Last week, How to capture 100-bushel soybean yields offered a few clues on boosting soybean yields from Charles Farms’ 107-bushel contest entry in Pennsylvania’s 2017 soybean yield contest. But you really need to dig deeper into common management practices employed by all soybean growers trying to push up yields using contest plot yields.
As Penn State senior Extension agent Del Voight pointed out, the 2017 average (mean) yield of all 35 state contest entries was 80.85 bushels per acre, up more than 4 bushels from 2016. That’s a sizable jump for any average, compared to the long-term annual average increase of 0.4 bushels.
Here are a few clues surfacing in the summary of the contest results available on the Pennsylvania Soybean Board website:
• Seed brands. Of the eight company brands entered, 17 were Pioneer numbers; seven were Hubner; four were Asgrow.
• Dominant varieties. Of the total 35 entries, 23 were in south-central Pennsylvania, which influences maturity group selection. The most common varieties were Pioneer numbers, with seven using 36T86 and four using 31T77.
• No-till ruled. Some 71% of entries used no-till and produced the highest yield average — 83.37 bushels per acre. Min-till came in next with a 76.17-bushel average. Conventionally-tilled entries averaged 68.08 bushels.
• Planting method. Some 63% of entries were planted with a corn/soybean planter and averaged 79.88 bushels per acre. The other 37% drilled their beans and averaged 82.49 bushels.
• Row widths. About 49% of entries were planted in 11- to 20-inch row widths, and averaged 83.06 bushels per acre. Beans drilled in 10-inch row widths or less averaged 79.76 bushels, while those planted in 30-inch rows averaged 77.77 bushels.
• Planting date effect. Earlier proved to be better than later in 2017. All except one regional winner had their entries planted between April 20 and May 4. Some 70% of entries planted May 10 or earlier averaged 82.14 bushels per acre. About 24% of entries planted between May 11-20 averaged 79.24 bushels. Those planted after May 30 averaged 64.76 bushels.
• Plant protectants. Some 49% of entries treated with a combination of foliar fungicides and insecticides averaged 83.01 bushels per acre. The 9% treated with only a foliar insecticide averaged 87.65 bushels. The 11% treated with a foliar fungicide averaged 78.65 bushels, while the 31% receiving neither treatment averaged 76.45 bushels.
• Seed treatment. About 91% of entries used a seed treatment, producing an 80.31 bushel average. The 9% not employing a seed treatment averaged 83.25 bushels.
• Rhizobia inoculation. The 89% of entries treated with an inoculant averaged 81.45 bushels per acre, while those not inoculated averaged 76.43 bushels. Those treated with liquid inoculant averaged 85.78 bushels, while the dry inoculant averaged 76.28 bushels.
Beyond that, there were small, less significant differences in how management practices affected yields. For instance, 66% of entries using no foliar fertilizer averaged 81.57 bushels, while those using foliar-applied fertilizer averaged 80.46 bushels.
Average seed drop was 163,813 per acre — continuing a steady decline over the years. Average plants at harvest were 121,616 per acre — a 35% loss from planting population, also continuing a gradual harvest population decline.