Companion Planting

I am trying to find more information about the type of gardening or farming where you maybe plant a blueberry bush underneath an apple tree. This is supposed to allow natural type pesticides as well as keep soil rich.

Its called companion planting.

It can be used for various purposes. Some plants help to deter pests from other plants, such as garlic. Some help by attracting pests away from other plants, like planting aphid attracting Calendula next to roses. Some enrich the soil, like Dandelion that draws up nutrients from deep in the soil. Some contribute to the health of sickly plants, like chamomile (which also protects seedlings against damping off disease). Some attract beneficial insects that feed on insect that are infesting your garden, like Queen Anne's Lace that attracts parasitic wasps.

There are a number of excellent books out there that cover companion planting in depth, such as Carrots Love Tomatoes, Roses Love Garlic by Louise Riotte