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global briefs
Urban Crops Can Have Higher Yields Than Conventional Farming
A new study led by Lancaster University researchers shows that urban gardens and hydroponics can thrive and may exceed the robu_s/AdobeStock.com yields of rural farms. Professor Jess Davies, project lead for the Rurban Revolution project that developed this study, says, “Urban food growing is often dismissed as something that cannot meaningfully contribute to food security.”
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The paper compiled studies on urban agriculture from 53 countries to find out which crops grow well in cities, what growing methods are most effective and which spaces can be used for growing. It turns out that urban yields for crops like cucumbers, tubers and lettuces can be two to four times higher than conventional farming. Cost efficiency remains an open question and important factor.
Most studies on urban agriculture focus on private and community gardens, parks and field growing operations. This one includes “grey” spaces in cities that are already built, but could be used for growing, such as rooftops and building facades.
Dr. Florian Payen, lead author and researcher from the Lancaster Environment Centre, says, “Surprisingly, there were few differences between overall yields in indoor spaces and outdoor green spaces, but there were clear differences in the suitability of crop types to different gray spaces. You can’t exactly stack up apple trees in a five- or 10-layer-high growth chamber.”
Concrete Made with Rubber Refuse
Concrete consists of water, cement and an aggregate such as sand or gravel. The aggregate has to be mined from the ground, and is now in short supply in many parts of the world, while discarded tires can be partially recycled, but are often burned or relegated to landfills.
Attempts to replace some of the aggregate used in concrete with crumbled, used tires has been stymied by a bonding problem because pores in the rubber fill with water when the concrete is first mixed, and become empty holes as the water evaporates and the concrete sets.
As reported in the journal Resources, Conservation & Recycling, scientists at Australia’s RMIT University have produced good-quality concrete in which all of the aggregate has been replaced with tire particles. They started with wet concrete in which all the aggregate is comprised of tire particles, then placed it in special steel molds as it set to place pressure on the concrete, compressing the particles and the pores within.
Once the concrete dried and set, the cement had bonded much better to the tire particles. When compared to previous 100-percent tire-aggregate concrete produced by conventional means, the preloaded concrete exhibited 97 percent, 59 percent and 20 percent increases in compressive, flexural and tensile strength, respectively.
WINTER WREATH WORKSHOP
DECEMBER 3 11AM–3PM
Sign up for a workshop to design a beautiful wreath using ribbons and natural materials gathered from our 386-acre organic farm.
$45 $50
Pre-Registration price per person/group
(includes one wreath) >RODALEINSTITUTE.ORG/EVENTS Day-of price per person/group (includes one wreath) time and space permitting
Families can also enjoy hot drinks around the fire pit and take free wagon tours. Ride with Santa from 11am-1pm!