Fluoride accumulation in pasture forages and soils following long-term applications of phosphorus fertilisers.
Ingestion of soils with high fluoride (F) concentration may cause chronic fluorosis in grazing animals. Analysis of New Zealand pasture soils with long-term phosphorus (P) fertilisation histories showed that total surface soil (0-75 mm depth) F concentration increased up to 217-454 mg kg-1 with P fertiliser application. One-third to two-thirds of F applied in fertilisers resides in the top 75 mm soil depth. Pasture forage accumulation of F was low, and therefore, F intake by grazing animals through pasture consumption is expected to be much lower than F intake by soil ingestion. Ten annual applications of single superphosphate (30 and 60 kg P ha-1 year-1) to a Pallic Soil (Aeric Fragiaqualf) significantly increased total F and labile F (0.01 M CaCl2 extract) concentrations to 200 and 120 mm depths, respectively, of the 300 mm depth investigated. The mobility of F in the soil profile was similar to two other elements, P and cadmium derived from the fertiliser.
Loganathan
P
P
Fertilizer and Lime Research Center, Institute of Natural Resources, Massey University, Palmerston North, New Zealand. p.loganathan@massey.ac.nz
Hedley
M J
MJ
Wallace
G C
GC
Roberts
A H
AH
D000383:Agriculture; D000818:Animals; D002104:Cadmium / Q000032:analysis*; D005308:Fertilizers; D005459:Fluorides / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D008954:Models, Biological; D009520:New Zealand; D010758:Phosphorus / Q000008:administration & dosage / Q000032:analysis*; D010944:Plants / Q000737:chemistry*; D012987:Soil / Q000032:analysis*
D005308:Fertilizers; D012987:Soil; D002104:Cadmium; D010758:Phosphorus; D005459:Fluorides