done by clipping the herbage at 5 cm above ground. This was later dried at 70 oC for more than 48 h for dry matter determination. Crop growth rate was then estimated. Overall dry matter yield was 4.80 t ha-1 yr-1. It was 4.667 and 5.03 t ha-1 yr-1 on the clayey and sandy soils respectively. Three periods of crop growth rate were observed. These were i) period of very high productivity (April-July) with values of 2.128 and 2.286 of g m-2 day-1 for clayey and sandy soils respectively; ii) period of moderately high productivity (October-February) where the growth rate averaged 1.179 and 1.213 g m-2 day-1 for clayey and sandy soils and iii) periods of at least crop growth rate (March and September) with value of 0.635 and 0.749 g m-2 day-1 for clayey and sandy soils. The overall average carrying capacity was 3.60 ha AU-1 yr-1.


(Ghana Journal of Agricultural Science, 1996, 29(2): 107-114)