Give Your Corn a Head Start
By Greg Stewart, OMAFRA


Saving a dollar here and a dollar there. Squeezing out an extra bushel here and an extra bushel there. This is the management approach needed to stay in the black through what looks like another year of tight margins. And you'll be making the critical decisions in the next few weeks.

Ontario corn specialist Greg Stewart offers these quick hitters for a successful crop kick-off. Keep them in mind as you get set for the 2001 growing season.

Aim for uniform emergence, which saves seed and boosts yields. Research continues to show that the more uniformly corn emerges, the more equally plants compete for resources and the higher their ultimate yield. Planter maintenance is the key. Replace worn double-disc seed openers. Be sure bushings and bearings on parallel arms, depth wheels and closing wheels are all in good shape, and units are all running straight. Check that the planter is running level. Consider seed firming devices. If surface conditions are rough or if you're planting on coarse textured soils, be sure to plant firmly into moisture.

Cultivate only once for a seedbed. Where a field was left level in the fall of 2000 and the soil is friable this spring, consider single-pass seedbed preparation. An additional pass may do nothing more than burn costly fuel and delay planting. OMAFRA's Peter Johnson says some growers are showing increased interest in high-clearance S-tines, more teeth on the cultivator, cultivating shallower and beefed-up harrow systems to facilitate one-pass seedbed preparation.

Trim fertilizer rates on the basis of yield risk. Use soil test results and previous crop history for guidance as you identify the most economical fertilizer strategy. In the absence of adequate information, consider trimming nutrients based on potential yield impact. Normally this would mean trimming micronutrients first, then potash, then phosphorus, and finally nitrogen.

Give nitrogen credits where credits are due. Be sure to reduce nitrogen rates when planting corn after red clover, alfalfa, or other legumes. The same goes for fields where manure has been applied. Buying nitrogen you don't need will waste more money this year than ever before.

Include nitrogen in your starter. For years, no-till corn growers have been telling us that 30 lb./ac. of nitrogen in a planter-applied starter band is critical. Recent research indicates that if you are in a side-dress system, getting 30 lb. of N through the planter is critical whether or not you till
(page 11).

Treat seed corn for European chafer. This insect, which looks like a white grub, may become a problem again in 2001 in parts of Ontario. If you're in a potentially high-risk area, seed treatments which include lindane (Agrox B-3, D+L, and D+L PLUS) offer some suppression of European chaffer, and for now may be your only option.

Use atrazine, your old friend. A low rate of atrazine in the herbicide program enhances most broadleaf weed control packages for corn. It is quite often the best bang for your buck. Exceptions to this rule include combinations of atrazine with Peak Plus and/or Summit. These products (which are not registered for tank mixes with atrazine) may be antagonistic with atrazine. Be sure to read and follow labels.

Control weeds early if you can. Weeds that emerge with corn and remain uncontrolled at the 3- to 4-leaf stage of the crop begin to cost yield that you cannot make up with subsequent weed control, no matter how complete. Aim to apply herbicides on the early side of their recommended window. Some products may not be particularly strong on certain weeds but, if applied before weeds get too large, they have a better chance of doing an acceptable job.

Boost plant populations. Increasing evidence confirms that many of today's elite hybrids generate extra economic yield right up into a final plant population range of 30,000 to 35,000 per acre. Narrow-row research across the northern cornbelt quite often includes various plant populations, and the trend is for yields to be optimized at populations higher than 30,000 per acre regardless of row width. This may be especially true for early, small-statured hybrids. Consult your seed company for hybrid-specific recommendations. One exception: Cargill agronomist Pat Lynch suggests that if you can't get enough seed of the best high-yielding hybrid, keep seeding rates on the conservative side, and stretch that hybrid over more acres.

Adjust your planter for small seed size. Weather stress in 2000 resulted in a lot of small seed for this year. Research indicates that small seed should perform as well as large seed in terms of emergence, early growth, and yield. But be sure to properly maintain and/or adjust seed singling
devices in your corn planter. Wrong seed discs, incorrect adjustment of finger tension, brittle or worn brushes, and a range of other deficiencies in planter setup may have more serious consequences than usual when dealing with small seed. Realizing on the second day of planting that your seed
drop is off-target can be costly.

Weigh extra yield against drying costs. As drying costs escalate, later-maturing hybrids which provide higher yields (but at higher harvest moisture) lose some of their economic benefits. In a Michigan study in the 1990s, pushing to the upper end of hybrid maturity rating for a given area almost always produced higher yields but, after deducting commercial drying rates, they almost always produced less in net returns. Drying costs vary but it is a good exercise to push the pencil for your own system. What makes you more money: 130 bushels at 27% moisture or 125 bushels at 24% moisture?

*Greg Stewart is an Ontario ag ministry corn specialist

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