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April 18, 2012

 

 

·       No-till farming gaining traction in the US

·       Using maths to breed better plant varieties

·       New approach to molecular plant breeding

·       Promiscuous queen bees maintain diversity

·       Guerrilla gardeners sow seeds of social change

 

 

No-till farming gaining traction in the US

 

(AFP) – Indiana farmer Mike Starkey does not plow his fields and uses fertilizer only sparingly, but he is on the cutting edge of a growing trend in American agriculture.

 

Advocates of his "no-till farming" technique say it could provide the low-cost, environmentally-friendly crops the agricultural industry has sought for many years.

 

Starkey's cropland looks like a tangle of corn stalks, crimson clover and ryegrass, far different from the impeccably-plowed fields of most farms.

 

"Over a period of 12 years, we're now 100 percent no-till," said the corn and soybean farmer, who also is a supervisor with the Hendricks County Soil and Water Conservation District.

 

The biggest departure from traditional farming involves the plowing, also known as tilling.

 

Plowing aerates the soil, eliminates weeds and helps with nutrient recovery.

 

However, plowing also erodes the soil and kills part of the organic life that grows in it.

 

No-till farming helps to rebuild the "nutrient capital" of farmland that now is dependent on fertilizers, Starkey said.

 

The technique, also known as "conservation farming," started about 20 years ago by following the "three pillars" of the method: cover crops, no-till and crop rotation.

 

Cover crops refer to plants like clover, ryegrass and alfalfa that form a carpet to protect the soil from erosion while also trapping nitrogen from the air and storing it in nodules on the roots of plants to fertilize the ground.

 

In April, just before the sowing of seeds, weed killer is sprayed on the cropland.

 

"When we actually kill these legume plants, these nodules then become an organic source of nitrogen that breaks down much more slowly than commercial fertilizer," said Barry Fisher, a no-till farming expert for the US Agriculture Department's National Resources Conservation Service.

 

"That's a time release form of nitrogen... that will spoon feed the nitrogen to the corn crop coming here," Fisher said.

 

Cover crops maximize the use of the soil's natural fertilizers, which can be a better alternative than manufactured fertilizers sinking into groundwater after heavy rain, he said.

 

Direct seeding for cash crops requires special tractors that dig narrow furrows, inject the seeds and close the hole in one motion, without scarring the land.

 

No-till crops like corn and soybeans feed off the rich nutrients in decomposing plants from the previous season and from cover crops.

 

"Conservation tillage systems, with today's planting equipment, with today's technologies... have been yielding consistently the same" as traditional farming, said Tony Vyn, professor of agronomy at Purdue University, where the technique has been studied since 1975.

 

About 35 percent of US crops are grown with no-till farming, according to the US Agriculture Department. For soybeans, about half the crops are raised with no-till techniques.

 

The federal government is encouraging no-till farming by providing subsidies for cover crop seeds and the special equipment they require, which can run up to 50 percent of the cost.

 

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Using maths to breed better plant varieties  

 

(EurekaAlert!) – In the race to breed better crops to feed the increasing world population, scientists at The University of Nottingham are using maths to find out how a vital plant hormone affects growth.

 

Gibberellin is a hormone which plays a key part in development throughout the plant, from the root to the flowers and leaves. The hormone works within a complex network of molecules inside the plant, translating signals from the environment into responses in the plant so it can adapt and survive.

 

Many of the crop varieties developed during the global agricultural 'green revolution' of the 1960s were found to have genetic mutations in this important pathway. Now a team of scientists has applied mathematical approaches to understand how this 'green revolution' hormone works to control plant growth. They have then been able to show how these interactions result in changes in hormone levels that could be key to breeding improved crop varieties in the future.

 

Leading the research at Nottingham, Dr Markus Owen, Reader in Applied Mathematics, said: "We know that plants with low levels of gibberellin show drastically reduced growth, whilst adding gibberellin can significantly increase growth rates. Mathematical modelling has proved to be a powerful tool to help us understand how gibberellin works. Ultimately, this should help plant scientists to develop crops with improved growth, and hence to address problems of global food security."

 

A second piece of research in this area has looked at the gibberellin distribution along a growing root, a factor which also affects growth and development. A team led by Professor of Theoretical Mechanics at The University of Nottingham, John King, has used multiscale mathematical modelling to probe how the gibberellin signalling network controls root growth. Work by researcher Leah Band revealed that dilution of gibberellin in rapidly expanding cells can explain why growth finally ceases.

 

The study led by Dr Owen highlights the importance of interactions between several key feedback loops within the gibberellin signalling network. Professor King's team combined that signalling network with a model for the elongation of a root, to predict how DELLA proteins (key components within the gibberellin signalling network which normally suppress growth), increase along the root, which explains experimental observations of growth rates.

 

Both studies have just been published in the leading academic journal Proceedings of the National Academy of Sciences of the United States of America (PNAS).

 

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New approach to molecular plant breeding

 

(USDA-ARS) – A U.S. Department of Agriculture (USDA) scientist has shown researchers and plant breeders a better way to handle the massive amounts of data being generated by plant molecular studies, using an approach that should help speed up development of improved crop varieties.

