Which technique prevents light from reaching weed seeds, inhibiting their growth?

Mulching is an effective technique for preventing light from reaching weed seeds, which is crucial for inhibiting their growth. By applying a layer of organic or inorganic material on the soil surface, mulching blocks sunlight, effectively starving the seeds of the light they need for germination and growth. Additionally, mulch helps retain soil moisture and can improve soil quality as it decomposes, contributing to a healthier ecosystem that can outcompete weeds.

While mechanical control involves physical methods such as tilling or hoeing to manage weeds, it does not inherently block light; it primarily disrupts the existing plants. Controlled burning can help in managing certain types of vegetation and pests but mainly works through combustion, not by blocking light. Shading can inhibit growth but isn't a formal technique like mulching, which is specifically designed for this purpose, making mulching the most effective answer in this context.