Gypsum-based management practices to prevent phosphorus transportation

Summary

Phosphogypsum from Siilinjärvi plant were tested in soil incubation-leaching-studies(I), and in liquid pig manure treatment (II) in farm pit.
In soil columns, gypsum additions significantly reduced erodibility and ortho-P concentrations in the leaching water.
In the pig manure test, the gypsum-based precipitate fractionated phosphorus to P-rich sediment and to almost P-free upper part. Upper low-P fraction represented 2/3 of the total manure volume.