Regulation of soil phosphorus cycling in grasslands by shrubs

Publication date: Available online 23 February 2019Source: Soil Biology and BiochemistryAuthor(s): Xiao-Li Gao, Xiao Gang Li, Ling Zhao, Yakov KuzyakovAbstractThe globally expanding colonization of grasslands by shrubs increases soil organic carbon and nitrogen, but the effects of shrubs on phosphorus (P) cycling have been rarely studied. We compared P contents in roots and soil fractions, phosphatase activity in the 1 m profile, and in situ net P mineralization between shrubby Potentilla fruticosa patches and grassy interspaces in grazed shrubby meadows at three representative sites on the eastern Tibetan Plateau. The P uptake of P. fruticosa exceeded 1 m soil depth, whereas grasses acquired P mainly within the upper 0.6 m. The P contents in shoots, aboveground litter and roots under P. fruticosa were greater than those under grasses. Litter P stock under the shrubs was 4–8 times higher than that under grasses and the root P stock doubled compared to that in grass areas. P. fruticosa generally increased the organic P (OP) content in the topsoil but decreased inorganic P (IP) in the subsoil. Phosphorus availability increased in the topsoil but decreased in the subsoil under the shrubs compared to grasses. Microbial biomass P (MBP), the activities of acid and alkaline phosphatases, and OP lability were all greater in the 1 m soil under P. fruticosa than grasses, leading to faster P mineralization and the P turnover under the shrubs. In the 1 m soil, P. fruticosa in...
Source: Soil Biology and Biochemistry - Category: Biology Source Type: research