In landscape horticulture, what role do organic amendments play in soil preparation?

Organic amendments play a crucial role in soil preparation primarily by improving soil structure and fertility. These materials, such as compost, manure, or leaf mold, enhance the physical properties of the soil. When incorporated into the soil, they help to aggregate soil particles, which improves aeration and drainage, thus creating a better environment for plant roots to develop.

Moreover, organic amendments are rich in nutrients and serve as a food source for beneficial soil microorganisms. As these microorganisms break down the organic matter, they release nutrients in a form that is readily available to plants, enhancing soil fertility. Additionally, the decomposition process contributes to the formation of humus, which improves nutrient retention and soil's ability to hold moisture.

While organic amendments can also indirectly affect factors such as soil acidity or water retention, their primary function in landscape horticulture is to bolster both soil structure and fertility to support healthy plant growth.