The role of organic amendmens in drylands restoration

Dryland areas are being seriously affected by degradation processes. The use of organic amendments in ecosystem restoration is an effective technique for accelerating soil regeneration processes in degraded drylands. This recovery is a result of the rapid increment of organic matter and clay contents in the soil in the short term. In the long-term, soil structure becomes more stable and water holding capacity, permeability and infiltration are improved, whereas surface runoff and erosion are reduced. This review evaluates the role of organic amendments as an effective strategy in dryland restoration, highlighting the effects of different amendment types, doses and application rates. The major points of our analysis are: (a) the effects of the amendment on soil properties largely depends on the amendment origin; (b) amendments need to be applied at the minimum effective doses; (c) the form of application most extensively applied is on the soil surface (on-top); and (d) the stability and maturity of amendments can make the difference between success and failure.