Early Effects of Surface Liming on Soil P Biochemistry and Dynamics in Extensive Grassland

Liming effects on soil phosphorus (P) availability via biological P cycling are not clear. We conducted an 18-month field experiment on a long-term (60 years +) permanent fertilized grassland in a relatively dry environment. The aim was to examine the impact of liming on P biochemical processes and dynamics. Lime was applied at the beginning of the experiment to produce a soil pH range of 5.4–7.0, with no fertilizer P treatments. Soil sampling was conducted throughout the experimentation period at 0–75 mm. All soils were analysed for moisture content, pH, Olsen P, resin P, exchangeable aluminium (Al), microbial biomass P (MBP) and enzyme activities. At the final sampling, the soil samples were analysed for total C, total N and anaerobic mineralizable N (AMN). A sequential P fractionation was conducted for 0–30 mm depth samples. Liming effects on soil pH and P processes were limited to the surface 30 mm only, where labile inorganic P (Pi) fraction increased by 42