With the wet, cool spring we've had in 2009, many are concerned about the effects of late planting. While there are averages we can look at, 2008 showed us what variability was all about. Mid-June planted corn and soybeans last year provided above trend-line yields in many cases, of course all bets were off if water continuously forced replants into July (and then some).

The tried and true data from the Illinois Agronomy Handbook shows corn planting optimum dates are from April 20 to May 4 (wishful thinking at this point). These dates give 99 to 100 percent of yield. Looking at later planting dates, May 9 gives 97% and May 14 gives 95%. We do start seeing a more aggressive drop-off after May 15 with a May 19 yield potential of 91% and May 29 of 81%. Of course, the next question is "of what?" Yield potentials have increased dramatically of the last several years. 90% yield with a potential of 150 bushel corn isn't going to excite too many people, but that same 90% potential of 250 to 300 bushel corn won't be too shabby.

Later planting does have some advantages. Remember this year the soil temperatures returned to the lower 40's in mid-April. Later planting should give us a more uniform stand with less seedling problems. Insecticide used will also be applied closer to rootworm hatch, unlike some years when very early planting put the insecticide out there two months in advance.

A recent article in the bulletin discussed more recent research on planting date and yield. Central Illinois really didn't see much difference between April 9 and May 9 in yield over the trial period. There was more of a penalty for late planting in Northern and Southern Illinois than Central. You can read the entire article at http://ipm.illinois.edu/bulletin/article.php?id=1079 .

Looking back on things, there just weren't many opportunities for early work. As for planting, it would have been really hard to justify putting $250 to $325 a bag seed corn out there in 42 degree soils. There is still plenty of time to put in a timely corn crop, and it certainly doesn't take as many days to put the crop in as it used to.

Is there a benefit to planting treated (insecticide and/or fungicide) soybean seed? I'm not sure there is a correct answer, but rather it depends upon several factors. If these protectants do their job, then you could conceivably reduce your planted population, which may or may not save you some money, depending upon the cost of the treatment compared to the cost savings of a reduced population.

There are really two types of fungicides you can select from. One protects against the "water molds", such as pythium and phytophthora. The other protects against rhizoctonia and fusarium seedling diseases. One thing to remember is that these seed treatments are not intended to provide season long protection. They will safeguard the seeds for 2 weeks or so. Metalaxyl will provide help against the water molds. Other products, such as fludioxonil, trifloxystrobin, pyraclostrobin can help against the others.

Which products should you use? Again, it depends upon the situation. The water molds are only found in moist soil conditions. Pythium is favored by cooler soil temperatures while phytophthora is found in warmer soils. Rhizoctonia and fusarium are opportunistic diseases. Which means they infect the plant when it's under stress. This could be from poor growing conditions or herbicide/insect injury or some other concern. Conditions such as early planting, planting into fields that have had incidence of disease in the past, or using poor quality seed may favor the use of a treatment.

Another point to consider is that you can't sell treated seed into the commodity market. Our advice for many years is that if you're going to use treated seed, use that seed first. After all, the first planted fields are more than likely the best candidates. Since it's more likely they will be cooler and wetter than those planted later.

Will insecticide treated seed be of benefit? When insecticide treated seed first became available, soybean aphid was beginning to make itself known. And for those growers who have early season soybean aphid pressure, then the answer is yes. But those areas are primarily in the northern soybean growing regions of the U.S. The soybean aphid does not overwinter here locally. So even though the insecticide treatment is systemic, it won't last season long. The other early season insect that could cause problems is the bean leaf beetle. However, I've only seen a handful of fields that have ever needed protection from early season bean leaf beetle populations.

The best advice on the use of treated seed would be to run some comparisons. Have some treated versus untreated and run them side by side. And better yet, do several side by sides in the same field. Don't compare field to field. The U of I has conducted fungicide treatment studies since 2001. Their results indicated a 0.8 bushel overall response. The response was greater the earlier the beans were planted.

