*Sustainable Management of Phosphorus in Agriculture for Environmental Conservation DOI: http://dx.doi.org/10.5772/intechopen.113086*

Therefore, agricultural management practices should focus on reducing P-transport caused by excessive consumption of inorganic fertilizers and organic manures [67]. Both soil and hydrological factors are responsible for the movements of P [68]. The former decides the initial transport, while the latter is associated with transport as well as the pathways. There are three major pathways by which P is transported to surface water bodies. Those are surface runoff, subsurface flow, and vertical flow [67]. Minimizing soluble P concentrations or increasing water infiltration in soil for P-adsorption will help in decreasing the dissolved P-transport [69]. The subsurface flow of P is a concern only for soils having high P-saturation or preferential flow. At high rainfall intensity (hydrological factor), fertilizers containing a higher concentration of water-soluble P can increase P-transport in runoff [70]. Manures containing high organic P (like poultry manure) may contribute to dissolved P-losses via leaching and displacement of loosely bound inorganic P [71, 72]. The possible transport of P in the environment has been highlighted in **Table 1**.

Long-term application of P-fertilizers (like triple superphosphate) may increase the concentrations of some trace elements or heavy metals (arsenic, cadmium, copper, chromium, nickel, vanadium, and zinc) in soil [73]. Mining and processing of rock phosphate cause significant contamination (from radioactive to heavy metal pollutants) in the environment [74, 75]. Phosphogypsum, a by-product obtained during the processing of rock phosphate, marks a serious potential hazard for human health and soils, water, and atmospheric pollution [75]. The use of organic wastes (pig slurry and cattle slurry) above crop P demands saturates soil adsorption sites, leading to P-migration in the soil profile and subsurface water contamination [76]. Therefore, instead of the bulk application of the bioresources, technologies should be framed to recover P from human and animal wastes including sewage, sludge, manure, incineration ashes, etc., by developing contaminant-free fertilizers, e.g., struvite (ammonium magnesium phosphate) and/or other soluble products for efficient P-cycling [77].


#### **Table 1.**

*Transport of phosphorus in the environment.*
