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 but less than one-third of the cultivated area is irrigated; the rest is devoted to dryland farming. Some 92 percent of agricultural 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.

Taxation in Iran is levied and collected by the Iranian National Tax Administration under the Ministry of Finance and Economic Affairs of the Government of Iran. In 2008, about 55% of the government's budget came from oil and natural gas revenues, the rest from taxes and fees. An estimated 50% of Iran's GDP was exempt from taxes in FY 2004. There are virtually millions of people who do not pay taxes in Iran and hence operate outside the formal economy. The fiscal year begins on March 21 and ends on March 20 of the next year.