fate of fertiliser P in soil under pasture and uptake by subterraneum clover – a field study using 33P-labelled single superphosphate

• Published in: Plant and soil Vol. 401; no. 1-2; pp. 23 - 38
• Main Authors: McLaren, Timothy I, McLaughlin, Michael J, McBeath, Therese M, Simpson, Richard J, Smernik, Ronald J, Guppy, Christopher N, Richardson, Alan E
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.04.2016; Springer
• Subjects: Agricultural soils; Agrology; Biomedical and Life Sciences; Clover; Ecology; Fertilizers; field experimentation; granules; grazing; Life Sciences; nutrient uptake; Organic fertilizers; Organic soils; Pastures; Phosphates; phosphorus; Phosphorus cycle; phosphorus fertilizers; Plant Physiology; Plant Sciences; radiolabeling; Regular Article; shoots; soil; Soil fertility; Soil Science & Conservation; superphosphate; NSP; Improved grasslands; Trifolium subterraneum; Fertilizer; Phosphorus cycling
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-015-2610-6

BACKGROUND AND AIMS: Single superphosphate (SSP) is a major source of phosphorus (P) used in grazing systems to improve pasture production. The aim of this experiment was to determine the fate of fertiliser P in clover pastures under field conditions. METHODS: A procedure was developed to radiolabel SSP granules with a ³³P radiotracer, which was then applied to the soil surface (equivalent to ~12 kg P ha⁻¹) of a clover pasture. Recovery of fertiliser P was determined in clover shoots, fertiliser granules and soil fractions (surface layer: 0–4 cm and sub-surface layer: 4–8 cm). RESULTS: The P diffusion patterns of the ³³P-labelled SSP granules were not significantly different to those of commercial SSP granules (P > 0.05). Recovery of fertiliser P in clover shoots was 30–35 %. A considerable proportion of the fertiliser P (~28 %) was recovered in the surface soil layer and was largely inorganic P. CONCLUSIONS: Recovery of fertiliser P by clover plants was up to 35 % in the year of application. Much of the fertiliser P in soil fractions was inorganic P, which highlights the importance of inorganic P forms and dynamics in soils under clover pasture on a single season timeframe at these sites.