In geography and agriculture, arable land (from Latin arāre; “To plough, To farm”) is land that can be used for growing crops. It includes all land under annual crops (double-cropped areas are counted only once), temporary meadows for mowing or market and kitchen gardens and land temporarily fallow (less than five years). Abandoned land resulting from shifting cultivation is not included in this category. Data for arable land are not meant to indicate the amount of land that is potentially cultivable. Arable land is a category of agricultural land, which, according to Food and Agriculture Organization's (FAO) definition, additionally includes land under permanent or perennial crops, such as fruit plantations, as well as permanent pastures, for grazing of livestock. In 2008, the world's total arable land amounted to 1,387 Mha, and 4,908 Mha was classified as "agricultural land."
Although constrained by land mass and topology, the amount of arable land, both regionally and globally, fluctuates due to human and climatic factors such as irrigation, deforestation, desertification, terracing, landfill, and urban sprawl. Researchers study the impact of these changes on food production.
The most productive portion of arable land is that from sediments left by rivers and the sea in geological times. In modern times, rivers do not generally flood as often in areas employing flood control.
A paddy field is a flooded parcel of arable land used for growing semiaquatic rice. Paddy cultivation should not be confused with cultivation of deep water rice, which is grown in flooded conditions with water more than 50 cm (20 in) deep for at least a month. Genetic evidence published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) shows that all forms of paddy rice, both indica and japonica, spring from a single domestication of the wild rice Oryza rufipogon that occurred 8,200–13,500 years ago in China. Paddy fields are the typical feature of rice farming in east, south and southeast Asia. Paddies can be built into steep hillsides as terraces and adjacent to depressed or steeply sloped features such as rivers or marshes. They can require a great deal of labor and materials to create, and need large quantities of water for irrigation. Oxen and water buffalo, adapted for life in wetlands, are important working animals used extensively in paddy field farming.