Think Different: Luck or Genetics
Drought stricken soybeans that pushed yield records had several advantages:
- Perfectly timed August rains.
- Reproductive resilience. While corn has only one chance to develop an ear and tassel, soybeans can abort many flower flushes and still produce more. Soybeans can compensate if environmental conditions change.
- Normal August day and night temperatures.
- Deep roots; some reported at 5, 6, 7 and even 9-ft. depths to find moist soil.
- Drought suppressed pests and disease.
Lenssen advised soybean growers who asked if their crop was dying to check soil moisture. He reports that some pulled backhoes into fields and found that soybean roots reached 5, 6, 7 and even 9-ft. depths to find moist soil.
Like his counterparts to the East, Lenssen reports very little disease this past year, and without excess moisture, iron chlorosis was also not a problem. Sudden death syndrome, brown stem rot and Phytophthora were all largely absent, as were most insects.
"Most diseases need sustained, relatively high humidity, and we didn't have enough humidity or inoculum to have even moderate levels of foliar disease," notes Lenssen. "We had some Japanese beetles early, and two spotted spider mites were more frequently seen than in most years, as they respond to really dry and dusty conditions. Even where growers had possible yield reduction early in the season, when the weather turned cooler and wetter, the plants compensated with new growth, leaves and racemes, and flower clusters."
Even though some areas were dry in 2012, a moisture-rich soil profile from previous years helped North Dakota soybeans do well this year, according to Hans Kandel, North Dakota Extension agronomist. "Even the worst areas in North Dakota got some rainfall, but there were regions that were definitely way below annual precipitation levels," he says. "As the season unfolded, root systems were able to tap into that stored soil moisture. A lot of the production came from soil moisture. We are monitoring the water table, and it dropped below our 6-ft.-deep observation wells. That hasn't happened in the past six years or more."
The drier conditions did produce a drier canopy than normal, notes Kandel. As a result, North Dakota soybean growers saw very limited disease. "We often battle Phytophthora root rot, but it was definitely less this year," he says. "Other diseases were also at a minimum, and we ended up with a fairly healthy crop."
Better than average yields for North Dakota were in the 30s, though North Dakota varietal trials produced yields in the 50, 60 and even 70 bu./acre range in dryland conditions and as high as 85 bu./acre in irrigated plots.
"Growers and myself were surprised with the yields," says Kandel. "Though we didn't have rain in that critical period, we ended up with a very good crop. The warmer than normal year also contributed to yields, as most of our beans were mature before frost, with even the longer maturities filled out completely."