What tool is designed for boring into soil to get samples?

The tool designed specifically for boring into soil to obtain samples is the soil auger. This tool features a cylindrical shaft with a spiral or corkscrew-like blade that allows it to penetrate the ground efficiently. As it rotates into the soil, it collects a core sample, which is valuable for assessing soil composition, moisture content, and other characteristics necessary for agricultural or environmental analysis.

In contrast, a garden trowel is primarily intended for digging, transplanting, and moving small amounts of soil or plants, making it unsuitable for extracting soil samples. A boring bar is typically used in different contexts such as machining operations and isn't designed for soil sampling. Lastly, a post hole digger is used for digging deeper holes to install posts and fences; while it removes soil, it does not provide the core sample needed for analysis. Therefore, the soil auger stands out as the correct choice for its specific function in soil sampling.