The structure of loam could be described as crumbly. Loam is a type of soil that is made up of a mixture of sand, silt, and clay particles in roughly equal proportions. This balanced composition gives loam its unique texture, which is crumbly and friable. This means that it can be easily broken down into small pieces or crumbs when you squeeze it in your hand. This crumbly texture allows for good water retention and air circulation, making loam a suitable soil for growing a variety of plants.