Phosphorus Transport in Nano Rockphosphate Treated Soils

The excessive usage the phosphorous (P) fertilizers in agricultural soils is associated with several problems such as accumulation of phosphorous in the soil, heavy metal pollution, and eutrophication of surface water resources. The nano rock phosphate (nano RP) was found to be an efficient phosphorous fertilizer agronomically, but the transport behaviour of nano rockphosphate is still unknown. Therefore, an attempt was made in this study to investigate the transport behaviour of nano RP by conducting a short-term soil column experiment. The treatments were considered as control, Single Super Phosphate (SSP), bulk RP and nano RP at standard recommendations; each treatment was replicated three times. Leachate samples were collected after every water application. After 15^th day, the soil samples were extracted from the columns from three depths, 0-1cm, 9-10cm and 34-35cm. Leachate samples and soil samples were analyzed for Ortho-P and Total P. The mobility of Ortho-P is greater in nano RP treated soils compared to that of SSP and bulk RP treated columns. It may be due to its lowered particle size which has increased the solubility of P. The SSP treated columns have higher amounts of unevenly distributed total – P compared to that of nano and bulk RP treated columns, proving the reduction in P accumulation in nano RP treated soil. The nano sized phosphorous particles can increase the mobility of P and thereby reduce the accumulation of phosphorous in soils. Hence, the application nano RP may be the best alternative to SSP, to maintain a healthy soil environment. Long-term and field scale studies are suggestable to confirm the same transport behaviour of nano phosphorous in real field conditions.

 

Keywords: Nano-rockphosphate, phosphorus transport, soil pollution.