Due to the increasing demand for food and fibre by its ever-increasing population, the pressure on fresh water resources of Pakistan is increasing. Optimum utilization of surface and groundwater resources has become extremely important to fill the gap between water demand and supply. At Lahore, Pakistan 18 lysimeters, each 3.05 m × 3.05 m × 6.1 m deep were constructed to investigate the effect of shallow water tables on crop water requirements. The lysimeters were connected to bottles with Marriotte siphons to maintain the water tables at the desired levels and tensiometers were installed to measure soil water potential. The crops studied included wheat, sugarcane, maize, sorghum, berseem and sunflower. The results of these studies showed that the contribution of groundwater in meeting the crop water requirements varied with the water-table depth. With the water table at 0.5 m depth, wheat met its entire water requirement from the groundwater and sunflower absorbed more than 80% of its required water from groundwater. Maize and sorghum were found to be waterlogging sensitive crops whose yields were reduced with higher water table. However, maximum sugarcane yield was obtained with the water table at or below 2.0 m depth. Generally, the water-table depth of 1.5-2.0 m was found to be optimum for all the crops studied. In areas where the water table is shallow, the present system of irrigation supplies and water allowance needs adjustments to avoid over irrigation and in-efficient use of water.

crop yield, evapotranspiration, groundwater, irrigation,lysimeters, maize, plant water relations, salinity, soil waterpotential, sugarcane, sunflowers, water requirements, water table, wateruse efficiency, waterlogging, wheat, Pakistan, Helianthus annuus,Saccharum, Saccharum officinarum, Sorghum, Trifolium alexandrinum,Triticum, Triticum aestivum, Zea mays, Helianthus, Asteraceae,Asterales, dicotyledons, angiosperms, Spermatophyta, plants, eukaryotes,Poaceae, Cyperales, monocotyledons, Saccharum, Trifolium,Papilionoideae, Fabaceae, Fabales, Triticum, Zea, South Asia, Asia,Developing Countries, Commonwealth of Nations, corn, watering, FieldCrops (FF005) (New March 2000), Plant Water Relations (FF062), PlantProduction (FF100), Soil Physics (JJ300), Water Resources (PP200)

• Journal Article

• Water Supply, Sources and Agricultural Use