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Isolation and characterization of labile organic phosphorus pools in soils from the Askov long‐term field experiments
Author(s) -
Guggenberger Georg,
Christensen Bent T.,
Rubæk Gitte H.
Publication year - 2000
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/(sici)1522-2624(200004)163:2<151::aid-jpln151>3.0.co;2-x
Subject(s) - chemistry , manure , phosphorus , environmental chemistry , soil water , agronomy , organic chemistry , soil science , environmental science , biology
Labile soil organic phosphorus (P o ) plays a crucial role in plant P nutrition and in environmental eutrophication. This paper discusses recent studies on the nature of labile soil P o and its response to different fertilization practices. Soil material was obtained from the Askov long‐term experiment on animal manure and mineral fertilizers. Our analytical approach combined a macroporous anion exchange resin to isolate labile P o and 31 P NMR spectroscopy to assess the chemical composition and origin of NaOH‐extractable P o . The analyses were carried out on fine earth (< 2 mm) and particle‐size fractions. The results suggest that the resin extraction isolates an active pool of soil P o that consists primarily of microbially‐derived compounds. The size of the active P o pool reflects seasonal variations and P fertilization. However, the source of added P (NPK vs. animal manure) appears to have only little influence on the labile P o . Our results further suggest that most of the active soil P o is associated with clay sized separates (< 2 μm), indicating this fraction being important in the short‐term turnover of P o .