All three fields were planted with the same variety by the same planter, by the same person. The soil types are somewhat different, but the fields were planted within a day of each other, all during the last week of April. The difference was in how these three fields were prepared for soybeans.
Field A was no-tilled into standing stalks with the Kinze 8-row, split-tow planter. All the parts that contact soil were replaced before the season began. There was no tillage done in this field in either the fall or spring.
A Landoll vertical tillage tool was run across Field B last fall. It was also corn stalks. No tillage was done this spring before planting, making it a stale seedbed situation. The soils are slightly more rolling than in Field A.
Field C was in stalks and not worked last fall, but was hit twice with the Landoll vertical tillage tool with rolling basket before planting. The last trip before planting was only a few hours in advance. As for residue cover, the no-till field had the most, with the stale seedbed still showing lots of cover, and the field hit twice in the spring showing the least cover, but still more than a conventionally tilled field.
Here are stand count results. A hula-hoop with 26-inch inside diameter was thrown at random seven times in each field. The highest and lowest numbers were discarded, and the other five counts of plants inside the hoop were averaged to get a count for that field. Sometimes the hoop fell on only one of the 15-inch rows. A larger hoop might have resulted in a more accurate count. However, the same hoop was used in all three fields, and the results within each field were relatively consistent.
In Field A, the no-till field, the average count inside the hoop was 13.4 plants. If the stem was inside the hoop, the plant was counted. For the most part, plants within each field were uniform in size. A visual inspection would tend toward saying the plants were slightly taller in field c, and least uniform in height in field B, but no measurements were taken to document that observation.
Using the formula in the Purdue University Corn & Soybean Field Guide, the factor to multiply by the stand count for a 26 inch inside diameter hoop is 11,710. So the average stand count for Field A, no-till, is 156,914. The intended planting rate was 165,000, although according to the monitor it varied from 160,000 to 180,000 depending upon how much seed was in the boxes. Assuming 165,000, the farmer achieved 95% final stand in no-till. The old Purdue standby in conventional tillage was 90% germination, 90% emergence, which would have predicted 133,650 plants per acre. Obviously, seedling vigor and placement with the planter, even in no-till, is much improved.
The count in Field B, the stale seedbed, was nearly identical. The average count was 13.2 plants /hoop, or 154,572 plants.
In Field C, the field worked by vertical tillage twice in the spring, the count was about 1.6 plants per hoop higher, at 14.8. The average stand was 173,308. Obviously, the planter was seeding above the intended rate, and the germination and emergence was excellent.
All three results show excellent performance, and all three stands are far above what Shaun Casteel, Purdue University Extension specialist, is recommending. He says 120,000 plants per acre in 15-inch rows is enough.
We’ll report on yield this fall. However, it will be anecdotal, since these are whole fields of varying sizes and soil types, and not plot fields.