Soybean harvest in southern Minnesota and northern Iowa is in full swing as October approaches.That being said, a review of some harvesting tips may be in order.
Remember that any North Country Seed production contracts that involve identity-preserved (IP) soybean require that the grain of the IP varieties be kept separate from all other varieties.For 2009, North Country Seed/Galena Genetics offered premium contracts on two IP varieties, 19G01 and 19G02.Please recall that these two varieties must also be kept separate from each other.This is a very important requirement due to the unique physical and chemical properties contained in the seed of these two varieties.
Thorough combine clean-out when switching from one variety to another is important, when harvesting IP varieties.This can be time consuming but essential to preserving the purity of IP varieties, or preventing the contamination of non-GMO varieties with genetically modified traits.Lack of IP variety purity and GMO contamination can cause loads to be rejected at the elevator warehouse.
Harvest order will help avoid contamination problems.If possible, harvest your IP varieties first, followed by your non-GMO varieties, followed by your RR or other GMO varieties.If corn was the last crop to be harvested with the combine a year ago, the corn harvest will have easily flushed out any GMO soybeans lying around in the combine.
If you MUST harvest a commodity or RR soybean variety prior to harvesting an IP variety, run the combine empty, “shake it down”, to remove as much seed as possible of the prior commodity or RR variety.Then “flush” the combine by running 15 – 20 bushel of the IP variety through the combine.Dump this seed with the commodity or RR variety, and again “shake down” your combine empty before harvesting the bulk of your IP variety.
Although I mentioned it last month, it is worth repeating, proper combine settings can do much to improve the quality of the soybean seed coming off the combine.A few unthreshed pods are more easily removed from a load of soybeans than are split and damaged seeds.As the temperature and other weather conditions change during the course of the day, the moisture of the soybean seed will change, and consequently the susceptibility to seed coat fracture and splitting.Monitor the threshed seed periodically, and make adjustments if necessary.
Soybean Lodging
So far this fall, soybean lodging does not seem to be a major problem in southern Minnesota and northern Iowa. (Knock on wood.)In situations where lodging has occurred, several harvesting tips may help to get more soybeans into the grain tank.These tips include slower ground speed, adequately sharpened and aligned cutter blades, and, in extreme lodging conditions, cutting in one direction.
Varietal selection is important to reduce soybean lodging in the field.Any soybean variety can lodge under extreme conditions.These conditions usually include environmental factors that promote luxuriant vegetative growth during the summer – especially at the beginning of seed fill in August.Severe wind and/or rainfall can cause the entire canopy to collapse under its own weight.When the canopy is down for an extended period of time, the plants may lose their ability to return to an upright position, even after leave senescence.Galena Genetics places high priority on lodging resistance in our breeding and development program.
Corn development and stalk rot
The corn crop finally appears to be finishing grain fill in most fields, but not without some premature death due to stalk rot.During September, many corn fields were showing a significant number of dead and prematurely dying plants that had not yet finished filling grain on the ear.These dead plants often occurred in small clusters which tended to increase in size as the season progressed.In most cases, premature death of these corn plants was caused by stalk rotting fungi which entered the plant through the root and proliferated in the nodal tissues of the root crown and stalk.The rotting organisms would, in effect, strangle the plant, cutting off necessary water and nutrients from the roots, causing the plant to die before grain filling was completed.There are several fungal species which cause stalk rot to occur.The primary types this year appear to be Fusarium and Anthracnose, although in most cases, several other fungi can likely be found to have joined in the “party”.
Stalk rotting fungi might be compared to vultures or hyenas that attack their prey when it is already in serious trouble.Corn stalk rot occurs when the corn plant is already under some other type of stress which prevents adequate supplies of energy (starch produced from photosynthesis) from being available to the corn plant during the grain-filling period.This stress can occur in many different ways, e.g. – drought stress, heat stress, cold stress, nutrient stress, foliar disease stress, insect stress, etc.Couple any of those stresses with the fact that grain development in the ear is demanding large amounts of energy (starch) simply creates a situation in which the corn plant is in a weakened state.In this weakened condition, the corn plant may not be able to adequately prevent the proliferation of stalk rotting fungi.
This year’s cooler-than-normal temperatures throughout the summer were conducive to early development of Fusarium stalk rot.Early development of Fusarium stalk rot will lead to softening and rotting of the root crown and stalk, especially the lower stalk.Damage and losses from Fusarium stalk rot may occur in two ways.First, if the plant dies prematurely, nutrients and energy can no longer be transferred to the developing ear, thus causing the ear to die before grain is filled completely, resulting in less grain yield and lower test weight.Secondly, the soft, weakened stalk and root may not support the weight of the ear, causing stalk and root lodging to occur, especially if severe wind and/or rainfall occur late in the season prior to harvest.Stalk and root lodging, of course, create harvest losses and make the harvest process more difficult.
Anthracnose stalk rot is also prevalent in many corn fields this fall.The most obvious symptom of anthracnose stalk rot is the premature yellowing and dying back of the top of the corn plant before the rest of the plant is mature.Anthracnose stalk rot may not cause as much harvest loss since stalk breakage is nearly always restricted to the portion of the stalk above the ear.However, physiologically, anthracnose can also cause yield losses due to reduced grain development and lower test weight.
The degree to which stalk rots in general have affected corn yield and standability this year depend on how soon the corn plants came under serious stress and how well the specific hybrids were able to handle that stress.I have certainly seen years in which the problem was much more severe than it is this year.The high winds we experienced over the last couples days have certainly caused some corn to lodge, below the ear as well as above the ear.Undoubtedly this will make corn harvest more difficult in some cases.I do also expect to see some lower test weights as a result of stalk rot.Just how low test weight will go will depend on how early the plants died and what percentage of the field was affected by the stalk rot.
Seed bed preparation
Say what?Who the heck is worrying about seed beds at harvest time?The fact is, preparation for next year’s planting begins as soon as this year’s crop is harvested from the field.In fact in the ideal world, maintaining optimum soil conditions for planting is a year-long job.Obviously soil testing and fertility are important factors to consider.Just as important is soil aeration and tilth.If soil compaction or hard-pan is a problem, fall subsoil tillage can be an excellent method of opening up the soil prior to winter freeze.This will allow better water and air movement through the soil profile, and ultimately allow better extraction and water and nutrients from the soil by next year’s crop.
Another useful practice for soybean seed bed preparation is stalk chopping or stalk shredding.This practice will break up larger corn residue and root balls.This practice can be especially useful in minimum-till or no-till operations as it helps create a more uniform seed bed, which allows more uniform planting depth and better seed-soil contact.
End of the growing season
As the growing season is coming to a close, so will my monthly notes be coming to a close for a short time.I have truly enjoyed writing these notes.I hope that you have found them to be interesting, informative, and educational.I always enjoy the feed back I get from you, so do not hesitate to contact me if you have something on your mind.In the meantime, please have a safe and successful harvest season!
