Through locating experiment and verification analyses conducted in pilot research sites for mechanized terracing in Wuzhuangyuan plateau slopes of Xifeng District and Songpan gully sides in Zhengning County

Xifeng City

a simplified mathematic model of multiple varieties and non-lineal is concluded for planning bulldozer terracing

that satisfies four targets: the less consumption of labor force

less quantity of terrace edge

more convenient for mechanized farming

and stable terrace.An earth-labor value with relevant models is established for calculation

namely

work quantity and weighted average-quantity of earth transportation.The output has been extended throughout the 6 counties/city of the project area of Gansu Component of China Loess Plateau Watershed Rehabil-i tation Project I

and achieved good effects.