Water retention in soil refers to the ability of soil to hold water for use by plants. This process is influenced by soil texture, structure, and organic matter content. Soils with high clay content can retain more water, while sandy soils drain quickly and hold less moisture. Effective water retention is crucial for agriculture and gardening, as it ensures that plants have a steady supply of water. Techniques such as adding organic matter or using mulch can improve soil's water-holding capacity, promoting healthier plant growth and reducing the need for frequent irrigation.