ISSN:
1435-0661
Keywords:
RP, reactive phosphorus RP (〈0.45), reactive phosphorus 〈0.45 μm RP (〉0.45), reactive phosphorus 〉0.45 μm TP, total phosphorus TP (〈0.45), total phosphorus 〈0.45 μm TP (〉0.45), total phosphorus 〉0.45 μm UP, unreactive phosphorus UP (〈0.45), unreactive phosphorus 〈0.45 μm UP (〉0.45), unreactive phosphorus 〉0.45 μm
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
−1 NaHCO3 extractable P) and leachate was sampled over two drainage seasons. Export of total P was 〈0.5 kg ha−1 yr−1 for all soil types. Concentrations of total P in the leachate routinely exceeded 100 μg L−1 and remained relatively stable throughout the drainage season, except during the late spring period when maximum concentrations 〉200 μg L−1 were detected from all soil types. Physically, most of the leachate P was dissolved (〈0.45 μm), although 21 to 46% occurred in the particulate (〉0.45 μm) size fraction, most notably from the sandy-textured soils. Chemically, the leachate was dominated by reactive (inorganic) P from all soil types (62–71%), although a large proportion was in unreactive (organic) P forms (29–38%). Reactive P occurred mainly in the 〈0.45 μm fraction, while unreactive P was predominantly in the 〉0.45 fraction. Unreactive P in the 〈0.45 μm fraction was greatest during the springtime (April–May), probably reflecting microbiological turnover and release of P in the soil. Our results indicate that (i) subsurface P transfer from soil to surface water can occur at concentrations that could cause eutrophication and (ii) unreactive and 〉0.45 μm P forms are important in subsurface P transfer.
Type of Medium:
Electronic Resource
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