Effects of reafforestation techniques on the nutrient content, photosynthetic rate and stomatal conductance of Pinus halepensis seedlings under semiarid conditions

A field experiment was carried out to evaluate the effect of different soil preparation techniques for Pinus halepensis afforestation on physiological parameters in Mediterranean summer conditions. The soil preparation treatments consisted of terracing (mechanical and manual) and the addition of an organic amendment (urban solid refuse). The mycorrhizal treatments consisted of nursery inoculation with Pisolithus arhizus and the addition of forest soil to the planting holes. Six years after planting the study revealed significant differences in heights and basal diameters, phosphorus and potassium concentrations in the leaves and photosynthetic rate and stomatal conductance. The pines grown in the manually prepared terraces were subjected to strong water stress, as reflected by the high A:g(s) ratios and highest levels of phosphorus and potassium in leaves. Mechanical terracing and the addition of urban solid refuse produced a higher photosynthetic rate, and a combination of these treatments was particularly effective. Copyright (C) 2000 John Wiley & Sons, Ltd.