Crop production A branch of agriculture that deals with growing or raising crops such as food , fiber, biofuel or medicinal products is called crop production. Food is things that people or animals eat. Fibers are thread that can be used for making products such as rope, paper and cloth. A fuel that is made from plant or animal sources is called biofuel . Soil The material on the top of the earth in which plants grow is called soil . Soil texture indicates the mineral components of soil. Sand, silt and clay are three main components of soil. The ability of a soil to grow crops is called soil fertility . The soil pH is a measurement of the level of acidity or alkali in soil.