Effects of Rate of Application and Time on Phosphorus Sorption by Soils

Abstract Several soils from southern California were treated with different rates of phosphorus (P) and then incubated in 0.01 M CaCl 2 to measure the effect of incubation time up to 84 d at 25°C. There were only small effects of incubation times beyond 3 d for low rates of P applications. At higher rates of application those soils that were deficient in P as indicated by the NaHCO 3 test (< 10 µg P extracted/g) gave increased P sorption with increase in incubation time beyond 3 d. Those soils well supplied with available P reached equilibrium in 3 d. In those soils deficient in P, equilibrium was attained by the 42nd d of incubation.