A soil phosphorus dynamics (SPD) model

The dynamics of
soil phosphorus (P) control its bioavailability. Yet, it remains
a challenge to quantify soil P dynamics. Here, we developed a soil P dynamics
(SPD) model. We then assimilated eight datasets of
426-day changes in Hedley P fractions into the SPD model, to quantify the dynamics
of six major P pools in eight soil samples that are representative of a wide
type of soils. The performance of our SPD model was better for labile P, secondary mineral P, and occluded P
than for non-occluded organic P (Po) and primary mineral P. All parameters
describing soil P dynamics were approximately constrained by the datasets. The
average turnover rates were labile P 0.040 g g-1 d-1,
non-occluded Po 0.051 g g-1 d-1, secondary mineral P
0.023 g g-1 d-1, primary mineral P 0.00088 g g-1
d-1, occluded Po 0.0066 g g-1 d-1, and
occluded inorganic P 0.0065 g g-1 d-1, in the greenhouse
environment studied. Labile P was transferred on average more to non-occluded
Po (transfer coefficient of 0.42) and secondary mineral P (0.38) than to plants
(0.20). Soil pH and organic C concentration were the key soil properties regulating
the competition for P between plants and soil secondary minerals. The turnover rate of labile P was positively correlated with
that of non-occluded Po and secondary mineral P. The pool size of labile P was
most sensitive to its turnover rate. Overall, we suggest data assimilation
can contribute significantly to an improved understanding of soil P dynamics.

Paper on this data and model is published as follows: Hou, E., Lu, X., Jiang, L., Wen, D. & Luo, Y. Quantifying soil phosphorus dynamics: a data assimilation approach. Journal of Geophysical Research: Biogeosciences 124, 2159-2173 (2019).