The vegetative propagation technique in which the lower branch of a stem is bent and burried under the soil, while the growing shoot projects out of it is called:
Layering
Cutting, layering and grafting are artificial methods of vegetative propagation in which the plants are manually made to reproduce. Cutting involves development of a new plant from the cutting of its parent. While grafting is a technique by which the roots and shoots of the desired plants are joined to produce a new plant with the characteristics of both the parents.
Layering is an artificial vegetative propagation technique in which the lower stem of the parent plant is bent into the soil and the shoot is projected out of the soil to give rise to a new plant.
Budding is a natural asexual method of reproduction in which the plant body develops buds on its body surface that grows on the parent and then develops into an individual itself.