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2013年9月9日 星期一

Outdoor Hydroponics without LED grow lights




Without fertile soil and abundant water, a farmer would seem to be missing the most essential tools of his trade. Hydroponics can help a struggling farmer grow an abundant crop even on a small parcel of land in a desert, on a rooftop, in a starving city — with no need for such luxuries as soil and rain. Two 14-year-olds from Swaziland recently won Scientific American’s inaugural Science in Action award by coming up with a plan to use hydroponics to provide food for their tiny country which is completely surrounded by South Africa.


“Over 80 percent of the vegetables consumed in Swaziland each year are imported from South Africa,” according to a video the two teenagers, Sakhiwe Shongwe and Bonkhe Mahlalela, created about their project. “Forty percent of the population relies on food aid.”

Besides a $50,000 prize and a year of mentoring from Scientific American, the teens will be flown to Google’s California headquarters in July to compete in the Google Science Fair. In an experiment comparing their biodegradable hydro system to soil cultivation of crops, Shongwe and Mahlalela found hydro gave them a 32 percent boost in yield, 180 percent faster plant growth and 114 percent greater profit margin.

Hydroponics uses nutrient rich water to feed plants, so good soil is not needed. Hydro systems can also be built so that they reuse that water, which makes them more efficient than irrigation. One of the main problems with using hydroponics to feed the poor is that often the systems rely on expensive pumps, nutrient mixtures, and other materials.

                                     
By using sawdust, chicken manure, and cardboard cartons the young Swazis found a way around the cost barrier. Using hydroponics to meet the needs of the world’s hungry isn’t a new idea, but the knowledge of how to set up a hydro system is not widely distributed. To address that knowledge gap, the Universidad Nacional Agraria – La Molina in Lima, Peru offers outreach and extension programs to bring the benefits of hydro to Peru. The university has an extensive demonstration farm on their campus located a 10 minute bus ride from downtown Lima. The farm showcases everything from fancy high end systems with all the bells and whistles to simple set-ups built from old roofing panels and wooden pallets.

Another organization involved in spreading hydroponic techniques is the Institute for Simplified Hydroponics. They provide educational materials on how to use waste materials to build hydro systems that can provide fresh nourishment, even for impoverished city dwellers with no land. For the urban poor, the cheapest foods available are often high-calorie and low-nutrient. Having a source of healthy, fresh produce can go a long way to reducing malnutrition.

                         

While she was living in Honduras, a neighbor and her built a hydroponic system using some wood, plastic sheeting and river sand. The biggest benefit her neighbor found to the system was that it allowed him to get seedlings started and grown up for transplanting before the free-range chickens could peck them to pieces. That allowed him to get a large number of healthy tomato seedlings started using less seed. The tomatoes, which he then planted in the soil, gave him a higher value crop than the corn and beans he usually grew in that area.


Hydroponics System from Chicfarm LED grower, http://www.chicfarm.net
                                             

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