Weeds reduce crop yields by competing for:

• A. Moisture
• B. Light
• C. Soil nutrients
• D. All of the above

Answer: (D)

Weed competition for the essentials of plant growth is what drives yield loss. Weeds claim moisture from the soil, which reduces the water available for the crop—especially impactful in drier conditions or when irrigation is limited. They also form canopy and shade the crop, cutting down the light that reaches crop leaves and lowers photosynthesis and growth. In addition, weeds take up soil nutrients like nitrogen, phosphorus, and potassium, leaving less for the crop to use and slowing its development. Because weeds tap into all three resources, their presence typically lowers yields more than if they competed for just one resource. So the effect comes from competing for moisture, light, and soil nutrients—all of the above. Effective weed management reduces this competition and helps protect yields.