Detailed Explanation:

Contour bunding is a soil and water conservation technique used on sloping lands (typically 2-10% gradient) where earthen embankments are constructed along contour lines to reduce water runoff velocity and prevent soil erosion.

It is primarily employed in rainfed agricultural areas on gentle to moderate slopes, not in desert margins (where wind breaks are used), flat plains (where leveling/drainage is needed), or scrublands (where weed control is unrelated to contour structures).