Suzanne Stone, a doctoral candidate in the College of Agricultural & Environmental Sciences, studies organic farming methods

Organic agriculture is a method of farming that avoids the use synthetic pesticides, synthetic fertilizers, and genetically modified organisms, which may have negative affects on human and environmental health, in favor of practices that build healthy soils and promote sustainable food production.

So why isn’t all food grown organically?

Suzanne Stone, a doctoral candidate in the College of Agricultural & Environmental Sciences, explains that the problem actually has to do with the low yield typically seen from organic farming methods compared to conventional framing methods.

“More than 300 published studies show that organic farming yield averages about 30 percent lower than conventional farming,” she says.

“That’s why some people say, ‘Organic can’t feed the world.’”

But according to Stone, the science behind the conventional versus organic debate may be biased.

“Almost all modern plant varieties that we grow today were bred for high-input, conventional agricultural systems.”

In fact, studies show that the top yielding varieties in organic systems are not always the top performing varieties common to our conventional farms.

One study even found that by breeding specifically for organic conditions, yield was increased by about 30 percent.

This research led Stone, under her co-advisors Dr. George Boyhan and Dr. Cecilia McGregor, to work toward breeding a variety of organic watermelon plant that can produce as much fruit as conventional varieties.

“Watermelon is a major industry in the South,” Stone says. “ We produce 61 percent of the nation’s watermelon, yet only 25 percent of the nation’s organic watermelon.

Furthermore, organic watermelon nationwide is just 1 percent of the total watermelon industry.

“As an optimistic and ambitious graduate student, I hope my research can help change that.”

Weeds, Stone explains, are the greatest threat to watermelon yield due to the plants being weak weed competitors (the sprawling vines make both conventional pesticide application and hand-weeding in organic plots nearly impossible for most of the growing season).

“Weed control is definitely the most significant barrier to the adoption of organic practices in watermelon,” says Stone.

“To address this challenge, I have been breeding watermelon to be compact in growth habit while still producing large, high quality fruit.”

The varieties she has developed require half the field space of traditional vining watermelon.

Because the vines don’t sprawl, row middles can remain accessible for season-long weeding, mulching, and repetitive harvests.

“Field experiments show that compact plants require 15 to 25 percent less time to hand-weed when organic weed control is conducted over the entire growing season,” explains Stone. “Our experiments also show that weeding just until flowering and fruit set begins results in the same yield as weeding the whole season; this partial season weeding strategy can save organic growers 62 percent in labor costs.”

“We know already that these compact varieties can produce fruit of similar size to traditional vine-types; I anticipate that these compact varieties can increase per-acre yield dramatically.”

Stone will have her answer this summer when she evaluates replicated trials for the first time.

“My husband and I came to UGA together to work on our PhDs [Horticulture and Wildlife Biology, respectively] because we wanted to work with professors that are the leaders in their fields. We will both be graduating in May.”

After graduation, Stone will take a plant breeding position in the vegetable seed industry.

“During our time here we have had two kids, a daughter Daisy, and a son, James. It’s been a wild ride, and we have loved raising our family in Athens and studying under the best professors at UGA.”

“We have received excellent training at UGA and look forward to representing our school well as we enter into the next phase of our careers.”


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