Cm. Martinez et al., FACTORS INFLUENCING PHOSPHORUS ADSORPTION IN MINE SOILS IN GALICIA, SPAIN, Science of the total environment, 180(2), 1996, pp. 137-145
Available phosphorus levels and P sorption capacity were investigated
in soils derived from coal mine spoils at As Pontes (Galicia, NW Spain
), currently in the process of reclamation. Clays and shales, often in
conjunction with pyrite and other sulphides, are the main constituent
s of the spoils; many are extremely acid as a result of oxidation of s
ulphides. Reclamation tasks consisted of topsoiling, chemical and orga
nic fertilizing or various amendments. Two depths (0-15 and 15-30 cm)
were sampled and analysed at each sampling site. In total, 140 samples
were collected ranging in pH-H2O from 2.7 to 8.4. Olsen P values rang
ed between 1 and 54 mg . kg(-1). The phosphorus sorption index (PSI),
determined according to Bache and Williams (1971), ranged between 2.4
and 55.1. Multiple correlation between PSI and several soil parameters
was investigated using a stepwise linear regression method. Four soil
parameters (oxalate-extractable Fe and Al, pH in KCl and organic carb
on) were shown to explain 79% of the variance in log PSI. The correlat
ion equation found was: log PSI = 3.562 + 0.519 x log(Al + Fe)(o) - 0.
065 x pH-KCl + 0.247 x log(org. C).