A continuous sampling technique to estimate surface cast production of the tropical earthworm Hyperiodrilus africanus uri icon


  • Cast destruction by rain was estimated to be 21.7%. The difference between amounts of casts recovered under permanent protection from rain and from plots exposed to full impact of rain was not significant. There was no correlation between the amount of cast material detached by rain and the amount of rain fallen between samplings.
  • Shading increased casting activity by up to 88%. Significant shading effects occurred at a light interception of 24% and above. The continuous removal of casts did not significantly change casting activity. Average casting dropped by 0.28 Mg ha(-1) or 2.25% when casts were removed.
  • Surface casting activity of the tropical earthworm Hyperiodrilus africanus was monitored for 140 days during the rainy season on an Alfisol manually cleared from bush regrowth. Casts were collected once per week from areas with different levels of shade. After dry matter determination, casts were either returned or not returned to the sampled area to assess changes in casting activity as a consequence of cast removal. To assess the proportion of casts destroyed by rain between samplings, in a second experiment, the soil surface was either protected by screen or cotton cloth from direct impact of rain or left open for full impact of rain.
  • The continuous sampling technique, used to assess the contribution of earthworms to nutrient cycling, top soil formation and soil organic matter dynamics, can produce valid data without significant disturbance to the system. (C) 1998 Elsevier Science B.V.

publication date

  • 1998
  • 1998