Feeding the increasing world population has been a major agricultural topic, but the water needed to produce the volume of crops necessary to feed the population has been more of a behind-the-scenes topic.

"Within the next 40 years, the world will have an additional 2.5 billion mouths to feed, most of them in developing countries across Africa, Asia and South America. Global crop production will have to double to feed this growing population unless we learn to reduce waste and use water more efficiently. Given that one liter of water is needed to produce one calorie of food, it will take up to 6,000 cubic kilometers of additional water annually to feed another 2.5 billion people. This is almost twice what is used today and is not sustainable," reported the International Water Management Institute (IWMI) last November.

In investigating this series of articles that began in AgProfessional's January issue, it became apparent that improving the water delivery infrastructure in developing nations is the focus outside the U.S.

The improvement in crops' genetics for better water utilization has been almost an afterthought — because it probably will involve biotechnology and European countries are still opposed to crop biotechnology. "New crop varieties that tolerate extreme conditions, like drought and flooding, can also help" is all the credit that IWMI gives to genetically improving crops.

IWMI contends, "The best bet for Asia lies in revitalizing its vast irrigation systems, which account for 70 percent of the world's total irrigated lands."


GROWING THE SAME FOODS

Farmers of the world are going to be asked to continue growing the same crops, whether they are "water guzzlers" or not. People of the world aren't going to change their base diets. For example, Asians are not going to quit eating rice, and the U.S. population isn't going to replace corn-based foods because of water shortages to grow water-demanding corn.

Production of crops using less water is being left for scientists to solve in those countries such as the U.S. that have accepted biotechnology as a logical solution to improve agricultural production.

The Kansas Grain Sorghum Board notes that the future of agriculture likely will include additional planting of water-use efficient crops, and the organization sees sorghum, which "is one of the most drought-tolerant cereal crops currently under cultivation," being planted in more acres.

Current sorghum varieties perform well in the warmer semi-arid parts of the country with Kansas being a northern edge to the majority of volume sorghum production. Sorghum seed companies are doing extensive research to produce varieties that could be grown farther north and replace corn in many areas of the country. Corn requires much more water to produce a crop.

California growers recently were told to look at growing "water-saving crops," and the Pacific Institute called on farmers to quit growing "water-intensive crops like rice, cotton, corn, wheat and alfalfa." The institute contends that some vegetable and fruit and nut trees are more water efficient, require less water and can be irrigated in a more efficient manner than the conventional row crops and forages.

Similar calls for other crops around the world to be grown more efficiently is typified by a report out of India that contends sugar cane, which is a major crop in the country, can be grown with 75 percent less water than typically used simply by changing irrigation management practices and the types of fertilizers and pesticides applied. Lower yields with less inputs is the theory, which doesn't solve the food crisis of the future, but does yield a higher income to farmers as water becomes scarce and is priced higher.


RESEARCH PROGRESSING

Last month's water management article was mainly about breeding better water-utilization, water-optimization corn and soybeans. Research with numerous other crops is going on worldwide. A prime example is in Israel where Tel Aviv University researchers are "genetically modifying plants' root systems to improve their ability to find the water."

"We are increasing a plant's efficiency for water uptake. Plants that can sense water in a better fashion will be higher in economic value in the future," Amram Eshel, Ph.D., a lead researcher, said.

Plant roots that can seek out and utilize water more efficiently than other plants are also the focus of research into cultivating new crops — some of them being weeds. turned into crops. As every farmer knows, crops might shut down from stress, but some weeds just keep growing. If those weeds have a commercial market, then they could replace less efficient crops or result in arid acres becoming production acres.

New Mexico State University (NMSU) has at least two research projects underway. One would allow weeds to be used as a biofuel and another is looking at weeds as livestock feed. Crop production on these marginal acres leaves more productive acres for human foods.

"Amaranthus species with small seed size, wide adaptability, highly scavenging root systems, C4 photosynthetic pathway and highly competitive nature are one of the noxious weeds in the U.S. A number of traits like higher photosynthesis rate, reduced perception of nearest neighbor, pest and disease resistance, drought tolerance, optimal nitrogen acquisition and utilization, which are desired in a biomass crop, are anticipated in Amaranthus spp.," a NMSU research team reports.

Other NMSU researchers are looking at the potential for kochia to be grown as a water-efficient forage crop for feeding livestock if kochia toxicosis can be overcome. Instead of breeding for water utilization, plant breeders will be looking at breeding out the toxicants. This weed already has the ability to grow in harsh conditions of the U.S.


CHANGE WILL BE SLOW

Growing crops according to the amount of water available will change the world from the way we know agriculture today. The examples included here are just a sampling of what is going on in research related to efficient cropping with less water. 

It appears change will be a slow process as science drives new technology in biotechnology and the world's population eventually recognizes it must accept water-optimization crops to have food in their mouths as well as drinking water. Less water for agriculture means more water for human consumption.

As the spigot is turned off for some types of crop production in various areas of the world, farmers will find alternative crops. The science also appears to be developing water optimization crops that are economically feasible to allow farmers to earn a profit. Change isn't going to be easy, but it is in progress.


Editor's Note: This is the last article in a four-part series on the issue of water management and its impact on agriculture around the world.