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Air-drills suited for seeding corn Don't worry about row spacing |
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Don't worry about row spacing when planting grazing or silage corn with a solid
seeding system.
Seeding corn with an air-drill or air-seeder usually raises questions around
row spacing. With most grain and table corn planted with a row planter on 15
to 30 inch row spacing, many grazing corn growers have wondered if seeding with
an air-drill would work, or if they should block off every other run in their
air-drill to simulate a row planter. "The majority of grazing corn acres are sown with an air-drill or air-seeder. It can be a bit intimidating if you are a first time grower, but after the first year, they see that seeding and growing grazing corn is pretty easy," says Rob Ripley, Monsanto seed and technology development representative in Saskatoon. In fact, a recent survey by Monsanto found that 77 percent of its growers used an air-seeder or air-drill for seeding grazing corn. Over the last three to four years of grazing corn development, seeding rate and stand establishment has moved away from an emphasis on row spacing to the realization that targetted plant population is the critical factor. Ripley says that any common row spacing will work with an air-seeder or an air-drill, and that many growers use row spacings from seven to 12 inches quite successfully. And, hitting the targetted plant population of 30,000 seeds per acre is crucial in stand establishment. For first time growers, the wide spacing between corn plants at emergence can be disconcerting. On an eight inch row spacing with 30,000 seeds per acre, the distance between kernels is approximately 26 inches, and at a 10 inch row spacing, the seeds are 21 inches apart (see Table 1). That means there is usually only one plant per 1.5 square feet.
Thiel grew Dekalb brand DKC27-12 grazing corn for the first time in 2004, and sowed it with a Flexi-Coil 5000 air-drill and 3450 air-tank. He seeds on 12 inch row spacing and his opener has a four inch spread tip. His seed-placed fertilizer rate was a blend of 30lb N, 30lb P, 5lb K and 10lb S. Another 10lb/ac of liquid N was applied as the carrier for the first application of Roundup, and 35 pounds of N was top dressed in mid-July. A second Roundup application was used to clean up later flushes of weeds. "We had so much rain and the corn canopy was slow to fill in, so we used a second application to keep the weed competition down," explains Thiel. Research showing air-drills work At St. Brieux, Jason Kirsch with Bourgault Industries says that a research program is comparing row planters to an air-drill. The 2003 results looked promising but the 2004 results were inconclusive due to weather-related problems. In the trials, conducted by PAMI, grazing corn was grown at St. Brieux and Portage La Prairie. At St. Brieux in 2003, solid seeded (air-drill) grazing corn DKC27-12 was compared to barley silage. Corn was seeded with a Bourgault 5725 air coulter drill and 5440 air-seeder. Corn was planted at 30,000 seeds per acre. At Portage in 2003, solid seeded DKC27-12 hybrid corn was sown at 29,000 seeds per acre, while a John Deere 7000 row planter on 30 inch spacing seeded 28,000 seeds per acre. "In the 2003 trials, the Bourgault solid seeded corn showed a 17 percent yield advantage over the row planter plot at the Portage site. It is just one year of results, but it indicated good potential for solid seeding corn," explains Kirsch. Calibrating the seeding rate Each bag of Dekalb corn contains 80,000 seeds, and the weight is printed on the bag since the weight varies slightly from bag to bag. To start the calibration, choose the desired seeding rate, say 30,000 seeds per acre, and divide by the number of seeds per bag. In this case, that gives you 0.375 bags per acre that will be used. Then, multiply the bag weight by the number of bags per acre to get the seeding rate in pounds per acre. For example, if the bag weighs 42 pounds, then your seeding rate is 15.75lb/ac (0.375 bags per acre x 42lb per bag = 15.75lb/ac). Ripley says that since there is some variation in the bag weight, simply take an average weight when making the calculation. "Make sure you order all the same seed size, as corn comes in different sizes. As well, there can be up to 10 pounds difference between bags, so make sure to use an average weight for each field." From there, the pounds per acre seeding rate can be used to set up the air-drill. How that is accomplished depends on the make and model of equipment. For example, with the Flexi-Coil system, one of two different seed metering rollers can be used to seed corn. Darryl Priel, CNH crop production specialist at Saskatoon representing CaseIH, New Holland and Flexi-Coil, says that the fine-segmented roller is recommended for seeding corn. "Segmented meter sections are available at a low cost, reducing the change-over investment for the producer who desires improved in-row spacing than what the coarse roller provides," says Priel. It can handle most corn grades with the exception of large, flat kernels. The segmented roller provides improved in-row spacing (spacing between the seeds in the row) than the larger fluted rollers in lower application rates. "The coarse meter roller, which is recommended for crops like peas or beans, works better for large, flat seeds, however, in-row spacing may be sacrificed," explains Priel. On New Holland, Case IH and Flexi-Coil air-carts, setting the seeding rate is then simply done with the monitor system, as is done with other crops. The smart monitor/controller provides meter drive settings for mechanical meter drive systems based on desired application rate, calibration volume and width of implement. There are no rate charts required. The variable rate meter drive system is easier, enter the desired rate in the monitor/controller, calibrate and go. Refer to the owner's manual for complete instructions. Kirsch says the Bourgault air-tank uses a metering auger to measure out the seed. One tank has a double flight auger for seeding lower rates of seed, from two pounds up to 150 pounds per acre. The second tank has a single flight auger that can seed up to 250 pounds of product per acre. "Corn is usually metered out through the double auger tank and it works just as well as with any other product. To seed corn with a Bourgault air-seeder, the operator performs the typical power calibration procedure to achieve the target seed rate," says Kirsch. Ripley says that getting the targetted plant population goes a long way to maximizing tonnage and feed value. He says that seeding at 30,000 seeds per acre helps to ensure that the seeds are spaced evenly to allow each plant to develop with minimal competition from neighbouring plants. Yes, the seeds will be somewhat randomly spaced, but on average, the stand is fairly uniform. "Over the last four years, we've seen good successes with air-drills and air-seeders. As long as growers can achieve the targetted plant population with fairly uniform plant spacing, they should be okay with an air system. Those factors are much more important than row spacing," says Ripley. -30- |
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