Effects of plant species on microbial biomass phosphorus and phosphatase activity in a range of grassland soils

• Published in: Biology and fertility of soils 2004-10, Vol.40 (5), p.313-322
• Main Authors: Chen, C.R, Condron, L.M, Davis, M.R, Sherlock, R.R
• Format: Article
• Language: English
• Subjects: acid phosphatase; Agronomy. Soil science and plant productions; alkaline phosphatase; Biochemistry and biology; Biological and medical sciences; Biomass; Chemical, physicochemical, biochemical and biological properties; enzyme activity; Fundamental and applied biological sciences. Psychology; genetic soil types; grassland soils; Grasslands; Lolium perenne; Microbial activity; Microbiology; Mineralization; phosphoric diester hydrolases; phosphorus; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Pinus radiata; Plant species; root exudates; soil microorganisms; soil nutrient dynamics; soil respiration; Soil science; Soil types; Soils; Wood products
• ISSN: 0178-2762; 1432-0789
• DOI: 10.1007/s00374-004-0781-z

Soil P transformations are primarily mediated by plant root and soil microbial activity. A short-term (40 weeks) glasshouse experiment with 15 grassland soils collected from around New Zealand was conducted to examine the impacts of ryegrass (Lolium perenne) and radiata pine (Pinus radiata) on soil microbial properties and microbiological processes involved in P dynamics. Results showed that the effect of plant species on soil microbial parameters varied greatly with soil type. Concentrations of microbial biomass C and soil respiration were significantly greater in six out of 15 soils under radiata pine compared with ryegrass, while there were no significant effects of plant species on these parameters in the remaining soils. However, microbial biomass P (MBP) was significantly lower in six soils under radiata pine, while there were no significant effects of plant species on MBP in the remaining soils. The latter indicated that P was released from the microbial biomass in response to greater P demand by radiata pine. Levels of water soluble organic C were significantly greater in most soils under radiata pine, compared with ryegrass, which suggested that greater root exudation might have occurred under radiata pine. Activities of acid and alkaline phosphatase and phosphodiesterase were generally lower in most soils under radiata pine, compared with ryegrass. The findings of this study indicate that root exudation plays an important role in increased soil microbial activities, solubility of organic P and mineralization of organic P in soils under radiata pine.