The week of April 25 was windy enough so that a few farmers commented that they were wondering if it was an election year. This wind did help dry out the soil enough that there was some planters rolling in the field mid to late week.
The week of April 26 to May 2 did have some wind with speeds of 5-20 MPH compared with the previous week of 15-30 MPH. This wind coupled with warm sunny days helped dry the soil so that farmers were planting in some of the best field conditions that have experienced in a few years.
Soil temperatures fluctuated from 34°F- 76°F at the 2” depth and 37°F- 66°F at the 4” depth, with soil temperatures at the 8” depth ranging 43°F -60°F.
| Depth | Soil Temperature | Average |
| 2″ | 34°F-76°F | 55°F |
| 4″ | 37°F-66°F | 51.5°F |
| 8″ | 39°F-60°F | 49.5°F |
Soil temperatures at the 20” depth were in the 40°F-50°F range, and at the 40” depth stayed in the 40°F’s.
Corn plant development is from germination for recently planted seed and emergence on corn that was planted mid-April.
| Planting Date | GDU’S | Plant Stage | Growth Stage | Plant Height |
| 15-Apr | 112.5 | Coleoptile Emergence Soil | VE | .0-1″ |
| 23-Apr | 64.5 | Seminal Root Emergence | ||
| 30-Apr | 30.5 | Radicle Root Emergence |
We picked up 8.5 Growing Degree Units (GDU’s) for the week of April 25th which is 23.5 GDU’s less than the 30 year average of 32 GDU’s during that time frame. During the week of May 2nd we accumulated 60 GDU’s which is 16 GDU’s more than the 30 year average of 44 GDU’s during that time frame.
In comparing GDU’s for the April 15-30th time frame we accumulated 90.5 GDU’s in 2015 compared to 78 GDU’s for the 30 year average. The table below breaks the GDU information down to daily accumulations versus the 30 year average.
| Dates | 2015 GDU/Day | 30 Year GDU Average/Day | Difference/Day |
| April 19-25 | 1.21 | 4.57 | -3.36 |
| April 26 to May 2 | 8.57 | 6.29 | 2.28 |
| April 15-April 30 | 5.66 | 4.88 | 0.78 |
The seed pictured below and on the left is a seed that has germinated and has the radicle root just emerging from the seed. With the seed pictured below and on the right showing the radical root elongating and the Coleoptile just starting to emerge from the seed and start its journey towards the soil. The radical root will always grow down, this process is called Gravitropism or the plant roots response to gravity.
The seed pictured below and on the left shows the coleoptile stretching towards the soil surface while the radical root has put almost 2” of growth on. If you look closely you can see that the plant has put on its seminal roots and that they are growing out. The seminal roots normal emerge from the seed between 60-70 GDU’s. The seminal roots will continue to grow until emergence (VE) but will slow down and stop at about the 3rd leaf (V3). The seminal roots as well as the radical root are the first to access any starter or “pop up” fertilizer.
The seed pictured below and on the right is just emerging from the soil and is at the early stages of VE. At VE the coleoptile will cease to elongate and the foliage that follows will be the embryonic leaves. Shortly after the coleoptile emerges from the soil surface the nodal root system will start to grow and will become the major supplier of water and nutrients to the plant by the V6 stage.
The table below shows the approximate range of GDU’s at which stage of plant growth and development takes place.
| Plant / Leaf Stage | Growth Stage | GDU’s |
| Germination | 10 to 20 | |
| Radicle Root Emergence | 30 to 40 | |
| Coleoptile Emergence Seed | 50 to 60 | |
| Seminal Root Emergence | 60 to 70 | |
| Coleoptile Emergence Soil | VE | 100 to 150 |
| First collar on emerged leaf | V1 | 150 to 190 |
| Collar on second Leaf | V2 | 190 to 220 |
| Collar on third leaf | V3 | 280 to 310 |
| Collar on fourth leaf | V4 | 370 to 400 |
| Collar on fifth leaf | V5 | 450 to 470 |
| Collar on Sixth leaf | V6 | 530 to 550 |
| Collar on Seventh leaf | V7 | 600 to 620 |
Soybean plant development is from still in the bag or planter to germination. The picture below shows various stages of germination of a soybean plant and the elongation of the primary or radical root.
For soybean germination to take place the soybean seed must first absorb 50% of its weight in water, shortly after that the primary or radical root will emerge and Gravitropism takes over and that root will start to grow down. Shortly after the radical has emerged and started to grow down, the hypocotyl (which is the small section of the stem between the cotyledon or seed leaves and the radical) begins to stretch out and grow toward the soil surface pulling the cotyledons or seed leaves towards the soil surface
Planting Progress- Corn planting progress was at the 85-90% range by Saturday May 2 with Soybean planting progress between 40-50% complete.
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