Basically there are two ways by which we can reduce water for irrigation use:
Surface runoff: If the amount of water falling on the ground is greater than the infiltration rate of the surface, runoff or overland flow will occur

Transpiration is the evaporation of water from plants. It occurs chiefly at the leaves while their stomata are open for the passage of CO2 and O2 during photosynthesis. It also occurs at stems, flowers and roots.
Research confirms, that, by using magnetic water treatment systems (developed by Omni Environmental Group, for irrigating pea plants with magnetically treated water) significantly , reduced the water used in transpiration of pea plants. There was 32%, 18% and 13% reduction in transpiration by irrigating pea plant with magnetically treatment of tap water, 1500ppm salt water and 3000ppm salt water respectively compared with non-magnetic treatment of water.
Results of the studies confirms our Magnetic water treatment systems significantly increased in fresh weight 12.5% , dry weight by 22%. Similarly water productivity (produce/KL of water used) increased by 11% and 28% using potable water, saline water of 3000ppm, 1500ppm, 1000ppm and recycled water. For detailed information visit: www.waterforlife.net.au