Phosphorus management strategies to enhance P-use efficiency and sustainable crop production

Abstract

With increase in food grain production in India from 50.8 million tonnes (Mt) in 1950-51 to 295.67 Mt in 2019-2020, the production and consumption of phosphorus (P) fertilizer has also increased from 9.8 thousand tonnes in 1950-51 to 4790 thousand tonnes in 2019-2020 and from 6.9 thousand tonnes in 1950-51 to 7464 thousand tonnes in 2019-2020, respectively (FAI 2020). Phosphorus is the second important primary nutrient element after nitrogen. Low P use efficiency is the significant challenge for agricultural production on P-deficient soil as well as in acidic and calcareous soils (Shenoy et al. 2005). Acquisition of soil and fertilizer P by crops depends on soil and plant properties. Soil processes determining P availability to plants are P solubility/sorption, P transport, root/soil contact and mineralization/ immobilization (Horst et al. 2001). Agronomic strategies for enhancing P use efficiency includes selection of fertilizer, soil test based P application, methods of P fertilizer application, fertigation, residual P utilization by different crops, utilization of insoluble P sources by addition of organic matter and phosphate solubilizing microorganisms (PSM), integrated nutrient management (Subba Rao 2010). Improved P use efficiency has been observed by Mengel (1997) in acidic soil by applying P at the time of sowing and liming. The two main strategies which help plants to improve P use efficiency are (i) root-foraging strategies that improve P acquisition; and (ii) P-mining strategies to enhance the desorption, solubilization or mineralization of P from sparingly soluble sources in soil using root exudates (Richardson et al. 2011).