Pakistan lies in Indus River basin with four major and many smaller rivers flowing into mighty Indus river, which is the longest river in South Asia . It starts from Tibet, China crossing through India into Pakistan and joins Arabian Sea near Keti Bandar in Sindh Province .
Pakistan is an semi agarian economy with 23 % share in GDP, services contributes most in economy . Pakistan is a semi arid to arid country , rainfall is not sufficient for crops to be grown without irrigation particularly in South Punjab , Sindh plain . Thus Irrigation system was developed in Pakistan making Indus Basin Irrigation System (IBIS), the largest continuous irrigation system in the world. The development of the irrigation system enabled Pakistan to irrigate /desert greening of once barren western Thar desert in Sindh and Cholisthan desert in south Punjab . At present Irrigation canals from barrages built at rivers irrigates more than 70%area of Sindh and Punjab plains and three District of previously barren land of eastern Balochistan(with no major river ). Output from these agricultural lands provided raw materials to Pakistan ‘s food processing and textile industries. As a result of Desert irrigation Thar desert in Pakistan is now confined to Indian border in East decreasing the proportion of Pakistani Thar desert to just 20%.
In 2005, Pakistan produced 21,591,400 metric tons of wheat, more than all of Africa (20,304,585 metric tons) and nearly as much as all of South America (24,557,784 metric tons), according to the FAO. The country had harvested more than 25 to 23 million tons of wheat in 2012.