In regard to its influence upon crops, irrigation has not brought new crops but it has encouraged changes in spatial distribution and in the relative importance of various crops. High-value crops show higher concentration in the Divisions with higher irrigation intensity and especially in those with perennial water supplies. Low value hardier crops are concentrated either on unirrigated areas or in the divisions having low intensity of irrigation. Cash crops are usually favoured on medium and large farms, provided the required moisture is available. As a whole, throughout Pakistan, rabi crops occupy much mare area than the Kharif crops. This is contrary to the availability of water since water is abundant in summer but scarce in winter. Three factors appear to be responsible for this: (1) water is used more efficiently in winter, primarily due to lower evapotranspiration: (2) crops grown during winter (rabi) are more valuable in terms of water and labour input; and (3) since water supplies are controlled by the Government, the farmers can irrigate only after a fixed interval of time regardless of crop requirements (17). Under the above mentioned conditions, the farmers do not take the risk of a higher investment in high-value sensitive crops. Besides, the traditional conservatism of the cultivator is also a hindrance in developing an optimum cropping pattern and in switching to the crops which pay more (1).