 

Jean-Luc Jannink, who is with the Agricultural Research Service (ARS) Plant, Soil and Nutrition Research Unit at the agency's Robert W. Holley Center for Agriculture and Health, in Ithaca, N.Y., has demonstrated that by using a statistical approach known as Genomic Selection (GS), scientists can capture and exploit more of the data produced by the growing number of studies focused on DNA sequences found in plant genomes. GS is currently used in cattle breeding.

 

ARS is the principal intramural scientific research agency in USDA. This research supports the USDA priorities of improving agricultural sustainability and promoting international food security.

 

Scientists and plant breeders increasingly use molecular tools to develop improved crop varieties. By identifying genes associated with desirable traits, they don't have to wait to observe crops grown from seeds.

 

But molecular tools require analyzing massive amounts of data, and important traits like drought tolerance and yield are the result of the combined actions of multiple genes, each with a small effect. These genes are called quantitative trait loci (QTLs), and the conventional Marker-Assisted Selection (MAS) approach to handling molecular data has limited power to detect small-effect QTLs and estimate their effects.

 

Jannink's recommended GS approach exploits more data by including all of the small-effect QTLs and estimating the effects of all of the known genetic markers in a plant population.

 

Jannink and his colleagues recently constructed statistical models, using both GS and MAS approaches, and compared how well they could predict values associated with 13 agronomic traits in crosses made from a "training population" assembled for the study. They gauged the model's accuracy by comparing their predictions with field observations of 374 lines of wheat.

 

The results showed the GS approach was more accurate at predicting trait values. Jannink had similar success in a study using oats. Both studies were published in The Plant Genome. The work is expected to speed up molecular breeding efforts and should prove extremely useful, given the pace of advances in DNA technology.

 

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Promiscuous queen bees maintain diversity

 

(ScienceDaily) – By mating with nearly 100 males, queen bees on isolated islands avoid inbreeding and keep colonies healthy. The results, published in the current issue of PLoS ONE, focused on giant honey bee colonies on Hainan Island, off the coast of China. Since these bees have long been separated from their continental cousins, it was thought that the island bees would be prime candidates for inbreeding as well as having very different genes, said Zachary Huang, Michigan State University entomologist.

 

"We believed that the island bees would show evidence of the founder effect, or random genetic changes in an isolated population, on a unique sex determination gene from the mainland bees," he said. "At first we were surprised when we couldn't document this effect. Looking at it further, I asked myself, 'Why didn't I think of this before?'"

 

When compared to bees, humans have a rather simplistic sex-determination process. In females, the two sex-determination chromosomes are the same, and in males the two chromosomes are different. With bees, however, the combinations of complementary sex determination genes, or CSDs, determine the sex and the societal role of the bees.

 

One particular gene can have alleles -- the "flavor" of genes. In humans, they dictate hair and eye color. In bees, though, they are responsible for creating females (worker bees), fertile males (that mate with the queen) or infertile males (diploid males which serve no purpose).

 

The voila moment came once Huang estimated the bees' mating habits and the potential of CSD allele combinations. That's when he understood why he couldn't confirm the founder effect. Keeping the CSD mix diverse is one of the keys to maintaining a healthy hive, he said.

 

The island queens carry around 40 CSD alleles. Since they mate with nearly 100 males -- each also harboring around 40 alleles -- the high number of healthy genetic combinations keeps the gene pool diverse. By using natural selection to create healthy offspring, the bees perpetuate a healthy colony.

 

In comparison, if the island bees adopted the breeding habits of fire ants, with queens mating with a single male, inbreeding could wreck the off-shore claves or distinct populations of bees. The devastating change would reduce the fitness of the hive, decreasing the female workforce, as well as lowering the number of mating males.

 

What would be left would be an unhealthy hive with higher numbers of diploid or infertile males, with the same alleles, Huang said.

 

By extending his research beyond Hainan Island, Huang found evidence that showed that the island wasn't an isolated case.

 

"We failed to find any clustering of the bees' CSD alleles according to their geographical origin; the Hainan and mainland bees did not form separate clades," said Huang, whose research is supported by MSU AgBioResearch. "Previously published CSD sequences also failed to show any unique clade-forming in the Philippines and Malaysia."

 

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Guerrilla gardeners sow seeds of social change

 

(The Washington Post) -- “Let’s throw some bombs,” a young woman calls out, waterproof floral purse swinging on her shoulder and Laura Ingalls braids flying behind her as a band of 25 followers cheer, “Cool!”

 

They rush toward a drab vacant lot in Shaw. Some climb up onto the back of a truck to get better aim at their target. But these bombers aren’t likely to appear on any terrorist list or even get arrested. They’re throwing “seed bombs,” golf-ball-size lumps of mud packed with wildflower seeds, clay and a little bit of compost and water, which they just learned to make at a free seed-bombing workshop for Washington’s guerrilla gardeners.

