Like many field crops, soybeans are grown from seed planted in rows in the field. The soybean seeds are mature soybeans that are cleaned and bagged specifically for use as seed. Farmers select seed based on desireable plant characteristics, like high yield, ability to withstand drought, color, or ability to withstand wind and weather. In North Carolina, farmers plant soybeans beginning in May and as late as July.
Seed may be planted in cultivated or tilled land by a tractor and a planter which deposits the soybean seed about 1 1⁄2 inches deep in rows that are up to 30 inches apart. There is no rule about how wide rows must be, but 30 inches is typical.
Or soybeans may be "drilled" into the ground in seven-inch rows by a special "no-till" planter. When a farmer uses the "no-till" method, the land is not cultivated and the seeds are planted directly into the stubble left over from the previous crop, for example wheat harvested in May or June. The "no-till" method is a great improvement that saves time, conserves moisture and greatly decreases the possibility of soil erosion. "No-till" is often acceptable for farmers, but sometimes tillage is required, especially for dealing with fields infested with pests like tough weeds.
Large tractors and multi-row planters are used to plant many rows at the same time. This requires fewer trips across the field and more works gets done in less time.
When the soybeans sprout and small plants begin to grow (about four to seven days after planting), there are many things a farmer must consider to protect his crop. The farmer has already invested in seed, planting, and weed control and wants the crop to grow its best. Bugs and worms really like small tender plants; so when the farmer notices that there is a heavy insect infestation, he or she must calculate the degree of risk to the crop. If the infestation is bad enough to harm the crop, the farmer sprays a pesticide to control the harmful pests. If the farmer is using organic methods, there are still products that can be sprayed but the choice is much more limited, and the risk is somewhat greater.
Another threat to the young crop comes from weeds that grow faster than soybean plants. They can crowd out the soybean plants and prevent necessary sunlight and nutrients from enabling the soybean plants to grow strong and healthy. This will reduce the soybean yield. Also, if allowed to grow some weeds will produce seeds that will be harvested with the soybeans and will reduce the value. The farmer will get less money when he sells his soybeans if there are lots of weed seeds in with the soybeans.
In July, August and September, the plants bloom. The flowers are small and vary from a white to a beautiful violet or purple. From these blossoms, the soybean plant grows small pods that contain the young seeds. The soybean is a self-pollinating plant, which means that each flower has male and female parts. A single plant can produce seed and essentially clone itself. Soybean plants produce many more flowers than they need, so many flowers never produce pods.
If you are driving through rural parts of North Carolina, particularly in the east, you may see acres and acres of soybeans growing. From your vehicle, fields of soybeans, peanuts and cotton may look alike. You can usually tell the difference between soybeans and cotton by the large white, pink or red flowers that are visible on cotton plants, or by white bolls later in the season. Peanuts grow much closer to the ground in mounds. Soybeans are a deep green with a slightly paler shade of silver-green on the underside of the leaf.
About 75% of soybeans are grown in the eastern part of North Carolina, and if you are driving in this part of the state in the summer and early fall, you are sure to see some soybeans.
In late September, the soybeans begin to mature. As the days get shorter and the temperatures get cooler, the leaves on soybean plants begin to turn yellow. By mid-October and November, the leaves will turn brown and fall off, exposing the matured pods of soybeans.
The soybeans are now ready to be harvested. Combines are large machines for harvesting soybeans and other grains including corn and wheat. The header on the front of the combine cuts and collects the soybean plants. The combine separates the soybeans from their pods and stems and collects the soybeans into a holding tank in the back of the combine.
When the tank is full, the combine operator will empty the soybeans from the holding tank into a grain truck or grain wagon.
Soybeans are either taken directly to a grain dealer in the grain trucks or they are taken to storage facilities and stored until the farmer decides to sell them. Ultimately the soybeans are transported to a processing plant where the soybean meal (the protein component of the bean) is separated from the soy oil components. The meal is used for livestock feeding and the oil is used for cooking oil, for industrial purposes like manufacturing ink, paint, and solvents, and for soy biodiesel production for fuel use.