Abstract:
The objectives of this study were to investigate the effect of ground cover
vegetation types and precipitation on earthworm activity and to assess the
earthworm contribution to soil porosity in green open spaces (“RTH”) at the campus of Riau University. Four different cover vegetation types were examined: grass, shrubs, single tree and compound trees. This study was conducted from
March-May 2013. Twenty observation plots of 1 m x 1 m were randomly selected to represent each cover vegetation type. The cast productions was observed every 5 days within 50 consecutive days. Precipitation data of the same period was
obtained from the Meteorological Office of Pekanbaru City. The environmental
condition in each plot was characterized based on four parameters: the ground cover vegetation, root mass, soil bulk density, and soil pH. Chemical analysis was carried out to determine C-organic, total N, P, and K as well as P-available contents of soil and cast samples. Texture analysis was also performed on soil and
cast samples. The results showed that cover vegetation type and precipitation
significantly influenced earthworm activity (P<0.05) as indicated by the amount of cast produced. Casts had significantly higher content of C-organic, total N, P, and K as well as P-available compared to soil (P<0.05). Casts also had smaller sand fraction but higher clay fraction than soil. In conclusion, the most active
earthworms, thus also enhancing soil porosity the most, were found under shrubs while the least active were found under grass as reflected in cast production level.
