Raising crops involves a few simple principles. Although farming has been around for about 10,000 years a vast sweep of time in which tools and methods have changed a great deal the basic principles remain the same. The first step in farming involves preparing the land for planting. The second step involves planting the seeds (or cuttings or seedlings). The third step involves helping the seeds to grow. The fourth step involves harvesting the mature plants and often processing them so that they can be used as food. (Fruit-growing and raising livestock for milk and meat are other types of farming.) Preparing land for planting involves breaking up the soil with a plow. Early plows were heavy pointed sticks that people pushed through the earth. Later, the points of plows were made of iron, and their shape became broader and flatter. (Plow blades are called shares.) These plows sliced bigger furrows (big grooves) into the soil and flipped
it over as well. While first powered by people, plows were soon designed to be pulled by animals because they had to be heavy to cut through hard ground. Usually a team of oxen or horses pulled a plow while a farmer guided and pushed it from behind. Today,
powerful tractors pull plows that dig up several furrows at a time. After plowing, early farmers pulled heavy rollers and harrows flat rake-like devices over the broken soil to make it even finer and ready for planting. Today, cultivators with rows of pointed metal prongs are pulled behind tractors to do the same job. Before planting machines, farmers sowed seeds by hand. It was a wasteful process because the wind blew seeds away as they were scattered and hungry birds ate them before they could be covered up by dirt. But in the early eighteenth century an English farmer named Jethro Tull greatly improved the sowing process by inventing the seed drill. It was a machine that cut several grooves into the soil and then dropped small amounts of seeds held in a compartment called a hopper down tubes or chutes into the neat rows. Crops could be grown in straight lines then, which made weeding easier; special hoeing machines were made with blades that fit between rows of crops to uproot weeds. Like a plow, the seed drill was usually pulled by horses and guided by a farmer who walked behind it. Today, of course, tractors provide the power that pulls similar sowing machines. There was not a lot that early farmers could do to help seeds grow once they were in the ground. At that point, it was really up to nature to provide the things that were needed for growth like warmth, sunlight, and water in the right amounts. Early farmers could add natural fertilizers (like manure) to enrich soil, and they could pull weeds that competed with growing plants. They knew about the benefits of rotating crops (growing different plants in different fields each year to keep the soil fertile and free of diseases and pests). In dry areas, early farmers even developed irrigation systems that delivered water to crops. But modern science has given today’s farmers many more reliable tools to help seeds grow. Chemical insecticides, for example, kill pests that threaten crops and selective herbicides kill weeds without damaging growing plants; other chemicals called fungicides help eliminate plant diseases. In addition, genetically altered plants and chemical fertilizers have allowed modern farmers to grow more plants than ever before. Before modern machinery, harvesting crops was a painstaking process. Gathering and removing mature plants from the field had to be done by hand. Farm workers used sharp bladed, long-handled scythes and curved sickles to cut down cereal crops like wheat. Even the fastest reaper could only clear about a third of an acre a day. Because rain could ruin harvested wheat, workers called sheaf-makers quickly tied it into bundles, so that it could be safely stored if the weather turned stormy. During the long winter months farm workers used jointed wooden tools called flails to thresh or beat the dried wheat in order to separate its edible grain seeds from its stalks. But in 1786 a machine that threshed wheat by rubbing it between rollers was invented, replacing human threshers. And around 1840 a reaping machine whose revolving wheel pressed grain stalks against a sharp blade that cut them down replaced human harvesters. Today, farm machines called combine harvesters do this work in much the same way. These machines are very efficient and combine all three jobs of cutting, collecting, and threshing a crop. A single combine harvester can process five acres of wheat in less than an hour!