Partitioning of Chemical and Physical Effects of Earthworms on Growth Performance of the Vegetable Amaranthus

This study was carried out to partition the physical and chemical effects of earthworms on the vegetable crop Amaranthus. By restricting earthworms to one half side of plant pots and comparing plant growth performance on both sides of the pots, and by comparing these with completely wormless pots (control), statistical analyses showed that plants on the wormless sides of wormed pots perform better than those in control pots. This suggests that some earthworm products cross the cloth septa to positively influence the plants on the wormless sides. The differences represents the effect due to chemical products of earthworms or of their activities. Plants on the worm sides of pots perform better than those on the wormless sides. Their difference represents the physical effects of the earthworms. It is estimated that chemical effects of the earthworms Libyodrilus violaceus improve Amaranthus performance by about 32% and the physical effects by about 36%. The total effect of both amount to about 68%. The growth parameter significantly improved are: plant height, leaf length, leaf area and number of leaves, whereas stem girth and leaf width are not significantly affected. This suggests that some chemical product of the earthworms affect primary apical meristem in the cell proliferation and elongation zones. This agrees with the suggestion that earthworms produce auxins and cytokinins. The estimated optimal level of earthworm treatment was 15 earthworms per pot (equivalent to 3.77million worms/ha, or 0.38T/ha for L. violaceus). For Amaranthus the parameters most improved by the earthworms were those that most affected market value. This should therefore be a good campaign factor to encourage farmers to adopt earthworm transplatation as a partial substitute for application of inorganic fertilizers