Farm Horizons, Oct. 2015
Early planting dates = high grain yields
By Dave Schwartz
The 2015 growing season was a reminder that early planting dates are key to high grain yields.
Minnesota is in the northern corn belt, so getting the crop planted on time is a key to high grain yields.
Crops in south central Minnesota need all the growning degree units (GDU) that are available during the growing season.
A corn crop planted April 15 has a huge advantage over the same field planted June 1.
Soybeans planted early in the season have more vegetative growth, and, most likely, more nodes, so this is an advantage for them, too.
I’m expecting corn and soybeans planted by May 7 to have a significant yield advantage over fields planted after this date.
Early planted fields had very little soil compaction. This is quite evident in the height of soybean fields planted before and after this date (8- to 10-inch advantage).
After May 6, rainfall for the remainder of the month in Litchfield totaled 6.7 inches, plus an additional 2 inches June 4. Over that 30-day period, we had 8.7 inches of rainfall. Many of the corn and soybean fields planted later in May and early June suffered from soil compaction.
Crops thrive with 80-degree temperatures and timely rainfall. The high temperature in Litchfield for the months of July and August was 88 degrees. We did not reach 90 degrees until Sept. 5. By this time, corn had pollinated, set seed, and kernels had dented.
The lack of moisture stress and heat stress is evident this year, as many ears are filled to the tip and kernel depth is deeper than normal.
The combination of early planting date, lack of 90-degree temperatures, and timely rainfall should lead to one of our best crops on record.
Another sign that this was a good growing season is that lawns stayed green the entire summer.
Broadleaf weed pressure continues to grow. Giant ragweed and waterhemp plants were visible in most soybean fields this fall. This was due, in part, because we had regular rainfall this summer, which triggered more weed flushes.
Also, early planting dates put additional pressure on herbicides to perform. Working fields in April has little effect on weed populations when most weed seeds don’t germinate until May. Even though residual herbicides at planting may have provided 95 percent weed control, this was not enough.
Walking fields this summer, I noticed low ground that drowned out in 2013, and grew up into weeds in 2014. Without crop competition, these areas were great seed production areas for giant ragweed and waterhemp.
If Dicamba-resistant soybeans are approved for the 2016 growing season, this trait should provide growers an option for controlling these two pesky weeds in soybeans.
With the high yield environment we had this growing season, I am expecting solid seeded soybeans to excel, as well as higher corn plant populations.
Have a safe harvest.