Salinity and Plant Residue Effects on Soil Available Phosphorus

The effect of salinity and plant residue on soil phosphorus (P) availability was investigated. The organic carbon content of non-saline and salinized soil samples was enhanced by 1% with applying separately different amounts of residues. Fourteen residues including roots and shoots of wheat, barley, corn, alfalfa, and clover as well as leaves of apple, oak, plant-tree, and oleaster were used. Less available P was found in the non-saline soil compared to the saline soil. Plant residues appeared to have different impacts on availability of P. The salinity influence on soil P varied in different residues. The greatest increase (307%) in available P by salinity was found in the soil treated with alfalfa leaves. By increase in the total P in the plant materials up to 0.6% the positive effect of salinity on the available P decreased and then increased at higher concentrations of total P in the plant residues.