Sunflowers are harvested for oil, as a substitute for soybean meal for ruminant animals and as a silage crop. Their seeds are enjoyed as a snack by humans, with small seeds used as birdseed. Sunflower oil is used in paints, varnishes and plastics, soaps, detergents, surfactants, adhesives, fabric softeners and lubricants. The sunflower also shows potential as an alternate fuel source in diesel engines.
About 14 percent of the world's production of seed oils comes from sunflowers. Sunflower oil is commonly used in other countries, though it is not as popular in the United States. The oil is light in color and contains a high level of unsaturated fatty acids. It has a bland flavor and a high smoke point, making it valued for cooking and salad oil or in margarine. Though applicable in many manufacturing processes, the price of the sunflower makes its use cost prohibitive in many locations. The sunflower comprises 93 percent of the energy of U.S. Number 2 diesel fuel.
The straight stem of the sunflower culminates in a top made up of 1,000 to 2,000 individual flowers joined together. The leaves of the sunflower follow the sun's rays across the sky, increasing light interception. The plant has a strong taproot anchoring it to the ground, with lateral surface roots providing increased support. Pollination by insects and bees is important for increased yields.