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Growth, phosphorus uptake, and rhizosphere microbial‐community composition of a phosphorus‐efficient wheat cultivar in soils differing in pH
Author(s) -
Marschner Petra,
Solaiman Zakaria,
Rengel Zed
Publication year - 2005
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.200424101
Subject(s) - rhizosphere , soil water , chemistry , mineralization (soil science) , alkali soil , phosphorus , shoot , soil ph , agronomy , bulk soil , microorganism , soil organic matter , environmental chemistry , biology , bacteria , ecology , genetics , organic chemistry
In a pot experiment, the P‐efficient wheat ( Triticum aestivum L.) cultivar Goldmark was grown in ten soils from South Australia covering a wide range of pH (four acidic, two neutral, and four alkaline soils) with low to moderate P availability. Phosphorus (100 mg P kg –1 ) was supplied as FePO 4 to acidic soils, CaHPO 4 to alkaline, and 1:1 mixture of FePO 4 and CaHPO 4 to neutral soils. Phosphorus uptake was correlated with P availability measured by anion‐exchange resin and microbial biomass P in the rhizosphere. Growth and P uptake were best in the neutral soils, lower in the acidic, and poorest in the alkaline soils. The good growth in the neutral soils could be explained by a combination of extensive soil exploitation by the roots and high phosphatase activity in the rhizosphere, indicating microbial facilitation of organic‐P mineralization. The plant effect (soil exploitation by roots) appeared to dominate in the acidic soils. Alkaline phosphatase and diesterase activities in acidic soils were lower than in neutral soils, but strongly increased in the rhizosphere compared with the bulk soil, suggesting that microorganisms contribute to P uptake in these acidic soils. Shoot and root growth and P uptake per unit root length were lowest in the alkaline soils. Despite high alkaline phosphatase and diesterase activities in the alkaline soils, microbial biomass P was low, suggesting that the enzymes could not mineralize sufficient organic P to meet the demands of plants and microorganisms. Microbial‐community composition, assessed by fatty acid methylester (FAME) analysis, was strongly dependent on soil pH, whereas other soil properties (organic‐C or CaCO 3 content) were less important or not important at all (soil texture).