D. Bermudez et al., ROLE OF EDDHA AND HUMIC ACIDS ON THE SOLUBILITY OF SOIL-PHOSPHORUS, Communications in soil science and plant analysis, 24(7-8), 1993, pp. 673-683
A greenhouse pot experiment was designed in order to test the effect t
hat the addition of two organic materials, EDDHA and humic acid would
have on the availability of P released from three P fertilizers, 8-24-
8, 20-20-20, and MAP (monoamonium phosphate). Phosphorus was extracted
from soil by three different methods (Burriel-Hernando, Olsen, and EU
F). Burriel-P and EUF-P were correlated according to the equation: Bur
riel-P = 3.9 x Fraction I + 2. 7 x Fraction II + 23.5: r = 0.7558 wher
e: Fraction I = EUF-P, 200 V, 30 min; and Fraction II = EUF-P, 200 V,
5 min. This relationship indicates that the Burriel-Hernando method ex
tracts both, soluble and insoluble forms of P. The effect of the organ
ic additions depend basically on the kind of fertilizer employed. EDDH
A increased P availability from 8-24-8, and humic acid did the same fo
r MAP. The differences between treatments for 20-20-20 were also depen
dent on the method of P extraction.