 

The benign bombing is part of a larger phenomenon known as activist gardening that is taking off this spring in cities such as Portland, Detroit, Baltimore and the District, where young urbanites are redefining the seemingly fusty pastime as a tool for social change. This is civil disobedience with a twist: Vegetable patches and sunflower gardens planted on decrepit medians and in derelict lots in an effort to beautify inner-city eyesores or grow healthful food in neighborhoods with limited access to fresh food.

 

“Guerrilla gardening is urban gardening and food justice. It’s just this really cool mix,” says Emmy Gran, 25, who is teaching seed-bombing in a floppy sun hat at a recent Saturday morning workshop in the courtyard of Old City Green, a gardening store in Shaw. “But it’s controversial, too. If you see an abandoned, neglected lot and you decide to do something about it by planting vegetables and herbs, are you an occupier? It’s kind of radical, in some ways.”

 

And every radical movement needs graffiti. Gran hauls out her Cuisinart to make the green “spray-paint” required for gardening activism’s biodegradable moss graffiti. Ingredients: moss, a half teaspoon of sugar and beer or yogurt which, when blended, will stick to walls. (“You can also use buttermilk,” she adds.) With a light rain starting to fall, the group walks over to a curb near the garden store and uses the gloppy mixture to write “Nourish, Grow, Shaw” in big, moss-green letters.

 

Activist gardening is the latest face of social justice in the District. Forget living in a tent in McPherson Square. Instead, try pulling on muddy work boots and hauling fertilizer and mulch to a forlorn lot, then persuading your housemates to get off their iPads and go outdoors to plant snap peas and garlic. The group at the workshop includes former Peace Corps volunteers, environmental activists, plaid-ensconced hipsters and social justice workers, all eager to learn more about subversive or sneaky gardening, as it is also known.

 

“It’s all a lot less devious than it seems,” says Ellen Abramowitz, 22, who works for the Alliance to Save Energy, a nonprofit group that educates schools about energy efficiency. “Besides, who doesn’t love flowers?”

 

 One flower at a time

 

Gran tells her students — most of whom were born in the 1980s — that guerrilla gardening dates from the late-1960s establishment of People’s Park in Berkeley, Calif., when a disused patch of land near the University of California campus was co-opted by the community and reimagined as a public green. Today, she says, it takes place in more than 30 countries, with much of the activity documented on the British-based Web site guerrillagardening.org. It has spread in the United States in recent years, spurred by the “green” movement and the increased demand for locally grown, healthful food.

 

“I think it’s also a democratic statement and an experiment in re-creating space,” says Columbia Heights environmental consultant Tristanne Days, 24, as she carefully assembles seed bombs. “We’re making the city what we want.”

 

They’re doing it one flower at a time. The bombs will — in theory — bloom into bachelor’s buttons and baby’s breath, forget-me-nots and marigolds when the truffle-size balls hit, then expand. It also helps if there’s a healthy spring rain, said Scott Aker, head of horticulture for the U.S. National Arboretum. If the bombs are launched into a sunny space where there’s not too much other vegetation present, then he gives the seeds a 70 percent chance of blooming. “But either way, it sounds like great fun,” Aker says. “On your commute, you can toss one out the window.”

 

District police say that guerrilla gardening technically constitutes unlawful entry, a misdemeanor. But, says D.C. police spokeswoman Gwendolyn Crump, “nothing like this has come to our attention.” Although there have been reports of gardens being bulldozed to make way for development, gardeners say the issue of small-scale gardening is typically hashed out between property owners and the people doing the planting.

 

 Permits for planting

 

Not everyone at Gran’s workshop is a guerrilla gardener. Some of the young people attending the class — run by Knowledge Commons D.C., an organization that provides free public workshops on a variety of subjects — have secured permits for their plots.

 

This spring Sarah McLaughlin, 25, and her boyfriend Josh Singer, 31, started a community “parken” on a 2.7-acre parcel of unused land north of Howard University. They named it Wangari Gardens after Wangari Maathai, the Nobel Prize-winning Kenyan environmental activist. (Although it took months, Singer was able to obtain a public-use permit from the Department of Transportation, which oversees the land, to garden there.)

 

“We’re a real D.C. love story,” McLaughlin says with a laugh as Singer puts his soil-stained arm around her after a long day of gardening. The couple fell in love at the Occupy D.C. camp in McPherson Square, where they were both living this past fall. Singer works for D.C.-based nonprofit group Casey Trees, which helps local schools and urban communities plant trees. McLaughlin is a manager for Old City Green and teaches an after-school garden and nutrition program at D.C. Prep Public Charter School in Northeast.

 

“We saw the land near where we have a group house, and we wanted to use green space to build community,” says Singer, who’s wearing an “I Dig Trees” T-shirt under his Carhartt jacket. So far, McLaughlin and Singer have helped the community plant 59 garden plots in Wangari Gardens, each tended by neighbors who live nearby and pay annual dues to grow food and flowers in a raised garden bed with advice from experienced gardeners. (On a recent visit to Wangari, several longtime residents said they were happy with the garden because the land had been vacant for so long.)

 

Singer has put $3,000 in soil and other supplies on his credit card. But he hopes the garden will flourish and that he will eventually obtain sufficient funding and grants to add a dog park, a butterfly/native plant garden and an outdoor classroom.

 

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