The science and art of cultivating the soil, including the allied pursuits of gathering in the crops and rearing livestock; tillage, husbandry, farming (in the widest sense): The science of agriculture includes the art and business of cultivating soil, producing crops, and raising livestock.

In her classes, Mary learned about agriculture as being the process, business, or science of producing food, feed, fiber, and other desired products by the cultivation of certain plants and the raising of domesticated animals (livestock).

Desert agriculture or agriculture in very dry areas: Arid-agriculture includes research in how to increase the agricultural productivity of lands dominated by a lack of freshwater, an excessive abundance of heat and sunlight, and usually one or more of extreme winter cold periods, short rainy season, saline soil or water, strong dry winds, and poor soil structure.

The use of geothermic heat in farming: Geothermal agriculture is the use of low-temperature geothermal water to warm irrigation water or to sterilize soil.

A modern method of producing food which is characterized by the use of high-yield varieties of crops and livestock, in connection with intensive inputs in the form of machinery, energy, fertilizers, hormones, antibiotics, and other chemicals, and irrigation water: "Industrial agriculture is much more energy-intensive than traditional agriculture, and there are those who also say it results in larger crop yields."