More Crop for Every Drop

Space tech can make a difference in a grim water scenario.

The popular adage "Water water everywhere but not a drop to drink" truly reflects the impending serious water crisis facing India and many other nations across the world. In spite of the alarm raised by scientists in the Rio and UNISPACE - III World Summits and the warning from the World Water Commission, the world community is yet to evolve a global water vision for efficient management of available precious water resources in the world.
Even though the total amount of water in the world is an astronomical, 97.2 per cent of this resource happens to be non-potable saline sea water. Further, 75 per cent of even the available 2.8 per cent fresh water is locked up in ice caps and glaciers, which leaves less than 0.7 per cent of total available global water for human consumption.
With over 70 per cent of the annual rainfall being lost through evaporation into space and as surface runoff, availability of average per capita fresh water is no more than 8,400 cubic m per year, which will decrease to 4,800 cubic in by 2050 as the global population reaches 1.6 billion.
Even though the average per capita availability of water on a global scale is quite adequate, grossly uneven distribution of water which varies between 150 cubic m/capita [Saudi Arabia and Israel] to over 80,000 cubic m [Canada, New Zealand], many countries particularly in South Asia and Sub-Saharan Africa have turned out to be water-scarce countries.
India is already classified a water-scarce country with many states like Rajasthan suffering from acute scarcity of water. Torrid Zones Challenge
On an average 70 per cent of water is utilized for agricultural food production and 20 per cent for industrial use, which leaves just 10 per cent of the available fresh water for human consumption. Torrid zone countries like India, where the rainfall occurs primarily during three months in a year resulting in severe shortfall of soil moisture for eight months due to high transpiration rate, require a large amount of water for crop irrigation.
India, for example, accounts for over 50 million hectares of irrigation, which is about 20 per cent of the global irrigated land. Large-scale use of groundwater irrigation, which is almost twice as effective as canal irrigation, has resulted in the ground¬water table in most parts of India dipping by as much as 100-200 feet below the level just a decade ago. Water scarcity is worsened due to poor irrigation practices and excessive use of water and chemicals fertilizers, which have resulted in unacceptable increase of soil salinity and poor agricultural productivity.
The solution to the alarming water scarcity problem in India lies in initiating a sensible two-pronged attack, one for improving water availability, and the second by adopting appropriate water management practices in agriculture based on valuable inputs from the knowledge base now available.
Space technology, provides an excellent means of logging water inventory across the country due to its ability to provide reliable information on snow melt run off, groundwater availability, water storage capacity and siltation and sedimentation in reservoirs, tanks, rivers and dams.
It also greatly helps in judicious management and conservation of soil and water resources, location and development of water harvesting structures and in command area development, in addition to providing estimates of rainfall and soil moisture. With regular monitoring of soil salinity as well as flood and drought conditions using vegetation index derived from space remote sensing, it is now possible to employ grid-based precision farming techniques using GIS information to maximize agricultural production using optimal quantities of water and fertilizers. Advanced countries like USA are able to achieve food productivity of over five tonnes/ha through optimal utilization of water, fertilizer inputs and integrated pest management strategies using precision farming methods and space imageries from LANDSAT, IKONOSS and even Indian Remote Sensing Satellites.
Water scarcity is the biggest problem facing many parts of the world, far more severe than even the problem of providing food and energy security to the fast growing population. A determined knowledge-based approach aimed at detection, prediction, conservation and efficient utilization of water alone can produce more crop for every drop and meet the basic requirements of providing sufficient water for human consumption. We urgently need a world water vision to enable all living beings on earth to lead a comfortable life and save our planet from a serious water catastrophy.
-Prof. URRao