Work recently completed at the U of I Orr Research Center, in Perry (and replicated across the state at the other 5 research farms) investigated the optimal corn planting date and population. This work was conducted to update previous research that was somewhat dated. Other Midwestern Universities research supports this data as well.

Producers have steadily increased corn populations over the years as hybrids have improved in their ability to stand. With this, corn yields have increased as well. Most agronomists would agree that 30K plants (or more) per acre is the optimum population. But at some point, determining the correct population becomes a calculation based upon the price of the seed and the price received for the crop.

Generally speaking, for those higher producing soils, under optimal growing conditions, the closer the final stand is to 35K, the better the results. And for those lower producing soils, populations between 25-30K would be recommended. However, to truly compare economic populations, you must also look at seed cost and the selling price of corn.

Using a seed cost of $2 per thousand ($160 per 80K seeds) and a $4 corn selling price, for those high producing soils, there is an economic advantage for corn population of 35K at harvest (6 bushel yield increase). However, as the seed cost increased, the advantage is reduced. At a seed cost of $2.50 per thousand ($200 per 80K) there is virtually no difference in return between the populations. And as seed cost continues to rise to $3 per thousand ($240 per 80K), the advantage goes to the 30K final population.

Data from the date of planting portion of that study indicate that for central IL, there was only 3 bushels of yield difference between the planting dates of April 1- May 10. With the period of April 11-30 averaging 174 bu/acre, and 10 days earlier or 10 days later averaging 171 bu/acre. This data was generated from 2 sites (Champaign and Perry) over 4 years.

It's getting crunch time. April 1^st is here and past and as I write this the prediction is for rain two of the next 4 days. Many of you have yet to apply dry fertilizer for this years crop, and quite a few corn acres need nitrogen applied as well. The days are going to be long this spring.

Fertilizer prices have really eased since last fall. They're still very high, but at least we've gotten a little break. The question still remains though, how much, if any, fertilizer does this years crop really need? And to answer that question, you'll need a recent soil test. Use that test to determine if your crop will benefit from phosphorus or potassium. Based upon data from IL and IA, soil test phosphorus levels of 20 #/acre will provide 97% of maximum corn yield and 100% of soybean yield. Soil test potassium levels of 250#/acre will provide 94% of corn and 96% of soybean yield.

The question is then what is your current soil test, and if they're lower that these numbers, what will it cost to bring them up. Or if they're higher, how much can you save by not fertilizing. These soil test levels are not all that high. Many fields are probably at or above that level. But if you elect not to fertilize this year, your soil test level will go down as the crop draws up nutrients. Just remember, you can't play this game very long without sacrificing yield, unless you have very high soil test levels.

Nitrogen is the other concern now. With (likely) limited time to perform field work, every minute counts. Do you really want to be pulling a tool bar across the field when you could be planting corn? There are other nitrogen sources available, and this year may be the year to consider them. Liquid UAN (28 or 32%) can be applied with the herbicide. Yes, it can be subject to loss since it's surface applied (unless you incorporate your corn herbicides). However, rainfall within 10-14 days of application will eliminate those loss concerns. There's also a product called Agrotain, that can be used to limit loss as well.

Urea can be applied with the dry fertilizer as another option. Again, the concern is loss. And the concern is greater with urea versus UAN (since only half the nitrogen in UAN is subject to loss whereas all the nitrogen in urea is). We usually recommend that urea be incorporated to reduce opportunities for loss. Or, Agrotain can be used with urea to help reduce loss. Or another alternative would be coated urea, which breaks down via moisture and temperature, taking 4-8 weeks to do so. The only concern with coated urea is that it can float away if surface applied and not incorporated, and heavy rains occur.

Of course, sidedressing is another option. Which is the method that would allow you to reduce your nitrogen rate since you'll be applying closer to the time when the crop would utilize the fertilizer.