Use of organic amendments to reclaim saline and sodic soils: a review

Soil salinity and sodicity are land degradation processes that strongly alter soil quality and consequently plant productivity. The reclamation of soils affected by salinity and/or sodicity is an important goal to maintain the sustainability of production. The objectives of this review were (1) to investigate the effectiveness of different organic amendments to reclaim saline/sodic soils and improve environmental quality and productivity of agro-ecosystems and (2) to provide useful information on the most appropriate waste management for minimizing any potential risks. To achieve these aims, recently published literature, related to field and laboratory studies, considering the effects of a wide range of organic amendments on main soil properties, was collected. Results of these studies underline that input of exogenous organic matter (manure, plant residues, by-product of farming or municipal activities, etc.) can be a feasible way to reclaim soils with serious problems of salinity and sodicity. Optimal rates (not greater than 50 t ha−1) of different organic amendments can improve physical (soil structure, permeability, water holding capacity, etc.) and chemical (pH, cation exchangeable capacity, etc.) soil properties, favoring plant growth and microbial activity, without any risks for the environment (subsoil and groundwater contamination). Of course, it is very important to characterize carefully the organic wastes before their use in agriculture and optimize their management, for avoiding further land degradation.