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 CO 2, concentrations of ammonium (NH 4 +), nitrite (NO 2 −), and nitrate (NO 3 −), and NH 3 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 CO 2 in the unamended soil ranged from 25 to 159 mg CO 2-C kg −1 day −1 and NH 3 volatilization from 0 to 189 μg NH 3-N kg −1 day −1 . Application of biosolid increased production of CO 2 significantly 1.4-fold and volatilization of NH 3 11.5-fold. The EC explained most of the variation in production of CO 2, while particle size distribution explained most of the variation in volatilization of NH 3. The concentration of NH 4 + 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 NO 3 − were generally found in soil with EC < 64 dS m −1. The EC explained most of the variation in production of CO 2, and dynamics of NH 4 + and NO 3 − while clay positively and sand content negatively affected NH 3 volatilization. It was found that increases in EC inhibited C and N mineralization in soil of the former lake Texcoco.