Abstract:The existing methods for measuring soil bulk density are found to have a number of deficiencies, for instance, they fail to meet the demands of rapid development of precision agriculture, modeling of ecological environment, and assessment of soil carbon storage for a large volume of accurate bulk density data. Therefore, researchers have worked out a technique that combines gamma-ray attenuation and visible-near infrared spectroscopy for determination of soil bulk density, and has been successfully applied to estimating soil carbon storage. In order to test this method for accuracy and applicability in measuring soil bulk density in hilly regions of South China, soil samples were collected from a hilly area of Nanning, Guangxi for analysis of soil bulk densities with this method. And then comparison was made of this method with the traditional one of using cutting rings to collect soil samples and oven-drying the samples for weighing in accuracy of the measurement. Results show that two methods were similar in accuracy, and both quite high in regression R2 , up to 0.92, and low in root mean square error between the two, accounting only for 4.48% of the means of the soil bulk densities obtained. It is, therefore, concluded that besides being time-saving, inexpensive and non-destructive, this method using γ-ray attenuation and visible-near infrared to determine soil bulk densities is quite high in accuracy and applicability in the hilly regions of South China.