Inhibitory effect of some crop residue water extracts on germination and seedling growth of sickle pod (Senna obtusifolia (L.) Irwin and Barneby).

Abstract

One major interest of modern agriculture is to reduce the use of herbicide by identifying and developing safe alternative to herbicide for weed control. Water extracts (at concentrations of 5 and 10 %) of ‘egusi’ melon, rice and maize husk were used to determine their inhibitory effects on the germination and seedling growth of sicklepod (Senna obtusifolia (L.) Irwin and Barneby. It was apparent that maize husk water extracts had more inhibitory effects than ‘egusi’ melon and rice husk water extracts on germination, root and shoot growth as well as seedling dry weight. Maize water extract at 10 % reduced the germination of sicklepod by 81.2 %. It also significantly (P > 0.05) suppressed root and shoot length as well as seedling dry weight of sicklepod by 83.3 % and 82.1 % as well as 85.7 % respectively. All the seedling growth parameters including germination percentage decreased significantly (P > 0.05) with increasing level of maize extract concentration compared with the other extracts and control. Shoot length (r = 0.835), root length (r = 0.831) and seedling dry weight (r = 0.833) positively correlated with germination percentage. Root length exhibited the strongest morphological character for allelopathic assessment of sicklepod seedlings.