NOTES FOR 2005
by Greg Stewart, OMAF Corn Specialist

Setting Sites On 2005 Nitrogen Use
For several years now, Ken Janovicek (University of Guelph) and I have been re-analyzing all of the nitrogen fertilizer work that has gone on in the province over the past 40 years. One of the most interesting observations is that a producer can miss the optimum N rate (for that field, in that year) by 20-30 Ibs/acre and not incur any drastic financial losses. And perhaps more to the point, the practice of over-applying nitrogen (i.e./'insurance nitrogen") was no more likely to increase profitability than if you under-applied by a similar amount.
Note: In 2005, if you are facing $2.50/bushd com and $.38/lb N you simply have to leave behind the concept that your corn has to be black-green to optimize profits, it isn't so.

Sidedressers Beware of Early N Impacts
Some of us have preached for some time now about the value of adequate N fertility being provided at planting time, when you are going to sidedress the majority of your N needs in June. At first, this was pretty much a no-till issue, then some further work showed that it was a valid concern in conventional tillage. Overall, it appeared there were 5-6 bushels per acre that you could lose in corn yield, even when you came back in June and sidedressed ample N. 2004 plot results have raised the stakes on this issue considerably. Inadequate N at planting caused huge yield losses for sidedressers (as much as 18 bushels per acre, see Figure 1 for an example). Now the message here is not to stop sidedressing; the aformentioned analysis on nitrogen data is very supportive of the efficiency gains that are a result of sidedressing, particularly on the heavier soil types. Note: However, be aware that adequate N on the planter (i.e., 25-40 Ibs N/acre) is critical to optimizing yields and perhaps also to minimising N requirements at sidedress time.

Hybrid Selection: Too Much Yield - Not Enough Profit
As producers put their hybrid selections together for 2005 they must consider not simply the highest yielding hybrids, but those hybrids which will increase returns, after drying. When corn prices were good and drying prices moderate, the scale always tipped in favour of high yield, the best hybrid for your dollar was almost invariably the highest yielder. If corn prices stay low and drying costs remain high, this scale has shifted enough that growers need to pay increased attention to hybrids that can be very competitive for yield, while significantly shaving drying costs. I am suggesting there is some opportunity for growers to try some radical test plots where they plant hybrids that are significantly earlier in maturity than their farms' CHU rating; perhaps plant them at very high densities and see how they perform against more traditional CHU hybrid selections. You will need to involve your seed representatives on this idea! Finally, planting date information from Wisconsin suggests that high drying cost emphasize a need to switch to shorter season hybrids on May 20.
Note: any good hybrid plan you put together this winter should have a well thought out selection of shorter season hybrids you are going to switch to if planting gets delayed.

Racehorses, Workhorses and Equine Biomass
A study conducted by D. Hicks and J. Lauer, University of Wisconsin, evaluated the frequency at which racehorse or workhorse hybrids appear in the market place. A racehorse hybrid is one, which yields high, in high yielding environments but lower than average in a low yielding environment. In contrast, a workhorse hybrid would be defined as one which yields better than the competition in low yielding environments, but does not perform as well in high yielding environments. Of the 2,563 hybrids that were included in this mid-west study, 86% could not be considered either workhorses or racehorses! For the most part, good hybrids are good hybrids and trying to position them as good in good years, or good in good soil, etc., is not much use to producers. Producers need to use good reliable test results to pick the most elite hybrids for their area. Let's forget about offensive and defensive, workhorses and racehorses and deal specifically with weaknesses that an otherwise excellent hybrid might have.
Note: the last thing we want is a package of hybrids that all have the same weakness, regardless of what kind of horses they are.

Poncho Performance
As we entered the 2004 season Poncho had been newly registered as a seed-applied insecticide for corn, and there was considerable excitement about the potential to boost corn yield with this new product. Numerous research plots and on-farm strip trials were conducted to evaluate the performance of both the high rate product (Poncho 1250) and the lower rate product (Poncho 250). At the time of writing this article, not all of this data has been assembled, but based on what we have gathered, it appears that two factors should be evaluated when considering Poncho use. The first factor is simply the insect pressure that you might expect in a given field.
Factor 1: situations that put you at higher risk of specific insect pressure and hence more benefit from Poncho are: corn after corn (rootworm), corn after sods or pastures, corn after solid manure applications, high residue/no-till situations, areas that have traditionally suffered from specific pests such as European Chafer, and generally the lighter textured soils. It appears that the second factor, when considering Poncho, might be the level of stress that the seed/seedling may experience. More stressful germination and emergence conditions may result in greater benefits from Poncho use at any given insect pressure.
Factor 2: situations that put you at higher risk of delayed or stressful germination and, hence, more benefit from Poncho might be: early planting/cold soils, soils that are poorly drained, planting when soil conditions are less than ideal, etc.
Note: If only a portion of your 2005 seed corn has been ordered with Poncho seed treatment there are some fields and/or situations where the odds of seeing increased returns for your Poncho investment are higher, target your treated seed there.

Population Explosion
Some interesting observations from corn plant density studies out of Wisconsin done by T. Stranger and J. Lauer. Ten sites over 2002-2003 evaluated optimum final populations. Optimum population for highest yields when averaged over all sites was 40,700 plants per acre! If you took economics into account (i.e., cost of seed versus returns from additional yield) the optimum population dropped to 33,400. Still this was 3,400 plants per acre higher than the current Wisconsin recommendation for final stands of 30,000 plants per acre. Our research efforts in Ontario have not shown the need to move up and beyond the 28,000-30,000 final stand plateau. However, there is an ongoing need to continue to examine the optimum planting rates for new genetics.
Note: This is still one of the cheapest and easiest trials to run on your farm; put new elite hybrids, early plantings and your most productive soils to the test by seeding them at 37,000-40,000 seeds per acre.

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