RDO showcases sustainability practices during farming tour
As the 2015 potato harvest winds down, RDO employees are looking at the season’s successes in sustainable farming methods that began two decades ago. A media tour of RDO potato fields Tuesday was designed to show that the company has scaled back on its use of pesticides, engaged in crop rotation that puts nitrogen back into the soils and reduced the number of aerial crop applications by 30 percent in the Park Rapids area on 13 percent of its acreage. “Our continued goal is to further optimize applications on more areas,” the company indicated.
RDO has invested in more growing areas to extend its crop rotation from three to four years, said Nick David, RDO midwest agronomist, and Joel Steffel, Park Rapids farm manager. The company is using potato varieties that require 50 percent less nitrogen than the Russell Burbank variety that’s been the hallmark of local potatoes. The moves have resulted in a 40 percent reduction in phosphorus use and 10 percent reduction in nitrogen use in Park Rapids since 2011, company officials said. The company has also planted 110,000 trees and 600 acres of pollinator seed to foster habitat for bees, monarch butterflies and other pollinators, the company indicated. It uses 60 different varieties of pollinators such as milkweed. “You can hear the hum of bees” said Steffel with a smile. Cover crops cut down on wind erosion, he added. But it’s the 1,000 acres of mustard that most excites David. The pungent crop repels insects and, when ground up, adds a biomass mixture that benefits the soil and the potato crop, David said.
“We’ll use as much mustard as we can use, up to 5,000 to 10,000 acres,” he said. The mustard is planted once the peas come out. Peas? The short-season crop is added to the crop rotation that also includes corn, wheat and dried beans, and of course, the potatoes. Ground into biomass, it produces “green manure.” RDO agronomists have experimented with cover crops for the past two decades to learn which crops build up the soil naturally. Some produce nitrogen, some with massive taproots move moisture around, like rye, others move phosphorus; some are disease suppressants; others are weed suppressants, David said. Cover crops like rye control erosion and survives the winter. Strong roots 18 inches or more hold the ground intact. “Obviously it’s to be good stewards of the land.” David said. “We don’t want our organic matter to blow away every spring. This is fantastic wind control.” The company isn’t throwing out seeds willy nilly. The rye is taking up water and nitrogen that are sucked up in the fibrous root system. It will germinate down to 32 degrees. “In some cases significant amounts of nitrogen,” he said. “We turn this under and the famer that tills it in, the microorganisms go to work on the soil and are released when it (the plant) dies.”
In some cases rye is seeded in with the potatoes. Cover crops are a big deal, David said. Oats grow even quicker than rye. RDO has planted sunflowers, peas and radishes to replenish depleted soils and studied their effectiveness. “It was quite the salad out there,” he said. “We’re not just throwing something out there. We have a purpose. “Our goal is to cycle nutrients to make them available for plant production.” Sequestering nutrients in the form of amino acids keeps them in a form that doesn’t leach through the soil. For the past 20 years, the company has done lots of soil sampling and drawn maps of its leased fields. In a controversial move the company sought to acquire more land in the Hubbard County area last spring. That met with resistance from the Minnesota DNR and opponents. The purpose of the additional land was not to plant more potatoes, but to add more land into the crop rotation and increase the number of potato crops a piece of ground seeds, Steffel said. Once the soil maps are drawn, the company advises the coops what crops would work best. They are not necessarily potatoes.
“If it needs a little bit more nitrogen for some reason, we do it,” David said of adding fertilizer. The reduction in spraying has been beneficial to both the company and neighboring farms. “Why would we want to spray more than we need to?” asked communication specialist Anne Struthers. “Because those are costs” she added. “If you don’t need it why use it? It defies business logic.” State of the art equipment and application methods have minimized the potential for drift or exposure to nutrients, irrigation or crop protection applied to fields. Drop-down, low pressure nozzles have minimized the amount of water used, used it more efficiently and reduced evaporation the company said. RDO plants 38,000 acres of potatoes in North Dakota, Minnesota, Wisconsin and Nebraska.
GPS units on many tractors ensure properly located seeds and are used once again for the harvest. The crops such as rye are incorporated back into the soil as biomass and to control the soil-borne fungus that attacks potatoes. And the local sandy soils don’t matter. “The goal is to cycle nutrients to make them available for plant production,” David said. “If they’d develop a potato plant that fixes nitrogen, I’d be very, very grateful,” he said.