Around 9500 B.C.E., in a number of populations distant from one another, people began to select and cultivate plants for food and other purposes. These people were the first farmers. In what is now known as the Fertile Crescent in Southwest Asia, small populations engaged in small-scale farming and began to grow the eight founder crops of agriculture—emmer and einkorn wheat, hulled barley, bitter vetch, peas, chickpeas, lentils, and flax. However, it took thousands of years before the farmers developed the practices and technologies necessary to enable cultivation of the land on a larger scale.
In 5500 B.C.E. the first plow, a tool used to prepare the soil for planting, was developed in Mesopotamia by the Indus Valley Civilization. It was known as the scratch plow and represented one of the greatest advances in agriculture. It consisted simply of a wooden stick attached to a wooden frame, but was able to aerate the soil and scratch a furrow to allow the planting of seeds. The plow was pulled by domesticated oxen and left strips of undisturbed earth between each plowed row. To increase the productivity of their fields, farmers often cross-plowed them at right angles. The squarish fields that resulted are known to archeologists as "Celtic fields."
Many different types of plow have superseded this simple device, but it is still used in many parts of the world. In certain areas, including northern Europe, the scratch plow was ineffective in dealing with sticky clay soils. However, in India farmers continue to use the primitive plow to introduce organic materials into soils that have been cultivated for up to 2,000 years.
