• Abstract

•  ashis78@rediffmail.com

Sustainable production of horticultural crops in the tropics is often severely constrained by the fragility of soils, being prone to several forms of degradation. Microbes being an integral component of any soil eco-system provide life to the soil. They render soil richness in terms of making available slow-release nutrients, continuous breaking down of complex macro-molecules and natural products into simpler one to enrich beneficial substances, maintaining good physicochemical properties of the soil and most essentially providing support to the plants in terms of growth enhancement. This review treats the role of microorganisms in improving nutrition of major (N, P and K) as well as micronutrients in horticultural crops, promoting plant growth and yield. It focuses on the mechanisms of various groups of microorganisms involved in harnessing atmospheric N₂, mobilizing insoluble source of phosphorus, potassium and micro-nutrients and promoting plant growth through improved nutrition and growth hormone production. Further improvement in the efficiency of phosphate mobilizing micro-organisms through genetic engineering has also been discussed. Thus microbial association enable a better use of sparingly soluble nutrients either inherited from soil or applied through anthropogenic sources, thereby increasing the efficiency of added fertilizers.

Keywords :   Micro-organisms, horticultural crops, nutri­tion, plant growth promotion