[Dynamics characteristic of phosphorus loss potential in subsurface runoff from rice field]

A special rice field experiment was conducted to investigate the characteristic and mechanism of phosphorus (P) loss potential in subsurface runoff from rice field. Teflon Suction Cups (TSC) were inserted into tested plots in 15-20 cm in the rice field for water sampling dynamically. The range of molybdate reactive phosphorus (MRP) in sub-surface runoff were 0.110-0.273 mg/L, 0.085-0.285 mg/L during growth seasons of early rice and later rice, respectively. The magnitude of MRP concentrations in subsurface runoff in 15-20 cm from rice field was more consistent with trend of soil P accumulation (expressed as Olsen-P) due to P application. P concentration and its expected loss loading in the subsurface runoff in 15-20 cm in the rice field were not affected by P application combined with manure.