What characteristic of sand allows for good aeration and water passage?

The characteristic of sand that allows for good aeration and water passage is its larger pore space. Sand particles are relatively large compared to those of clay or silt, resulting in gaps or voids between the particles. These larger pore spaces enable air and water to move freely through the soil, which enhances drainage and aeration. Proper aeration is crucial for rooting systems, as it provides the necessary oxygen for plant roots to thrive while preventing issues related to waterlogging.

In contrast, smaller particle sizes found in clay result in tighter packing and small pore spaces, which can restrict both air and water movement. The surface area of sand is not as critical as its pore space when considering aeration and drainage; while larger surface areas can increase the soil's ability to hold nutrients, they can also reduce pore space if the particles are too fine. Compact nature refers to how tightly soil particles are packed together, which usually leads to reduced aeration and increases water retention, counteracting the benefits of good aeration and drainage.