Tropes

WS_1452 01194.txt

Big, Smart and Green: A Revolutionary Vision for Modern Farmingwhat they re doing on Marsden Farm isn t organic. It not industrial, either. It a hybrid of the two, an alternative version of agriculture for the 21st century: smart, green and powerful. On this farm in Boone County, Iowa, in the heart of corn country, researchers have borrowed from both approaches, using traditional techniques and modern chemicals to get industrial yields but without industrial consequences. If the approach works at commercial scales, and there good reason to think it will, it might just be an answer to modern farming considerable problems. oewe wanted to show that small amounts of synthetic inputs are very powerful tools, but they re tools with which you tune the system, not drive it, said Adam Davis, a researcher with the United states Department of agriculture. The Marsden Farm experiment which is described in a study published Oct 10 In public Library of Science One, started in 2003, when Davis was a graduate student under agronomist Matt Liebman of Iowa State university. Liebman specialty is integrated pest management, or strategies that use nature to accomplish what typically done with pesticides, herbicides and synthetic fertilizer. It not a new idea, but it one that been neglected generally for the last several decades, as large-scale farming came to rely on simplified, chemically intensive and ultimately unsustainable approaches. For a while, these worked, but with high yields came big problems: the threat of catastrophic disease outbreaks in monocultures, an insatiable demand for nitrogen fertilizer, pesticide-resistant bugs and herbicide-resistant superweeds, and a new generation of crops designed to be drenched in toxic chemicals.''We have to figure out this fusion of industrial and organic. They've illustrated what it looks like. It's power and efficiency.''oewe have two choices now, said Liebman. oewe can double down, load more chemicals into the system, and get another decade of increasingly ineffective control or we can choose the path towards integrated management. Liebman, inspired in part by a pioneering Iowa farmer named Dick Thompson, wanted to bring integrated pest management back, but augmented with technology new tools. On 22 acres at Marsden Farm, his team planted three plots with different rotations of crops. The first followed a two-year rotation, alternating between corn and soybeans, as is customary in the region. It was managed the usual way with lots of chemicals. For the second plot, the researchers rotated over three years between corn, soy and oats, with red clover planted in winter. The clover, which absorbs atmospheric nitrogen, was planted between crop rows and plowed under as soil-replenishing oegreen manure in spring. On another plot, instead of red clover the researchers planted a fourth-year crop of alfalfa, which can be used to feed livestock. The animals manure came back as fertilizer. On these fields, the researchers still used herbicides and pesticides, but not the usual way. Rather than spraying them routinely over large areas Liebman team applied them only when necessary. oewe use low-dose products in the smallest quantities possible, he said. oewe re not against their use. What we re arguing for is using them as carefully deployed tactical options. Liebman called these applications oetherapeutic measures. Therapy wasn needed t often. Having different crops with different life cycles made it harder for weeds to grow. What might flourish among corn and soy, for example, was disrupted by oats. When red clover and alfalfa were mowed, weeds were chewed up before they flowered. As for insect problems, low pesticide use along with habitat provided by cover crops, allowed pest-eating bugs and birds to flourish. After eight years, Liebman and Davis used eight times less herbicide in the three-and four-year rotations than in the conventional plot, they report in the new study. Ecotoxicity in surrounding water was two orders of magnitude lower. Thanks to clover and alfalfa, the experimental plots also used 86 percent less synthetic fertilizer. Most important of all the experimental plots were as productive as the conventional. They produced just as much total crop biomass. When the researchers calculated the value of their environmentally friendly harvest it was every bit as profitable. oewe exceeded those goals not by pumping chemicals in, but by maximizing ecosystem services, Davis said. oewe re not throwing away those tools. They re very important. But you use a strong cropping system as the foundation for your agriculture. Then, when you need it, you tweak it a little bit with the inputs. Liebman and Davis said the system can be scaled up and applied to other crops. While the new study details were local, the essential underlying principle, of building a crop system around the ecological services it provides, is universal

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