Which of the following can decrease water drainage in fields?

Compaction of soil is a significant factor that can decrease water drainage in fields. When soil becomes compacted, the spaces between soil particles, known as soil porosity, are reduced. This compaction makes it difficult for water to permeate the soil, leading to increased surface runoff rather than infiltration. As a result, drainage is hindered, and water can pool on the surface rather than moving downward where it can be absorbed by plant roots or drain away effectively.

In contrast, the other options generally promote better drainage. For instance, planting cover crops can improve soil structure, enhance root development, and increase organic matter, which can all facilitate better water infiltration. Improving soil aeration also contributes to effective drainage by preventing compaction and maintaining space for air and water within the soil. Maintaining crop diversity can enhance soil health and reduce erosion, promoting better water retention and drainage dynamics. These practices work together to ensure that water can move efficiently through the soil profile, unlike compaction, which creates barriers to drainage.