Phosphorus Mobilization Strategies of Grain Legumes: An Overview

Abstract

Phosphorus (P) is an indispensable element that may limit the agricultural production in the
next millennium. Though, chemical P fertilizers are the widely used source to provide nutrition to the crop plants
but depleting rock phosphate reserves, expected higher consumption, high cost of chemical P fertilizer, poor
phosphorus use efficiency, adverse effect of excessive use of P fertilizer on soil health and microbial diversity,
necessitate the need to adopt sustainable and environment friendly agricultural practices that maximize the crop
yield by improving existing use efficiency of soil phosphorus. Organic exudates of soil microbes and roots of
grain legume crops can mobilize phosphorus from unavailable soil-P pool and increase its availability for Pinefficient plant species grown in intercropping or crop rotation. Legume crops adopt different strategies such
as development of cluster roots, exudation of carboxylates, protons and acid phsophatase to render the P
available from inorganic and organic P sources. Thus, intercropping or crop rotation of cereal crops with such
legumes that have improved mechanisms to gain access to this fixed P will contribute toward more sustainable
agriculture. This review summarizes the P acquisition mechanisms adopted by specific legume crops for improving P nutrition of less P-efficient crops grown in rotation and/or intercropping as well as effect of soil
properties and global warming on this trait.