Date of planting can influence the type and number of weeds present. In general, optimum soil temperature at planting time will help the crop emerge quickly and out-compete weeds that emerge with or shortly after the crop. Planting corn as soon as possible after the risk of frost has passed may allow the crop to better compete against later-emerging weeds. Early plantings run the risk of cool-wet soils, frost, and a greater possibility of plant disease and herbicide injury, while delayed plantings generally do not yield as well as earlier seedings. The weed species present in a field along with its potential severity may help determine the best time for planting.
Few producers appreciate the benefits of crop rotation.
For example, rotation to perennial forage crops, such as alfalfa or grass, allow mowing as a weed-management tool. Even a simple rotation from corn to soybeans can allow both additional tillage and herbicide opportunities. Mechanical weed control includes the use of preplant tillage such as plowing, disking, and field cultivating. These primary and secondary tillages can help reduce the rate and spread of certain perennial weeds. Postplanting operations such as rotary hoeing, row cultivating, and hand hoeing can help reduce dependence on herbicides.