SOIL ROUGHNESS MEASUREMENT - CHAIN METHOD

The methods commonly used to measure surface roughness involve measuring point elevation using a pin roughness meter or laser, both of which are labor intensive and expensive. A simple, fast, and inexpensive technique is needed to determine soil roughness in the field in order to obtain measurement for wide spread application. A method using a roller chain was developed to measure soil roughness. The chain method is based on the principle that as a chain of a given lenght, L1, is placed across a surface, the horizontal distance covered, L2, will decrease as the roughness increases. The chain lenght reduction caused by roughness was calculated as soil roughness, Roughness values obtained from the chain and those obtained by a multiple pin roughness meter were highly correlated (R2 = 0.96, P < 0.01). The results demonstrated the sensitivity of the chain method to soil surface roughness. A predictive equation was developed to predict roughness factor, K(r) [currently used in the Wind Erosion Equation (WEQ)] from the chain method. The chain method is inexpensive, fast, and easy to use and requires little training and no technical experience. It can provide a feasible technique to obtain roughness measurements.