Plant releases many bioactive chemicals from its various parts such as leaves, stem, root and
sometimes decomposed body through different mechanism into its surrounding environment.
These bioactive chemicals are often termed as allelochemicals because they interact with the surrounding
environment. This interaction is either positive or negative. Effects of allelochemicals to
the agricultural and biological ecosystem are well documented. In leguminosae family many species
are involved in releasing of allelochemicals. Many researchers found that this allelochemicals
have both positive and detrimental effects on the successive legume crops. Legume monoculture is
common in many parts of the world where they cause a numbers of ecological and economic
problems such as decline in crop yield due to soil sickness, regeneration failure and replant problem.
These negative effects of allelochemicals open a great concern on allelopathy research. This
article reviews the adverse effects of allelochemicals, their extraction and isolation, mechanism
inside the plant body. These all are done to find out the possible selection methods of succeeding
crops to avoid the allelopathic effects in the next crop of a monoculture farm field. The main purpose
of this article is to highlight the adverse allelopathic effects of legume crops to provide ways
for sustainable development in agro-ecosystem.