Abstract

Six weed management
strategies were established in with banana plantation; in San
Pablo, a farm located in the Atlantic region of Costa Rica.
Since then, earthworm counts have been performed at regular
intervals. Weed management strategies consisted of: 1-
unweeded control. 2- Hand weeded control at monthly
intervals. 3- Glyphosate (Ranger Plus-680 g/kg; at 0.687%
w/v) applications at eight week intervals. 4- Paraquat
(Gramoxone-200 g/l, at 0.75% v/v) at monthly intervals. 5-
Glufosinate (Finale-150 g/l, at 1% v/v) applications at eight
week intervals. 6- Monitored treatment, depending on
detected weeds, only in the area of maximum weed-crop
interference. Earthworms were counted, at each sampling
time, from four 15625 cm3 soil samples of each plot. Samples
were taken from different microhabitats, including soil
covered with Paspalum conjugatum; soil covered with
Panicum zizanoides; soil covered with banana residues
(leaves, pseudo-stems) and bare soil. Soil samples from sites
covered with banana residues or Paspalum conjugatum
showed the highest earthworm counts, followed by soil
covered with Panicum zizanoides and bare soil. A direct
effect of weed management strategies on earthworm number
has not been detected.