Allelopathic principles for sustainable agriculture

Authors: MALLIK, M - Langston University; Williams, Robert

Submitted to: Allelopathy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/9/2009
Publication Date: 6/30/2009
Citation: Mallik, M.A., Williams, R.D. 2009. Allelopathic principles for sustainable agriculture. Allelopathy Journal. 24(1):1-34.

Interpretive Summary: It has long been recognized that some plants and microorganisms can either stimulate or inhibit growth of other plants and/or microorganisms in the surrounding area. This phenomenon is called allelopathy. For example, hairy vetch is used as a green manure crop during a fallow period in a field. This fast growing legume suppresses weed growth during the fallow period in part due to toxic chemicals exuded by its roots into the soil, as well as during decay when the crop is turned under as a green manure. In other applications microorganisms that are beneficial to plant growth are often inhibitory microorganisms that cause plant disease. By providing these microorganisms during planting we may protect the crop from attack by a plant pathogen. Some microorganisms provide growth stimulating compounds that aid in seed germination or stimulated seedling growth and establishment. Other microorganisms can supply nitrogen to the crop plants, reducing the need for chemical fertilizers. Several microorganism can be combined to make a 'biofertilizer' that is added during planting to aid in crop establishment and growth. The use of allelopathic principles in agriculture could reduce the use of chemical pesticides and fertilizers. In this review we show how these materials have been used in laboratory and field experiments, and their role is developing sustainable agricultural systems.

Technical Abstract: Allelopathic research of the past few decades has established the feasibility of weed and plant disease management by allelopathic crop plants, plant residues, cultural manipulation, and microorganisms as bioherbicides and rhizobacteria. Inconsistency in the effectiveness of plant-growth-promoting rhizobacteria (PGPR) to stimulate plant growth and yield has been reported. This inconsistency in the expected results from PGPR applications can only be remedied by improved knowledge of interplay between host and introduced PGPR inoculant in the rhizosphere. Application of biofertilizer has been demonstrated to reduce the quantity of chemical fertilizer used for maintaining threshold level of crop productivity. We hope this review will stimulate further research in a holistic approach to solve agricultural problems and achieve sustainable agriculture that is economically profitable and environmentally benign.