What is an effective method to reduce the weed seed bank in soil?

Regular tillage or cultivation is an effective method to reduce the weed seed bank in the soil because it disrupts the soil structure and brings buried weed seeds to the surface, where they are more likely to germinate. When seeds are brought to the top layers of the soil, they are exposed to environmental factors that can lead to their demise, such as desiccation, predation by animals, and unfavorable conditions for germination.

Additionally, regular tillage can help in controlling existing weed plants by severing roots and preventing them from re-establishing. It can also create a competitive disadvantage for weeds when followed by the establishment of desirable crops or plants that effectively utilize nutrients and resources, further minimizing the likelihood of weed establishment.

The other options do contribute to weed management but don't specifically target the reduction of the seed bank in the same direct manner. For example, periodic watering can encourage seed germination, and using cover crops can suppress weeds by providing competition and shading. Applying mulch effectively suppresses weed growth but does not directly reduce the existing seed bank in the soil.