Increased availability of phosphorus after drying and rewetting of a grassland soil: processes and plant use

• Published in: Plant and soil Vol. 370; no. 1/2; pp. 511 - 526
• Main Authors: Bünemann, E. K., Keller, B., Hoop, D., Jud, K., Boivin, P., Frossard, E.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01.09.2013; Springer Netherlands; Springer Nature B.V
• Subjects: Agricultural soils; Agronomy. Soil science and plant productions; Animal, plant and microbial ecology; Bioassay; Biogeochemistry; Biological and medical sciences; Biomedical and Life Sciences; Clay soils; Drying; Ecology; Environmental aspects; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Grassland soils; Grasslands; Life Sciences; Organic soils; Phosphorus; Phosphorus content; Physical properties; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Plant Physiology; Plant Sciences; Regular Article; Soil biochemistry; Soil chemistry; Soil microorganisms; Soil science; Soil Science & Conservation; Soil sterilization; Soil water; Soil-plant relationships. Soil fertility; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Soils; Structure, texture, density, mechanical behavior. Heat and gas exchanges; Water and solute dynamics; Zea mays; Switzerland; Soil moisture fluctuation; Aggregate stability; Resin-extractable P; Soil sterilization; Microbial P; Split-root experiment; Structure stability; Process; Sterilization; Experimentation; Resins; Grassland soil; Availability; Fluctuations; Split-root technique; Extractability; Soil moisture; Property of soil; Phosphorus; Physical properties; Soil water properties; Wetting drying cycle; Microorganism; Aggregate; Soil plant relation
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-013-1651-y

Aims Drying and rewetting (DRW) often increases soil phosphorus (P) availability. Our aims were to elucidate underlying processes and assess potential plant uptake of released P. Methods Using a grassland soil with low available and high microbial P as a model, we studied the contributions of microbial and physicochemical processes to P release by determining DRW effects on i) C:P ratios of nutrient pulses in fresh and sterilized soils, ii) aggregate stability and iii) P forms released upon soil dispersion. Use of the P pulse by maize was examined in a bioassay and a split-root experiment. Results The strong P pulse after DRW was larger than that observed for C. Experiments with sterilized soil pointed to a non-microbial contribution to the pulse for P, but not for C. Aggregate disruption after DRW occurred due to slaking, and this released molybdate-reactive and -unreactive P. Maize benefitted from the P pulse only in the bioassay, i.e. when planted after the DRW cycle. Conclusions The majority of C and P released upon DRW originated from the microbial biomass, but for P release, physicochemical processes were also important. In the field, the released P would only be available to drought-resistant plants.