Phosphate Solubilizing Microbes: A Biological Solution for ‘P’ Nutrition in Sustainable Agriculture

Abstract

The global demand to enhance agricultural productivity from a steadily decreasing and degrading land resource base is a major strain on agro ecosystems. Current strategy to maintain agricultural productivity is exclusively through inputs of costly chemical fertilizers. Although the use of chemical fertilizers is credited with nearly fifty percent increment in agricultural production but their adverse effects on soil health and environment necessitate the need to adopt sustainable and environment friendly approaches. In sustainable production systems, replenishment of soil nutrients especially phosphorus is a major challenge as it is mainly fertilizer dependent. Phosphorus fixation and precipitation cause its deficiency for plant development and in turn restricts the crop growth. To circumvent the soil P deficiency, an alternative, inexpensive technology in the form of phosphate solubilising microorganism could be exploited while reducing the dependence on expensive chemical P fertilizers. The phosphate solubilizing microorganisms (PSM) inhabiting diverse ecological niche not only function as P provider to plants through inorganic/organic phosphate solubilisation/mineralization processes but also facilitate plant growth by N2 fixation, enhance availability of other plant nutrients, synthesize phyto-hormones, suppress plant diseases (bio-control) and reduce the toxicity of ethylene through 1- aminocyclopropane-1carboxylate (ACC) deaminase. The challenge is how to make best use of such biological resources to increase the crop productivity. In this chapter, attention is paid to the effective use of phosphate solubilizers for improving plant growth through decreased application of chemical fertilizers.