Which material is commonly added to improve drainage in heavy soils?

Adding sand to heavy soils is a common practice to improve drainage. Heavy soils, such as clay, tend to retain water due to their small particle size and compactness, which can lead to poor drainage and aeration. By incorporating sand, the larger particles create spaces between the soil particles that facilitate the movement of water through the soil profile. This enhanced drainage not only helps prevent waterlogging but also improves the overall structure of the soil, making it more conducive to plant growth.

In contrast, clay, being fine-grained, exacerbates drainage issues when added to heavy soils. Silt may not significantly influence drainage either since it can retain moisture and compact similarly to clay. Peat, while beneficial for water retention and improving organic matter, does not enhance drainage effectively in heavy soils. Thus, sand stands out as the ideal choice for improving drainage in such conditions.