Water is a critical input for food production and one of the major reasons for world-wide food shortage has been the progressive decline in usable water and erratic rain pattern experienced from time to time. Over exploitation of ground water and global warming affecting precipitation in the form of rains are twin problems facing to day's world. Over 80% of cultivation of world's farmland depends on rains and the productivity from these lands tends to be highly fluctuating year to year depending on timely rainfall. Water use in cultivation needs to be optimized and according to agricultural experts "supplemental irrigation" technique in rain fed areas with just one third of water used for full irrigation can increase land productivity significantly.
Gathering in Amman, Jordan, for a global conference on food security and climate change in dry areas, experts reported that improved irrigation techniques in rainfed cropping will allow farmers to more than double their wheat yields using only one-third the water they would use with full irrigation; the new methods have been shown to boost farmers' yields up to five-fold over those crops which relied on rainfall only. Such innovative strategies could provide a much-needed lift to livelihoods in dry areas in the developing world, home to almost 25 percent of the world's population. Regions most affected by drought and water scarcity are also disproportionately challenged by high population growth, climatic unreliability, frequent droughts, and widespread poverty, the experts said, citing figures from the Food and Agriculture Organization (FAO) of the United Nations.
The figures mentioned are really impressive and yield of wheat at 2.5 kg per cubic meter water under supplemental irrigation is significantly higher than 0.5 for rain-fed and 1 kg for fully irrigated lands. If resources required for establishing such water saving technologies in Asian and African countries are forthcoming from the rich nations, there is no reason as to why there should be any food shortage at all in this planet.