Healthy soil and sustainable growing

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Greenhouse farming seen as water solution
http://www.abqtrib.com/archives/news04/092704_news_bright.shtml
September 27, 2004

Liquid gold.

That's what water could easily become as climates change, desert cities and
populations grow, and the precious resource becomes steadily harder to
find.

Overcoming the increasing scarcity of water will require all the
technological know-how the human race can muster.

Sandia National Laboratories is working with other groups on one possible
way to fight that problem. It's adding new technology to an old idea - the
greenhouse, said Ron Pate, a Sandia scientist.

"Water is already a source of major conflict in parts of the world," Pate
said. "It's a sleeper issue. As populations continue to grow in arid
regions, agriculture needs to find a way to meet the human demands. A lot
of people in the field are getting nervous about that."

With engineers' eyes, Sandia researchers are looking at ways to make
greenhouses cheaper and easier to run, while keeping an eye on the bottom
line of water conservation, he said.

They started studying the technology in August and will continue through
the winter, Pate said.

Increasing the use of greenhouses could save 35 percent or more of the
world's water supplies, because greenhouses use significantly less water to
grow more crops, he added.

The first step for the scientists is to collect data about the daily
operation of greenhouses, which they are doing at a research facility near
the New Mexico-Mexico border, said Gerry Yonas, another Sandia scientist on
the project.

"The goal is to make detailed measurements of all aspects of the greenhouse
and use that as the basis for computer modeling of things like specific
water use and optimum conditions for temperature, humidity, light," Yonas
said. "We want to see how we can make it better."

About 70 percent of the available water worldwide is used for agriculture,
with the remaining 30 percent going to cities and towns. Finding a way to
cut agricultural water use in half - while keeping farmers in business -
would be a major boon for future world populations, Yonas said.

"Cities and towns are playing with their 30 percent as much as possible,
doing what they can to conserve," he said. "You cut that in half and you
save about 15 percent. If you cut agriculture's use in half, you save 35
percent, and there's evidence we can save a lot more than that."

The scientists have put sensors all over the greenhouse - on plants, in
soil, on windows, on floors - all feeding information back to a central
computer that is collecting the data.

Eventually they hope to automate as much of the management as possible -
making the computer run the show. They also hope to find new materials for
building greenhouses that could save farmers a significant amount of money,
Pate said.

Greenhouse management has never been an exact science. Operators have
learned through generations of trial and error to find optimum conditions
to grow plants, Pate said.

"It's a technology that really came about in a more commercial way in
northern Europe," Pate said. "It's a way to extend the growing season in
places like Holland, which is a leader in the technology, and in places
like Canada."

Greenhouses are expensive to build and require a significant amount of
expertise to manage, which is why they haven't taken over in the United
States, except for luxury crops like flowers. But in desert areas like the
Southwest, there is a growing case for finding ways to make the technology
work, Pate said.

"Quality control is much better in greenhouse conditions," he said. "You
have better control over pests, better control over fertilizer and weather.
You can use a lot fewer chemicals."

In New Mexico, many farmers grow alfalfa for animal feed. Because it isn't
a high value crop, nobody in the United States has considered growing it in
a greenhouse before - but Mexico has, and the country has come in with
experts to help Sandia study the process, Pate said.

"About 90 percent of Mexico's land is high and dry, making it very hard to
water and grow crops," Yonas said. "They're far ahead of us in their
knowledge of advanced greenhouse management. They're showing us what they
know, and we're quantifying it."

Alfalfa uses a lot of water compared to other crops in the state, he added.

Convincing farmers to switch to greenhouses will still take some doing.
Governments or cities might be convinced to help, however, or even pay to
build greenhouses for the farmers in exchange for the saved water - which
could be leased or sold, Yonas said.

"We're still in the early stages and there are a lot of variables left to
study," he said. "Right now we're just trying to get our facts straight. We
want to find out what the realities are, do experiments and see how we can
realistically make a case for this technology."