Allelopathy assessment of several edible crops for controlling goosegrass, Eleusine indica (L.) Gaerth

Abstract

A study was undertaken to examine allelopathic effect of chilli, rice and okra extracts on germination and growth of Eleusine indica under laboratory environments besides studying the allelopathic effect of crop residue-applied sterilized and non-sterilized soil on growth of E. indica under greenhouse conditions. The most phytotoxic extract were chilli leave, followed by chilli stem which fully inhibited the seed germination at 20 and 30 g L·', respectively. Chilli leave and chilli stem extracts inhibited the seedling growth but the okra pod and rice straw-plus-leave extracts had no effect on seedling growth under laboratory conditions. The chilli stem and chilli leave extracts had equally high allelopathic effects which caused growth inhibition to 38.2 and 54.6 %, respectively. The crop residues showed less allelopathic effects on seedling height except the seedlings treated with okra pod residue and grown using sterilized soil. The height of weed seedling was significantly reduced to 69.3 % by okra pod residue at 1.0 ton ha·1, while the seedling fresh weight was reduced by 60.2 % in comparison to control. The fresh weights of rice straw-plus-leave applied seedlings that grown using sterilized soil and seedlings of all treatments that were grown using non-sterilized soil were stimulated as the concentrations of crop residues increased, with the fresh weights of rice straw-plus-leave and chilli leave residues applied seedlings being increased by 41.5% and 69.4 %, respectively. This study suggests that all the crops extracts and crops residues exhibit the allelopathic effects on germination and seedling growth of E. indica depending on seedling age, duration of residues decomposition, compounds presence and the soil conditions. However, only chilli extract and okra residue show potent herbicidal activity.