Roughly one-third of Iran's total surface area is suited for farmland, but because of poor soil and lack of adequate water distribution in many areas, most of it is not under cultivation. Only 12% of the total land area is under cultivation (arable land, orchards and vineyards) but less than one-third of the cultivated area is irrigated; the rest is devoted to dry farming. Some 92 percent of agro products depend on water. The western and northwestern portions of the country have the most fertile soils. Iran's food security index stands at around 96 percent.
35% of the total land area is used for grazing and small fodder production. Most of the grazing is done on mostly semi-dry rangeland in mountain areas and on areas surrounding the large deserts ("Dasht's") of Central Iran.
The non-agricultural surface represents 53% of the total area of Iran, as follows:
39% of the country is covered by deserts, salt flats ("kavirs") and bare-rock Mountains, not suited for agricultural purposes.
An additional 7% of Iran's total surface is covered by woodlands.
And 7% is covered by cities, towns, villages, industrial areas and roads.
At the end of the 20th century, agricultural activities accounted for about one-fifth of Iran's gross domestic product (GDP) and employed a comparable proportion of the workforce. Most farms are small, less than 25 acres (10 hectares), and are not economically viable, which has contributed to the wide-scale migration to cities. In addition to water scarcity and areas of poor soil, seed is of low quality and farming techniques are antiquated.
All these factors have contributed to low crop yields and poverty in rural areas. Further, after the 1979 revolution many agricultural workers claimed ownership rights and forcibly occupied large, privately owned farms where they had been employed. The legal disputes that arose from this situation remained unresolved through the 1980s, and many owners put off making large capital investments that would have improved farm productivity, further deteriorating production. Progressive government efforts and incentives during the 1990s, however, improved agricultural productivity marginally, helping Iran toward its goal of reestablishing national self-sufficiency in food production.
Average annual rainfall is 800 mm but in Iran the annual rainfall is only 220 mm. Overall, Iran's soil is not well suited for large scale agriculture. About 12 percent of the country's total land area of 1,636,000 km² is cultivated. Still, 63% of the cultivable lands have not been used, and 185,000 km² of the present farms are being used with 50 to 60% capacity.
Both irrigated and rain-fed farming are used in Iran. In 2005, some 13.05 million hectares of land was under cultivation, of which 50.45% was allocated to irrigated farming and the remaining 49.55% to rain-fed system. As of 2013, the amount of cultivated land that is irrigated increased to 8 million hectares, while 10 million hectares remain rain-fed.