The years of intensive tillage in many countries, including Cambodia have caused significant decline in agriculture’s natural resources that could threaten the future of agricultural production and sustainability worldwide. Long-term tillage system and site-specific crop management can affect changes in soil properties and processes, so there is a critical need for a better and comprehensive process-level understanding of differential effects of tillage systems and crop management on the direction and magnitude of changes in soil carbon storage and other soil properties. This paper presents a study that was conducted in farmer’s field to evaluate the effect of conservation agriculture (CA) and conventional tillage (CT) on soil carbon, nitrogen and soil respiration in three villages of Siem Reap, Cambodia.