This type of landscaping is called terracing.
The Rice Terraces of the Philippine Cordilleras have been designated as a UNESCO World Heritage Site because of the significance of this technique.

A paddy field is a flooded field of arable land used for growing semiaquatic crops, most notably rice and taro. In agriculture, a terrace is a piece of sloped plane that has been cut into a series of successively receding flat surfaces or platforms, for the purposes of more +

effective farming. This type of landscaping is therefore called terracing. Graduated terrace steps are commonly used to farm on hilly or mountainous terrain. Terraced fields decrease both erosion and surface runoff, and may be used to support growing crops that require irrigation