Carbon and nitrogen mineralization in different upland soils of the subtropics treated with organic materials

Use and management of organic waste/residues is currently an important global issue for attaining sustainability in agricultural production. However, knowledge about the decomposition characteristics and nutrient release pattern of added organic materials in subtropical soils and their interaction with inherent soil properties are lacking. Thus, laboratory incubation studies were carried out under aerobic conditions with crop residues and chicken manure (1%) applied to six contrasting soils. In all cases, CO2-C effluxes peaked by day 9 and the active C release phase persisted until day 25, indicating that priming effects might have occurred. The high pH and non-calcareous soils had higher CO2 effluxes than the acidic soils. The relative loss of added C differed between soils and its magnitude depended on…