Emission of carbon dioxide and dynamics of inorganic N in a gradient of alkaline saline soils of the former lake Texcoco

A plan was developed to apply biosolid to soil of the former lake Texcoco to fertilize the pioneer vegetation. Because, no information exists about how differences in electrolytic conductivity (EC) might affect mineralization of biosolid and dynamics of C and N in soil, 20 soil samples forming a gradient in EC ranging from 22 to 150 dS m−1 were characterized, amended with 500 mg biosolid C kg−1 dry soil and incubated aerobically at 22 ± 2 °C while production of CO2, concentrations of ammonium (NH4+), nitrite (NO2−), and nitrate (NO3−), and NH3 volatilization were monitored at 22 ± 2 °C for 70 days. Soil characteristics showed large variations with maximum values often >10-times larger than minimum values. The production of CO2 in the unamended soil ranged from 25 to 159 mg CO2-C kg−1 day−1 and NH3 volatilization from 0 to 189 μg NH3-N kg−1 day−1. Application of biosolid increased production of CO2 significantly 1.4-fold and volatilization of NH3 11.5-fold. The EC explained most of the variation in production of CO2, while particle size distribution explained most of the variation in volatilization of NH3. The concentration of NH4+ in the biosolid-amended soil decreased sharply in the first 14 days, with the EC explaining most of the variation found, and remained constant thereafter with a small increase at day 70. Significant increases in the concentration of NO3− were generally found in soil with EC < 64 dS m−1. The EC explained most of the variation in production of CO2, and dynamics of NH4+ and NO3− while clay positively and sand content negatively affected NH3 volatilization. It was found that increases in EC inhibited C and N mineralization in soil of the former lake Texcoco.