Soil Phosphorus Forms and Profile Distributions in the Tidal River Network Region in the Yellow River Delta Estuary
Table 2
Mean soil phosphorus concentrations by fraction in tidal river network region soils listed as mg P kg−1 soil. Means were averaged from 18 soil samples in each type. Duncan multiple-range test was conducted with 17 degrees of freedom. The signification of different forms of phosphorus was described in [8].
P extract
BRB
RB
TB
TCB
Geochemical significance
Ecological significance
Resin-P
9.6c
11.0c
14.6b
16.6a
Nonoccluded, rapid turnover
Plant available
Bicarb-Pi
4.2c
4.9bc
5.8b
7.1a
Easily plant available,
Bicarb-Po
30.0b
40.8a
17.7c
37.6a
Easily mineralized
NaOH-Pi
4.0b
5.4a
5.7a
6.2a
Nonoccluded, slow turnover
Lesser plant available
NaOH-Po
32.0b
43.9a
25.7bc
22.1c
Not directly plant available
D.HCl-Pi
420.2a
417.4a
423.5a
414.6a
Occluded, slow turnover
C.HCl-Pi
45.0c
61.6b
73.8a
78.0a
C.HCl-Po
30.1a
22.0c
22.7bc
28.6ab
Residual-P
36.9c
42.0b
46.9a
47.1a
Pi
520.0c
542.4b
570.2a
569.5a
Po
92.1b
106.7a
66.1c
88.2b
Pt
612.1c
649.2ab
636.3b
657.8a
The a, b, c represent significant differences between means for groups, while means for groups in homogeneous subsets are displayed as ab and bc ().