Preliminary study on the association of lanthanum and phosphorous loss from soil

Through laboratory lysimeter experiments and artificial rainfall experiments, characteristics of P and La transportation from both vertical and horizontal directions are investigated. The association between La and P loss from soil is preliminarily discussed. Results of lysimeter experiment show that both La and P are difficult to transport vertically. Downward depths are no deeper than 6-8 cm for all forms of La and P. With the increasement of exogenous La amount, the amount of Water soluble P, NaHCO₃-extractable P and NaOH-extractable P decrease, while HCl-extractable P and residual form of P increase. Results of artificial rainfall experiment show that majority of La and P transport with fine soil particles in runoff, which is more than 95%. Loss of total P and La in runoff from the manure-applied soil are correlated significantly, both in loss rate and loss amount.