Dave Eckhoff (DSM – Region 2, Minnesota)
Recent walks with customers in their fields have truly opened my eyes about the 2012 harvest season that is quickly approaching. Several factors need to be considered when planning this harvest. We have had several environmental factors to deal with this year. There was excessive replants due to historic rainfall totals, hail and wind storms, excessive heat and last but not least drought stress. I will take a look at some of these and how they will affect the 2012 harvest.
Hail
If you had a field that encountered a hail storm that bruised the stalks this season it should be a high priority to be first on the harvest list. Bruising can not only weaken the stalk, but it can be an entry point to stalk rots. Stalk rots can greatly increase the chances of lodging. High wind, and in some cases sand blasting, can also be entry points for stalk rots. The common stalk rot diseases caused by fungi include Gibberella stalk rot, anthracnose, Fusarium stalk rot and Diplodia stalk rot. In hot dry seasons, charcoal stalk rot may be prevalent. Pythium stalk rot is usually rare but may occur if the weather is excessively wet during the summer months.
Excessive Heat
Not only does excessive heat promote drought stress but it also accelerated the growth rate of corn this year. Much like last year, we are going to be looking at drier than normal corn moistures. Last year when harvesting plots we noted head loss in excess of 6 to 8 bushels per acre. This was due mostly to sub 15% corn moistures. It also had a lot to do with head angle, speed and type. Many customers adjusted stripper plates, slowed their heads down and changed the angle of the head one at a time and the best outcome was a combination of all three. Slowing the head speed and increasing ground speed seemed to also help. This practice helps the shelling because the head runs full but may promote losing more full cobs. An easy measure in 30 inch rows would be one bushel lost per ¾ pound cob on the ground per 21 and ½ feet for an 8 row or 2 kernels on the ground per square foot. Head loss is generally greatly reduced when harvest moistures are above 18%. Harvesting early may be a wise management decision when you weigh the high price of corn against this year’s low price of propane and natural gas.
Drought Stress
This will go hand in hand with excessive heat but will be much more variable within the field. Draws may produce a full cob while lighter soils may have a tipped or very small ear.
This is where hydraulic adjustable deck plates will be very helpful. This should not be the only adjustment to be watching though. With variable ear sizes and yield within the field setting the separator and looking for kernels left on cobs in many locations of the field is going to be very important. Taking drought stressed areas early may also be wise. Plants that were stressed after pollination may have pulled nutrients directly out of the stalks to fill the ear leaving the stalk depleted and subject to stalk lodging. Each field and hybrid will vary greatly this year with the timing of planting versus heat and rainfall variability.
Hopefully proper combine preparation/adjustment, careful field selection and possible early harvest may help you harvest every bushel this fall!
Resources for more information
Corn head settings http://www.agweb.com/article/corn_head_tune-up/ http://deltafarmpress.com/agco-offers-harvest-tips-drought-stressed-corn
Hail damage http://www.extension.purdue.edu/extmedia/nch/nch-1.html
Drought stress effects http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1064&context=extensionhist&sei
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