Clay particles hold cations because they

Clay particles hold cations because they are negatively charged. Clay particles have a net negative charge due to the presence of various chemical components in their structure. This negative charge attracts positively charged cations, such as calcium, magnesium, and potassium, which are important nutrients for plant growth. The smaller size of clay particles also means that they have a larger surface area relative to their volume, which enhances their ability to attract and hold cations. The fact that clay particles can become hardened when dry or have definite shapes is not directly related to their ability to hold cations.