Effect of soil texture on phytotoxicity of an invasive weed, Ageratum conyzoides L.
A study was conducted to explore the influence of soil texture on the phytotoxic potential of Ageratum conyzoides. Effect of five different types of soils i.e. clay only, sand only, loam, sandy loam and clayey loam was studied using amendment of A. conyzoides leaf powder (1 and 2 g/100 g soil) with separate control of each type against seedling length and dry weight of Oryza sativa. It was observed that greatest inhibition in seedling growth occurred in sandy soils, while it was minimum in clay soil. The amended soils were not poor in nutrients, rather these contained a significant amount of phenolics, water soluble allelochemicals. The inhibition in seedling growth was directly related to the amount of phenolics in the soils. The maximum content of phenolics was observed in sandy soils while minimum in clay. The study concludes that phytotoxicity of A. conyzoides is greatly influenced by soil texture and it enhances in sandy soils.