Agriculture engaged 44% of the economically active population in 1999. Agricultural production increased by an annual average of 4.4% during 1990–2000, accounting for 26% of GDP in 2001. The development of a huge irrigation network covering two-thirds of the total cultivated area—together with massive land reclamation projects—has made possible the farming of vast tracts of previously barren and unusable land. The Indus Valley of Punjab is Pakistan's agricultural heartland. There are two principal growing seasons: the kharif season starts between April and June and ends between October and December, while the rabi season starts between October and December and ends during April or May. Grains constitute the most important food crops, with wheat, rice, corn, and citrus the major products. Cotton, the most important cash crop, generates more foreign trade income than any other export item. Cotton production suffered in the late 1990s from leaf curl virus. In 2001/02, production totaled 8.3 million bales. Rice, sugarcane, tobacco, rapeseed, and mustard are also large export earners. Rice covers 11% of all cropland—production in 2001/02 totaled 3.88 million tons.
Improved government policies over the past decade have made Pakistan a net exporter of guar products, tobacco, cotton, and rice. Other major agricultural exports include molasses, fruits and vegetables, guar and guar products, and tobacco. Principal crops with 1999 output (in thousands of tons) were wheat, 17,790; sugarcane, 53,104; and rice, 6,900. Production of sunflower seed amounted to 120 tons in 1999. Other crops include millet, barley, sesame, flax, groundnuts, mangoes, citrus fruits, and vegetables. Opium poppies are grown in the North-West Frontier Province (with an estimated 95 tons produced in 2001), government efforts to stamp out the opium and heroin trade have helped reduce production by over 95% since the mid-1980s.
Farming production remains limited by primitive methods, and mechanization is uncommon. The introduction of improved wheat and rice varieties has met with some success, although the greatest impact on agriculture has derived from the Indus basin irrigation schemes, which by the 1970s had provided Pakistan with the largest irrigated network in the world. The availability of water has made possible increased use of chemical fertilizers, with the most intensive consumption occurring in cotton production. The government has instituted soil conservation, farm mechanization, land reclamation, and plant protection programs.
To increase smallholders' equity and provide further incentives for agricultural improvement, the government decreed in 1959 that the maximum holding for any person should be 200 ha (500 acres) of irrigated land or 400 ha (1,000 acres) unirrigated. Land in excess of these amounts was acquired by the government and paid for in interest-bearing 30-year bonds. In March 1972, the maximum permissible size of a holding, measured in terms of production index units, was reduced by two-thirds, with the government empowered to confiscate without payment all excess land for free redistribution to landless peasants and small tenants. To help the new landowners, the government provided loans for purchase of seed, feed, and bullocks. In accordance with a statement of national agricultural policy issued in 1980, the Agricultural Price Commission was established to provide incentives to Pakistani farmers through higher prices for farm products.