The Effect of Nano vs Micro Iron Oxide on Phosphorus Availability and Fractionation in Calcareous Soils

Phosphorus exhibits complex chemical behavior in response to such various soil factors as iron oxide. The effect of size and concentration of iron oxide particles on different forms of phosphorous in soil as well as its availability to plants was investigated. The study was conducted in the form of a factorial arranged experiment based upon a completely randomized design of four replications along with five levels of bulk iron oxide vs nano iron oxide (0, 500, 1000, 5000, 10000 mgkg-1).The results revealed that the use of iron oxide nanoparticles in all the samples reduced Olsen P concentration. The concentration was reduced from 3 mgkg-1 in bulk sample to 0.9 mgkg-1 in 5000 mgkg-1 nanoparticle sample, while this effect was not observed in the case of bulk iron oxide. A significant variation in Ca2-P, Ca8-P concentration was observed with changes in size and concentration of iron oxide, especially in Nano treatments. The changes in Ca10-P levels in the case of nano treatments were greater than those in bulk treatments, but not statistically significant. Iron oxide concentration significantly affected the level of Fe-P form. O-P form showed significant difference (compared with blank) only in the case of 10000 mgkg-1 of nano iron oxide.