Phosphorus capture, immobilization and channeling through algae for a sustainable agriculture

Abstract

Excessive use of phosphorus (P) based fertilizers for improved agricultural productivity has resulted in nutrient enrichment and consequent deterioration of surface and ground waters. Naturally, available soil microbes in an agricultural set-up are capable of mineralization of organic P and/or solubilisation of inorganic P thus making it bioavailable to the crop systems. As an alternative to conventional P based fertilizers, wastewater rich in nutrients can be cheap and economic P sources ensuring phosphorous recycle and reuse. However, the treatment of these waters to check pathogens, heavy metals and other toxicants; conveyance and storage are practical constraints that limits the usage of wastewaters directly to croplands. Wastewater grown algae as proficient biofertilizer can be potentially used to immobilize P and channelize P to croplands. Such algal biomass abundantly growing in natural waters as well as in treatment ponds can be rich sources of nutrients due to their higher P uptake abilities, growth rate and productivity. Although there are huge opportunities for using algae as a bio-filter to recover P from wastewater streams. However, their use for tapping valuable P with present day technologies are still evolving and are in infancy. Efforts on understanding the mechanism of P uptake, immobilization in algal cells and subsequent P transport to agricultural soil systems are important. This can provide global solutions in stocking wastewater P and its sustainable reuse as algal-based P rich biofertilizer.