While this article was published by The Ohio State, it is good information for every corn farmer

Diagnosing Emergence Problems in Corn - Peter Thomison, Pierce Paul, Ron Hammond

In some Ohio counties, corn planting is nearly complete and corn is emerging, whereas in others, little or no corn has been planted due to persistent rain and cool soil conditions.

Diagnosing emergence problems early is critical in identifying solutions and developing successful replant plans, if needed. Here's a list of a few common things to look for if you encounter an emergence problem in corn this spring.
(some of this information has been adapted from a newsletter article by Dr. Greg Roth, my counterpart at Penn State).

- No seed present. May be due to planter malfunction or bird or rodent damage. The latter often will leave some evidence such as digging or seed or plant parts on the ground.

- Coleoptile (shoot) unfurled, leafing-out underground. Could be due to premature exposure to light in cloddy soil, planting too deep, compaction or soil crusting, extended exposure to acetanilide herbicides under cool wet conditions, combinations of several of these factors, or may be due to extended cool wet conditions alone.

- Seed with poorly developed radicle (root) or coleoptile. Coleoptile tip brown or yellow. Could be seed rots or seed with low vigor. Although corn has just started to emerge or has not yet emerged, growers should carefully inspect seedlings for symptoms of disease. This is especially true in lower lying areas of fields where ponding and saturated soils were more likely. Seeds and seedlings that are brown in color, are soft and fall apart easily while digging are obviously dead or dying. Seeds and seedling roots or shoots that have a weft of white to pinkish mold growing on them are likely victims of fungal attack and will likely die. Pythium and Fusarium are common fungi that attack plants and cause these damping-off or seedling blight symptoms under wet, cool conditions. It is more difficult to diagnose disease damage on plants that also show abnormal growth caused by cold soil conditions or by crusting of the soil surface. However, dark, discolored roots and crowns, instead of a healthy creamish-white appearance, are typical symptoms of seedling diseases problems. So, it is best to check these seedlings very closely for dark brown or soft areas on seedling roots and shoots. Any discoloration will indicate a problem that could worsen if the soils remain cold or wet.

- Seed has swelled but not sprouted. Often poor seed-to-soil contact or shallow planting- seed swelled then dried out. Check seed furrow closure in no-till. Seed may also not be viable.

- Skips associated with discolored and malformed seedlings. May be herbicide damage. Note depth of planting and herbicides applied compared with injury symptoms such as twisted roots, club roots, or purple plants.

- Seeds hollowed out. Seed corn maggot or wireworm. Look for evidence of the pest to confirm.

- Uneven emergence. May be due to soil moisture and temperature variability within the seed zone. Poor seed to soil contact caused by cloddy soils. Soil crusting. Other conditions that result in uneven emergence already noted above, including feeding by various grub species.

Note patterns of poor emergence. At times they are associated with a particular row, spray width, hybrid, field or residue that may provide some additional clues to the cause. Often two or more stress factors interact to reduce emergence where the crop would have emerged well with just one present. Also, note the population and the variability of the seed spacing. This information will be valuable in the future.

Don’t forget that corn may take up to 3 to 4 weeks to emerge when soil conditions are not favorable (e.g. temperatures below 55 degrees F, inadequate soil moisture). This was widely observed in many fields in 2005 when corn planted in mid April did not emerge until the first or second week of May. As long as stands are not seriously reduced, delayed emergence usually does not have a major negative impact on yield. However, when delayed emergence is associated with uneven plant development, yield potential can be reduced.

Our customers for years have told us that they are growing better corn and beans than ever with our products. Was it the calcium or the sulfur, or something else? For years Iowa State has told us that Iowa soils have enough calcium and sulfur, well calcium anyway. In the newest research they have found corn does respond to applied sulfur, 82% of the time.

Summary from Evaluation of Corn Response to Sulfur Fertilization in Northeast Iowa, John Sawyer
Corn grain yield increase to S fertilization has occurred with high frequency in these studies. Also, the magnitude of yield increase has been large. Across the two years and three studies, 82% of the sites had a statistically significant yield increase to applied S fertilizer. By study, statistically significant across-site yield increases averaged 15, 18, and 38 bu/acre. Analyzed across S rate, the economic optimum S rate was 14 lb S/acre for fine-textured soils and 24 lb S/acre for coarse-textured soils. This research indicates a dramatic change in need for S fertilization in northeast Iowa, and that S application is an economically viable fertilization practice on many soils.

Read the whole article here.

In case you’ve never used sulfur products their price is rising along with other inputs. Many dealers have reported not being able to source enough sulfur. Fortunately since SuperCal SO4 is made in Iowa from a natural mined source, its price has not risen as dramatically as other sulfur products. In fact using SuperCal SO4 in bulk at the universities recommendations will cost you $7.50 to $10.50 per acre, quite a bit cheaper than other products on the market.

While we have been sold out for over a year we have just finished our plant expansion and should be able to meet demand for the coming years. As an added bonus, SuperCal SO4 doesn’t cause soil acidity like ammonium sulfate, thiosulfate, or elemental sulfur does. Though we do sell lime is you want to add more cost to your fertilizer bill!

We have received a number of phone calls recently on SuperCal SO4 and SuperCal 98G for tomatoes. SuperCal SO4 is the best product on the market to eleminate blossom-end rot. As always start with a proper soil analysis, then add fertilizers and ammendments as need.

Blossom end rot:

Blossom-end rot is a nonparasitic disease of tomato, pepper and watermelon. Losses can vary from a trace to more than 50%.

Symptoms

The first symptom is a slight water-soaked area on or near the blossom end of the fruit. The affected area soon darkens and enlarges in a constantly widening circle until the fruit begins to ripen. The tissues are dark and shrunken and have a dry, leathery appearance. With pepper the rot is tan in color and should not be confused with sunscald, which is white. The affected area may be merely a speck or it may involve half or more of the fruit. Secondary microorganisms may grow on the decayed area.

Cause

Blossom end rot is caused by a lack of calcium in the developing fruit. This may be due to a lack of calcium uptake from the soil or to extreme fluctuations in water supply. Incidence of blossom-end rot is also increased where there is a low ratio of calcium to certain other nutrients such as potassium and nitrogen.

Control

Although the most desirable calcium levels for preventing blossom-end rot have not been determined, the application of lime (SuperCal 98G) to fields known to be low in calcium has helped to prevent the disease. Soil should be limed according to recommendations of soil analysis report, usually to pH 6.5-6.8. The use of gypsum (SuperCal SO4), at rates of 500 to 1000 pounds per acre (1 to 2 pounds per 100 square feet).

SuperCal 98G and SuperCal SO4 can be applied 2 weeks in advance of planting due to the fineness of the base material. Other lime and gypsum materials may need to be applied months in advance.

http://www.ces.ncsu.edu/depts/pp/notes/oldnotes/vg19.htm