By Kent Thiesse
After delaying spring planting, rainy weather has slowed harvest progress in many areas of the Upper Midwest. Generally, soybean harvest has barely started in most areas of the Upper Midwest, and virtually no corn has been harvested other than for livestock feed.
Rainfall amounts during the month of September varied across Minnesota. The University of Minnesota Research and Outreach Center at Waseca recorded 6.69 inches of precipitation during September, more than double the normal precipitation amount for the month. The U of M research center at Lamberton received 6.02 inches of precipitation during September, nearly three inches above the long-term average for the month.
Portions of southern Minnesota had even higher amounts of total rainfall for the month, with several locations reporting 8-12 inches of rainfall. In addition, many areas of southern Minnesota have received 3-5 inches of rainfall during the first week of October.
Above normal temperatures during September in the Upper Midwest were quite welcome and allowed much the 2019 corn and soybean crop to either reach maturity, or be very close to maturity, by month’s end. Most of the corn hybrids that were planted in late April and the first half of May have reached physiological maturity; the rain, however, has limited field dry-down of the corn somewhat. Most soybeans are either at maturity or close to maturity, with full-scale soybean harvest ready to proceed once weather and field conditions are conducive.
Most of southern and western Minnesota, as well as surrounding areas of adjoining states, have not recorded the first 2019 freezing temperature of 32 degrees, as of October 7. As of September 30, the U of M research center at Waseca had recorded 2,456 growing degree units since May 1, nearly normal for the end of September.
The GDU accumulation for most of the 2019 growing season, prior to September, was 5-7 percent below normal. The higher than normal GDU accumulation in September greatly enhanced the maturity process for the 2019 corn and soybean crop, even on later planted crops in the region.
The early yield reports from the soybean harvest across the region, which are quite limited, have been fairly mixed. There have been some yield monitor, weigh-wagon, and test plot soybean yields of 60 bushels per acre or higher reported in southern Minnesota. Of course, it should be pointed out that “whole field” yields are determined by dividing total bushels harvested by the total acres in a field that were planted last Spring. When using this yield calculation, whole field yields of 50-60 bushels per acre have been more common, with lower yields in areas that were hardest hit by excessive moisture earlier in the 2019 growing season.
There are many farms with significant drowned out areas or partially unharvestable fields. These need to be factored into the final whole field yield calculations, significantly lowering those numbers in some cases. For example, a soybean field with a weigh wagon yield of 60 bushels per acre, measured in an area with no drown-out damage, would see the whole field yield reduced to 48 bushels per acre, if 20 percent of the field is not harvestable. There will be numerous soybean fields across the region that will have 10-20 percent or more of the total acres that are not harvestable this year.
Corn harvest has also been initiated in very limited areas of the region because of the corn in the field is still not dry enough to harvest. Ideally, corn needs to be dried down to about 15-16 percent moisture, either naturally in the field, or with supplemental drying, for safe storage in on-farm grain bins. The slow dry-down of the corn in the field in 2019 will likely result in significantly higher corn drying costs this year.
Stalk quality and strength have been a major concern as well, with significant stalk breakage and ear droppage already occurring in some fields. A high amount of “green snap” in some corn hybrids resulting from strong winds in July, together with corn diseases late in the growing season, is leading to weakening of corn stalks in some areas of southern Minnesota. Consistent standing water also is likely to result in weaker stalks, as well as more development of stalk rots, which could result in additional corn lodging.
Fall tillage and manure applications could also be challenging in many locations this fall, due the extremely saturated top-soil conditions. This type of soil situation makes it difficult for quality tillage and may require leaving portions of fields without fall tillage or manure applications. Producers are also reminded that soil temperatures should be 50 degrees Fahrenheit or lower for fall applications of nitrogen fertilizer for the 2020 crop year, in order to avoid significant losses. Soil temperatures at Waseca were still above 60 degrees in early October.
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