Effect of Magnesium Chloride-Induced Salinity on Carbon Dioxide Evolution and Nitrogen Mineralization in a Silty Clay Loam Soil

A laboratory incubation experiment was conducted to evaluate the effect of magnesium chloride-induced salinity on carbon dioxide (CO2) evolution and nitrogen (N) mineralization in a silty loam nonsaline alkaline soil. Magnesium chloride (MgCl2) salinity was induced at 0, 4, 8, 12, 16, 20, 30, and 40.0 dS m(-1) and measured CO2 evolution and N mineralization during 30 days of incubation. Both CO2 evolution and N mineralization decreased significantly with increasing salinity. The cumulative CO2 evolution decreased from 235 mg kg(-1) soil at electrical conductivity (EC) 0.65 dS m(-1) to 11.9 mg kg(-1) soil at 40 dS m(-1) during 30 days of incubation. Similarly, N mineralization decreased from 185.4 mg kg(-1) at EC 0.65 dS m(-1) to 34.45 mg kg(-1) at EC 40.0 dS m(-1) during the same period. These results suggested that increasing magnesium chloride salinity from 4 dS m(-1) adversely affect microbial activity in terms of carbon dioxide evolution and N mineralization.