Fig. 4.

The simulated cumulative P uptake per plant of upland rice roots during a growing period of 52 d. Rice roots were grown under contrasting P rates [P deficiency (NoP), a sub-optimal P amendment in the topsoil (SubP) and a non-limiting P rate in the topsoil (PlusP)] and contrasting water regimes [field capacity (FC) vs. drying periods (DP)]. These simulations enable the differentiation among total P uptake, P uptake from the topsoil (0–20 cm depth) and P uptake from the sub-soil (>20 cm depth).