Next, the slurry was alkalized with a 10% solution of lime milk (calcium hydroxide solution contained 10% of CaO, produced from technical grade, 95% CaO; Lhoist SA., Poland), to obtain a pH from 9.0 to 10.5; then, we added superphosphate (Luvena SA., Lubon, Poland) in amounts that comprised 3% e8% of the initial manure weight (Table 2) and the mixture was again alkalized with lime milk to obtain a pH from 9.0 to 10.5 (Table 3).