Weather playing usual role in planting
We have seen such a switch from last spring where we were waiting for the rain to subside so we could get the crops in the ground. Now, one year later, we are waiting for the rain to come! This week-end looks to be a scorcher and the National Weather Service is calling for temperatures to average 3 to 5 degrees above normal the next two weeks taking us into early June. Normal temperatures are highs in the mid to upper 70s and lows in the 50s. They are calling for lots of 80s for highs with a few days of 90s and 70s over the next two weeks.
The outlook is for a warmer and drier start to the summer — and scattered rainfall over the next few weeks could stress crops in June or July.
Uneven corn emergence: Some replanting has been taking place around the county, otherwise the crops seem to be standing fairly well. Some stands of corn seem to be highly variable and appear related to past cultural/weather events. In some fields we are seeing surface crusting and soil compaction.
What are some of the factors that may contribute to poor stands? According to Steve Prochaska, Extension Agronomy Field Specialist, the use of shallow tillage tools, work at soil depths of about 4 inches or less, following the year of record rainfall we had in 2011 and a mild winter without deep soil freezing and thawing may have further added to existing compaction. Also, some fields were compacted last fall during harvest. Finally, add heavy rainfall events in this spring and you have multiple factors that will contribute to loss of soil structure with concomitant soil compaction.
Prochaska also notes that other possible contributing factors to the corn stand loss in these fields include:
1. Rotation; limited rotations without wheat or forage and in some cases multiple year soybeans now followed by corn.
2. Organic matter (OM) of soils in some areas of the fields was less than 2 percent with a corresponding low CEC. Low OM soils may be more prone to crusting and compaction.
3. Use of pop-up fertilizer applied on corn seed at planting. Applying fertilizer to the seed is not a recommended practice. However, if it is done, for soils with CEC greater than 7, maximum salt index is 8 (lbs of N +K2 0).
4. Herbicide injury. For example, products containing cell growth inhibitors may under certain environmental conditions injure corn seedlings.
5. Insect injury. Various insects such as wireworms, seed corn maggots, grubs, etc. have the ability to reduce plant stands.
6. Corn seedling diseases caused by various pathogens.
7. Malfunctioning corn planter over seedling depth, fertilizer delivery, etc.
The above factors may have been exacerbated by very early planting (first week of April). Corn was slow to emerge (in some cases three weeks or more) and was exposed to wet/dry/cold weather events. For more information, visit etension.entm.purdue.edu/pestcrop/2012index.html.
Rob Leeds is an OSU Extension Educator in Delaware County.