Integrated Weed Management in Soybean

There is an array of understandings of what integrated weed management (IWM) should look like; thus, it has been defined in many different ways. Some defined it as “a combination of mutually supportive technologies in order to control weeds,” while others described it as “a multi-disciplinary approach to weed control utilizing the application of numerous alternative control measures.” Regardless of the definition, in practical terms, it means developing a weed management program using a combination of preventive, cultural, mechanical, and chemical practices. It does not mean abandoning chemical weed control, but relying on it less. Much has been written about IWM in various journals and books; thus, the objective of this chapter is not necessarily to provide an existing overview of the literature of various aspects of IWM, but rather to synthetize various aspects of IWM into a package that can be utilized by those who work and live in the applied world of weed science (e.g., practitioners). A single weed control measure is not feasible due to the number of different weed species and their highly diverse life cycles and survival strategies. In addition, controlling weeds with one or two methods provides the weeds a chance to adapt to those practices. Therefore, instead of using a particular weed control method, IWM suggests the use of a mixture of control methods that minimize the economic impact of weeds. Applying the principles of IWM can reduce the use of herbicides applied to the environment and at the same time provide optimum economic returns to the producers. In essence, the development of an IWM program is based on a few general principles that can be used at any farm: (1) use agronomic practices that limit the introduction and spread of weeds (preventing weed problems before they start), (2) help the crop compete with weeds (help “choke out” weeds), and (3) use practices that keep weeds “off balance” (do not allow weeds to adapt). Combining agronomic practices based on the above principles will allow designing an IWM program for any farming operation. IWM program is not a “recipe”; it needs to be changed and adjusted to the particular farming operation not just in soybean but in any crop. The goal is to manage, not eradicate, weeds.