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Phosphorus Availability in an Artificially Flooded Southeastern Floodplain Forest Soil
Author(s) -
Wright R. B.,
Lockaby B. G.,
Walbridge M. R.
Publication year - 2001
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2001.6541293x
Subject(s) - mesocosm , floodplain , flooding (psychology) , phosphorus , phosphate , environmental science , soil water , zoology , hydrology (agriculture) , agronomy , nutrient , chemistry , ecology , soil science , geology , biology , psychology , geotechnical engineering , organic chemistry , psychotherapist
Studies of how flooding affects P availability in natural floodplains are rare. We examined the effects of artificial flooding on P availability in a Georgia floodplain forest. We hypothesized that P availability would increase with flooding, because of the flooding‐induced solubilization of phosphate minerals. Field mesocosms ( n = 4 per treatment) were flooded with river water according to one of four treatments over ∼6 mo: (i) continuously flooded; (ii) flooded for 3 mo and then drained; (iii) flooded for 2 mo, drained for 1 mo, and repeated; and (iv) nonflooded control. Two additional sets of 3‐mo flooded–drained mesocosms ( n = 4 per set) received added P or N (1 and 10 mg L −1 , respectively) with flooding. Soils were collected monthly from both inside and outside of the mesocosms and analyzed by Hedley fractionation; anion‐exchange resins (AER) were used to estimate P availability in situ. As indexed by daily supply to AER, P availability was significantly greater in flooded versus control soils, and decreased significantly following drainage, in all treatments at some time during the study. Total P supply to AER was significantly greater in flooded versus control mesocosms regardless of treatment. No significant changes were observed in Fe/Al phosphate fractions. Microbial P was significantly lower in flooded versus control mesocosms during the first 3 mo of flooding and decreased significantly over time in two treatments. In this natural floodplain, biological processes are a more probable explanation for flooding‐induced increases in P availability than solubilization of mineral phosphates.