Some soils, such as sandy soils, have a loose crumb structure with good drainage, whereas in clay soils the particles are small and stick together to give a dense crumb structure and poor drainage.

• 一些土壤例如砂土具有松散的结构，因而有良好的排水性，而在粘土中，由于土壤颗粒小而互相粘合导致粘土结构紧密排水性较差。