What plant is often used as a bioindicator of soil health?

Clover is often used as a bioindicator of soil health due to its ability to signal the presence of nutrients, particularly nitrogen. As a legume, clover has a symbiotic relationship with nitrogen-fixing bacteria in its root nodules, allowing it to convert atmospheric nitrogen into a form that can be used by plants. This characteristic not only enhances soil fertility but also improves soil structure and overall health.

The presence of clover in an area can indicate that the soil is rich in nitrogen and other essential nutrients, making it a good indicator of agricultural viability. Additionally, clover's ability to thrive in various conditions can provide insights into soil moisture levels and general soil quality.

In contrast, while grass is a common plant type and may reflect some aspects of soil quality, it does not have the same direct association with nitrogen levels as clover. Rosemary and tomato plants are not typically used as bioindicators of soil health since they are more sensitive to soil conditions and do not improve soil fertility in the same way that clover does.