|
Optimizing soybean yields not unrealistic"By scouting each field weekly and taking notes, management decisions can be made to get to the yield potential of your crop," said Palle Pederson Iowa State University Extension agronomist. By Jennifer Bremer Farmers are all wanting to know how to get the record yields like a Missouri grower had last year, but not everyone has the resources to raise 139 bushels per acre, so knowing your own land is the start of optimizing yields. Iowa State University Extension agronomist, Palle Pederson said that so many soybean producers are not meeting the yield expectations that they could and should be getting. "Soybean yields are increasing slowly, but the numbers are not matching that of corn," said Pederson. "Therefore, it is important to know what management practices need to be done to increase these yields." He said that there are many factors to take into consideration when optimizing soybean yields, but they are not unrealistic.  SOYBEAN EXPERT—Iowa State University Extension Agronomist Palle Pederson explained ways to optimize soybean yields to a group of producers and industry specialists at a meeting in Nevada, Iowa on Feb 22. (Journal photo by Jennifer Bremer.) Variety selection First is variety selection. Pederson said that selecting the right variety to match the land is important. USDA data shows that since 1976, soybean yields have steadily increased an average of .5 bushels per acre compared to the 1.6 bushels per acre for corn. Much of the proper variety selection should include minimizing the impact of soybean cyst nematodes (SCN). In many of the Cornbelt areas, he suggested planting SCN-resistant varieties on fields that are infested with SCN. Currently, only about 45 percent of the soybean varieties sold in Iowa are SCN-resistant. "We need to increase the use of SCN-resistant varieties to decrease the loss seen in Iowa fields," he said. "It is estimated that SCN cost Iowa farmers 50 million bushels in losses in 2004." Pederson said that soybean cyst nematode infests more than 75 percent of Iowa soybean fields and can clip yields by more than 50 percent. Currently there are many SCN-resistant high-yielding varieties available. He said that farmers have been reluctant to use these varieties because yield drag existed in the early 1990s, but that no longer is the case. In 1991 less than 50 SCN-resistant varieties were available and now there are several hundred available and they have the same yields as those without SCN protection, while protecting against the potential loss from the disease. Finding just one SCN in a field is enough to consider the disease a problem. He said that if proper management practices are in place then the problem can be dealt with. "It's important to build up resistance early on. If you find cysts on roots in early July, you are already losing yield at that point," he added. "Yields will be more consistent if SCN-resistant varieties are used." Pederson said that SCN management goals should be to improve soybean canopy which leads to better yields, to reduce SCN infestation and to preserve yield potential of SCN-resistant varieties. "The problem is that no variety can do all three, so finding what can help in one or two of the three areas can help improve yields," he said. Plant growth and development Soybean growth and development are important for improving yields also. Bumping up planting time can lead to better yields also. Pederson said to ignore the soil temperatures and rather look at the calendar date, weather forecast and seedbed conditions. "If seedbed conditions are good, you can plant as early as April 25 in the bottom two-thirds of Iowa and May 1 in northern Iowa," he said. "In 24 experiments across Iowa since 2003, 79 percent of theSoybeansthat are planted early will yield greater than waiting until later in May." He also recommended planting the highest yielding fields first because in low yielding environments not much change is seen. Pederson said that whenSoybeansget a head start they acquired early canopy formation and sometimes have early flowering. Having a full canopy during flowering and seed formation helps plants use sunlight to the fullest extent, thus boosting photosynthesis and increasing yields. Row spacing Row spacing can help improve growth and development too. Most Iowa farmers are planting 30-inch rows, but he said that 15-inch rows can increase yield potential. In high yielding fields, narrow row spacing can increase yields. However, when there is a lot of stress on the soybean plant and the yield potential is low, narrow rows do not always provide the same kind of yield advantage. Iowa State University's 2005 research showed an average of 4.6 bushels per acre advantage of 15-inch rows over 30-inch row spacing. Concerns that may arise with narrower rows are disease pressure and weed control. "Diseases are probably the most important thing to consider since there are so many post emergent herbicide options available for weed control today," said Pederson. White mold is the largest concern for growers since the fungus can spread quickly and is difficult to remove and lessen the impact on the plants. Harvesting narrower rows is easier and more efficient than harvesting wider rows. combine technology has increased efficiency and eased the distribution of plants through the combine. Pederson said it is important for producers to realize that there is no magic bullet when raising soybeans. "There are so many factors involved in growing soybeans. Be sure to manage what you can and what is needed. Basic practices are needed in the beginning, identify your yield limiting variables and make decisions based on that," he concluded. "By scouting each field weekly and taking notes, management decisions can be made to get to the yield potential of your crop." Jennifer Bremer can be reached by phone at 641-938-2342 or by e-mail at jbremermaj@hotmail.com. A 1 3/26/07 None Date: 3/22/07
Copyright/Privacy
Copyright 1995-2008. High Plains Publishers, Inc. All rights reserved. Any republishing of these pages, including electronic reproduction of the editorial archives or classified advertising, is strictly prohibited. If you have questions or comments you can reach us at High Plains Journal 1500 E. Wyatt Earp Blvd., P.O. Box 760, Dodge City, KS 67801 or call 1-800-452-7171. Email: webmaster@hpj.com |
| ||||||||||||||||||||
