Abstract
Salinity and acidity have affected several hundred million hectares of land throughout the globe which poses a major threat to global food security and biodiversity. Application of organic amendments for salt-affected soils has been identified as one of the most effective ways to mitigate salinity-induced problems and considered as a green technique offering twin benefits of waste load reduction and land reclamation. However, studies on reclaiming acidic-salt affected soils are limited. Therefore, this study aimed to determine the reclamation potential of biochars and organic amendments involving Gliricidia sepium biochar produced at 300 degrees C, 500 degrees C, and 700 degrees C, green waste compost, and municipal sewage sludge at three different amendment ratios, 1.0%, 2.5% and 5.0%. The incubation experiment was conducted for a 4-month period with different amendment ratios applied to the coastal acidic-salt affected soil. Subsamples were extracted from incubation pots after 1 and 4 months and analyzed for soil chemical parameters (pH, EC, NO3-, PO43-, total organic carbon, cation exchange capacity, sodium adsorption ratio, exchangeable sodium percentage) and microbial enzyme activity (catalase activity, and acid- and alkaline phosphatase activity). All organic amendments demonstrated enhancement of the soil properties in a significant manner. However, increasing incubation time and amendment ratio increase the changes of soil parameters by a great percentage. Therefore, the maximum amendment ratio of 5.0% and 4 months of incubation period rendered a significant improvement in the reclamation of acidic-salt affected soil. However, the biochar produced at 500 degrees C contributed the maximum towards the improved physicochemical and biochemical profile of acidic-salt affected soil, making it the most promising organic amendment for the reclamation of acidic-salt affected soil. The overall reclamation efficiency of organic amendments registered the following order of variation: 700 BC<Sludge<300 BC<Compost<500 BC.