Increased supplies without increased use could result in such a low price. Again, increased supplies without increased use could result in such a low price. In addition, the market would have to expect another good crop in South America and more acres in the United States next year. The management involves deciding when, where, and how to control weeds. The crop needs nutrients, water, and light.
Weeds compete with the crop for nutrients, water, and light.
Yield loss from weeds depends on which weed species are present, when the weeds are present, weed density, and growing conditions. Weed species differ in how well they compete with crops. The germination and emergence of an individual weed species depends on soil temperature, soil moisture, and light requirements. Economics dictate that weeds should be controlled when the cost of weed control is less than the cost in lost yield from weed competition. Unfortunately, biology dictates that weeds left uncontrolled produce seed for future weed problems.