SUMMARY
Restoring the native vegetation is one of the most effective way to regenerate forest soil health. The seeding and plant establishment stages are critical; but during these stages the beneficial effects of the vegetation may not be apparent, and the soil is highly susceptible to erosion and depletion of soil quality. In the initial months after afforestation, vegetation cover establishment and soil quality could be better sustained if the soil was amended with an external extra source of organic matter. The objective of this study is to analyze the benefits of using different organic amendments on some soil properties. The soil treatment selected were: (i) afforestation with straw mulching treatment; (ii) afforestation with mulch with chipped branches of Aleppo Pine (Pinus halepensis Mill.); (iii) afforestation with cattle manure compost; (iv) sewage sludge and; (v) afforestation in unamended soils, control condition. The amendments were applied at the rate of 10 Mg ha-1. Six years after the amendment application, only the addition of straw and pine mulch have shown a significant increase in soil organic carbon regarding the afforestation under bare soil conditions. Besides, this increase was also directly related with the increase in microbiological activity and aggregate stability. On the other hand, the addition of sewage sludge or cattle manure is not an effective treatment to favor the edaphic structure regarding the afforestation under unamended soils.