Corn- The soil temperatures at the 2-4 inch depth is averaging 70-75°F. Soil temperatures at the 8 inch depth are almost 70°F with soil temperature in the 2-3 foot range averaging in the mid 50’s. Corn that was planted April 15-25 has 425 Growing Degree Units (GDU’s) with corn planted May 5 averaging 400 GDU’s and corn planted May 15 having 290 GDU’s.
Corn plant development is from germination to V4 (4th visible collar on the corn plant.) Corn plants that are at V4 are on average 7-8 inches tall with some plants exhibiting sulfur deficiency showing lighter shades of green/yellow and striping of plants.
Photo Courtesy of University of Illinois Extension
Sulfur deficiency symptoms are not uncommon in cooler/cloudy years or areas of the field that have higher levels of residue in them. We also see these symptoms when corn is growing very rapidly from V2 to V5. In most cases these symptoms go away once the soil temperatures start to rise and we have more mineralization of sulfur from the soil, however this deficiency may have affected yield. (More information on sulfur deficiency can be found at www.centralvalleycoop.com under the Agronomy tab, topic of the week April 27.)
We are seeing areas of fields with crusting and compaction, that even our slow gentle rains in May did not help the corn come through, in which replanting may be necessary. We are seeing this stand loss issue in all planting dates with the issue being soil conditions in those areas and not the planting date. In quoting Bob Schoper “the problems / sins you commit in the spring with tilling or planting when it is just a shade to wet, will follow you all year.” In most instances the end rows and low areas are the hardest hit with some spring applied manure fields looking about the same.
Tissue Testing-As plants hit the V5-V6 growth stage the growing point starts to come out of the ground and the root system is growing down and out into the row. The plant at V5-V6 is at a critical stage and is deciding the number of rows around the ear will be. Having a tissue test prior V5-V6, will help you in planning your in-season plant nutrient needs and application.
Soybean plant development is from germination to V1 (first trifoliate leaf unfurled).
Photos Courtesy of Iowa State University Extension
The picture on the left shows a soybean plant after VE (emergence) stage and then at VC (cotyledon) stage. The picture on the right shows the soybean plant at V1 (first trifoliate unfurled).
In the last 10 days there has been much discussion regarding rolling soybeans with the wet ground we have had this spring. The negatives of rolling soybeans in wet ground is that you may increase soil crusting and the potential of seed and seedling diseases, which may decrease yield and make for poorer standing beans next fall. If you want to roll your soybeans and the ground is still wet prior to soybeans emerging wait until after V1 and roll the soybeans in the heat of the day. By rolling in the heat of the day the soybeans plant is dry and is less likely to stick to the ground and pick up any more diseases.
Central Valley Website-If you have a chance check out the updated Central Valley website at www.centralvalleycoop.com we have previous Agronomy Notes articles as well as topics of the week under the Agronomy tab. We also have updates on markets and weather on the website.
Answer Plot -Our next Answer Plot session in Hayfield is Monday, June 13, with a 8:30 AM registration and a 9:00 AM start. We will have Bob Schoper and other agronomists lead us through this session. Other Answer Plot Dates are:
- Friday, July 15 8:30 AM
- Thursday, August 18 Time To Be Determined
Monsanto School Grant- Monsanto is allowing schools to apply for a $25,000 grant. One of the criteria used to award the grant is the amount of farmer support for the schools. The more nominations for a particular school district, the better their chances of getting the grant. Listed below is the link for this nomination process. http://www.monsanto.com/americasfarmers/Pages/grow-rural-education.aspx We do have hard copies of this information at your local Central Valley Coop Agronomy location.
