About 69% of Tonga is agricultural land, including small amounts of permanent pasture. With increasing population pressure on the land, more land is being intensively cultivated and less is available for fallow. The use of fertilizers, high-protein strains of corn, and similar methods to improve the efficiency of land use has become increasingly necessary.
According to the constitution of 1875, all the land in the kingdom belongs to the crown and cannot be alienated. Much of it, however, consists of hereditary estates that were bestowed upon various chiefs, who lease the lands to farmers at a nominal annual rent. Since 1890, the crown has been responsible for the collection of rents and the granting of allotments.
On reaching the age of 16, every Tongan male taxpayer is entitled under the constitution to a tax allotment of one api (3.34 ha/8.25 acres). These allotments are hereditary, pass from generation to generation in accordance with the law of succession, and may not be sold. A tenant may be ejected for nonpayment of rent or for failing to comply with the planting regulations, under which every Tongan holder of a tax allotment is legally required to plant 200 coconut trees, which he must keep free from weeds. In recent years, however, population increases have made it impossible to guarantee the api to all those entitled to one.
Principal subsistence crops are yams, taro, sweet potatoes, and manioc. Estimated production in 1999 included coconuts, 25,000 tons; sweet potatoes, 5,000 tons; cassava, 28,000 tons; oranges, 3,000 tons; and bananas, 1,000 tons. Vanilla beans have become an important cash crop, especially on Vava'u. Agricultural products accounted for 67% of exports in 2001.