Allelochemical effect of Ageratum conyzoides L. leaf extract on Soybean [Glycine max (L.) Merr. cv Grobogan] growth

Abstract

Soybean [Glycine max (L.) Merr. cv Grobogan] is one of the most important commodities in Indonesia, but its production is often decreasing due to weed disturbance. One type of weed that has an allelopathic effect is A. conyzoides. Allelopathy is a phenomenon of plant releasing a chemical exudate into the environment that can suppress the growth of other plants. This study aims to determine the total phenolic content of A. conyzoides and examine the effect of the A. conyzoides allelochemical extract against the growth of soybean. The experiment was performed in completely randomized design (CRD) with one factor of concentration of a allelochemical extract of A. conyzoides. Each treatment has five replications. Treatments with different concentrations, i.e., 0%, 5%, 10%, 15% and 20%. The parameters measured were the plant height, wet weight, dry weight, chlorophyll a, chlorophyll b and total chlorophyll were analyzed by Analys of Variance (ANOVA) followed by Duncan’s Multiple Range Test (DMRT) at the level of 95%. Total phenols contained in extract of A. conyzoides leaf is 16.121 μg GAE/g. The results showed that the higher the concentration of the allelochemical of A. conyzoides leaf extract reducing plant height, wet weight, dry weight, growth tolerance index (GTI), chlorophyll a, chlorophyll b and total chlorophyll.