12.2 Advantages and Disadvantages of Chemical Weed Control

Herbicides are widely used in United States field crop production systems.  Before deciding whether or not to incorporate these tools on a farm, it is important to carefully consider some of the advantages and disadvantages of using them.

Advantages

• Herbicides can control weeds where other methods are impossible due to plant arrangement or timing.
• Reduces number of tillage operations required, which can protect the soil and environment. This also results in decreased fuel costs and lower carbon emission.
• Reduces human effort required to manage weeds.
• May provide improved control of perennial weeds.
• Greater flexibility in choosing a management system. Before herbicides, farmers were required to have more crops in their rotation to control weed pressures.  With herbicides a 2 or 3 crop rotation is commonly used.

Disadvantages

• Herbicides can be expensive to apply.
• Applying herbicides can require a pesticide applicator’s license and some special equipment.
• There can be negative effects on non-target organisms, including toxicities to humans.
• They can cause injury to crops.
• Herbicide resistance in weed populations can develop, making the herbicide ineffective.
• Public concerns of environmental contamination and food safety.
• Farmers and agronomists can put too high of expectations on herbicide chemicals, thinking herbicides will solve all crop production weed challenges. In reality, solid agronomic principles are critical for effective weed management.

Researchers at the USDA (US Department of Agriculture), universities and private-sector companies are always looking into ways to maximize the advantages of herbicides, as well as reduce or eliminate the challenges from their disadvantages. Advances in technology are making site specific management more possible.  For example, variable rate applicators and smart sprayers reduce the amount of herbicide needed, which not only reduces costs to farmers, but also better protects the environment and reduces the appearance of herbicide resistance in weed populations.

The following video clip shows research that a group of universities have underway in developing an “Intelligent Sprayer”.