This document outlines a research study on sandy acid soils in Cambodia. The study aims to 1) identify the origins and formation processes of sandy soils in different parts of Cambodia, 2) explore similarities and differences in physical and chemical properties of sandy acid soils across Cambodia, and 3) identify the effects of soil properties on crop growth and yields. The methodology will involve soil profiling, analysis of physical and chemical properties, and pot and field experiments on different soil types with crop treatments. The conclusions will determine key differences in soil origins, properties, and constraints to crop production on different sandy soil types in Cambodia.