EFFECT OF LEAF EXTRACTS OF Swietenia mahagoni L. ON THREE AGRICULTURAL CROPS

Abstract

A study was conducted at the Department of Agroforestry and Environment, Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh during May to September 2018.There were two experiments in the study. Experiment one was conducted to find out the effect of leaf extracts of Swietenia mahagoni on the three agricultural crops in laboratory condition. There were three concentrations of leaf extracts viz., 1%, 2%, 3% along with a control (only water). Experiment two was conducted with 1%, 2%, 3% concentration of leaf extracts with control (only water) in the pot. In both experiments, three agricultural crops namely Chilli, (Capcicum annum), Brinjal (Solanum melangona) and Okra (Abelomoschus esculentas) were taken as test crops to satisfy the objectives of the study. Designs of laboratory and pot experiments were CRD with three replications. Results of laboratory experiment showed that 3% concentration of leaf extracts of S. mahagoni inhibited more germination of all the three tested crops compared to other concentrations. Three percentage concentrations leaf extracts of Swietenia mahagoni showed that the germination percentage were 59.10% in Chilli, 56.28% in Brinjal, and 49.20% in Okra over control. The results indicated that inhibition increases with the increase of concentration. In case of pot experiments, leaf extracts of S. mahagoni also inhibited the germination of the three tested crop. Three percentage concentrations leaf extracts of Swietenia mahagoni showed germination percentage 55.69% in Chilli, 48.26% in Brinjal, and 50.23% in Okra over control. Morphological parameters like plant height (cm) showed significantly better performance in control over leaf extracts in all the tested crops at both laboratory and pot experiments. Similar results were recorded for biomass allocation like total dry weight (g). Among the three tested crops, Chilli performed the best compared to other two crops. From the overall result it can be concluded that the allelopathic effect of leaf and root of S. mahagoni on the agricultural crops which inhibited more in laboratory compared to pot condition. This effect may be minimized through proper management of the agroforestry field by removing the fallen leaf residues.