From Tim Harbaugh- Agrigold Seed Sales Rep

Tim Harbaugh
Agrigold Seed Sales Rep.
Tim.Harbaugh@agreliantgenetics.com
563-580-1212

Top 10 List to Achieving Maximum Yields
Although drought is on everyone's mind going into the 2013 growing season, there are certain things that occur every year in one corner or another in Eastern Iowa. Somewhere there will be wet planting conditions or dry planting conditions or black cutworm or rootworms or numerous other challenges.  The following is a list put together on what I feel are the most common situations that we should look to control in order to achieve maximum yields.

1. Genetic Selection - One of the biggest decisions that needs to be made is also one that we have the most time to ponder and results in arguably the biggest payoff. Regardless of the sales add that you see, as a farmer you know your fields better than anyone else. The light spots, the poor drainage, the underlying layer of gravel - have all been documented in your mind and records. Different families and individual hybrids within these families will handle these situations as well as planting populations in their own way, pick your CS's brain thoroughly on placement.
2. Soil Conditions - With a lack of soil moisture, tillage passes become even more important. The main goal no matter what approach you select is to get a seed bed that provides good seed to soil contact with uniform moisture and temperature. No-till is garnering a lot of discussion to conserve water, as is strip till which works and warms the planting zone while leaving inter row soils alone. The most common practice to this day though exercises some sort of tillage across the field where two main options come into play. Till early in the year when the temps are lower to reduce evaporation loss while increasing the potential for erosion, or till shortly before planting to reduce erosion risk and aid even emergence but take more of a hit on evaporation.

3. Barrier Free Root Zone - Average to above normal rainfall covers up many issues including compaction layers within a corn field if spaced out evenly. I have found myself shaking my head in disbelief upon digging, or trying to dig up a root ball on an excellent looking corn plant with a terrific ear only to find half a root mass at best in wet years. Most of the time during average to below precipitation years root mass will make all of the difference in the world, just like in 2012. We don't yet know what we will get this year but the majority of the time a hard pan will seal a plant's fate and is easy to find, just try to dig it up. Alleviate these compaction layers if at all possible with deep tillage, cover crops, or increasing organic matter before another dry year takes away that acre's profits.
4. Seed Placement - Every year seed placement becomes an issue as a general rule of thumb - no matter the moisture level in the field. Corn needs to imbibe about 30% of its dry weight in moisture for growth to begin so putting the seed in uniform moisture is a must. Proper row cleaner adjustment to clear away debris that wicks out moisture or clods that create air pockets is a necessity. Closing wheels will need to be adjusted to achieve the best results as crop rotation, previous tillage, planting depth, soil type, moisture level, or even time of day changes. Without proper seed placement and uniform emergence, your final ear production per acre will suffer and the more fixed eared hybrids will take a beating.

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Uneven emergence in dry soils leading to as much as a 3 leaf collar difference.

5. Insect Control - Early in a plants' life any stress can greatly reduce the possible ear size that could be grown. Whether it be wireworms, white grubs, seedcorn maggots, grape colaspis, nematodes, rootworm larvae or even the pop up out of nowhere black cutworm, these insects can stunt or kill seedlings, limiting your effective ear producing plant population. Seed treatments such as Poncho/Votivo handle many of these, granular insecticide is a major part of controlling rootworms, and good regular scouting is needed to catch cutworm outbreaks.

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Black Cutworm

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Wireworm

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Rootworm Larvae

6. Proper Herbicide Applications - In a study conducted at the U of MN from 2004 to 2006, weeds killed at 7 inches vs. 5 inches resulted in a 12 bushel yield loss. When herbicide application (in this case glyphosate) waited until weeds were 9 inches tall, it cost the grower 27 bushels vs. the 5 inch weed height. In a different study conducted at the U of WI from 2006 to 2007, weeds sprayed at 4 inches removed from 12 to 26 # of Nitrogen from the soil while 12 inch weeds took 25 to 67# of Nitrogen from the crop. This interval from 4 to 12 inches equated to a difference in yield of 12 to 18 bushels lost.

7. Adequate N Supply - As one of the macronutrients needed for a good crop of corn, both amount and availability of Nitrogen throughout a corn plants' life is of major concern. I am personally in favor of at least two forms (or two application passes) of Nitrogen each year to feed the crop which will hedge your bet against a particular weather pattern stealing one form (or trip). Anhydrous applications will undoubtedly be made at a deeper level in 2013 to assure proper seal so UAN as a chemical carrier (~30#) is a good option to feed the plant until its roots get into that layer where the NH3 was placed.

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N deficient corn leaf

8. Pollination Protection- This past year Japanese Beetles made a hard charge onto the scene and almost made us forget about the other silk clippers that have widened their area of attack yet another year, rootworm beetles. Either of these can cause a complete pollination failure by clipping silks to within ½ inch of the ear if untreated on what otherwise appears to be a healthy plant. In 2012, silks that were clipped regenerated even more slowly than normal because of the lack of moisture within the plant, making spray timing that much more imperative. Those who found these issues before it was too late put big money in their pocket, but remember, each maturity within the same field runs the risk at a different time.

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Japanese Beetles

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Lack of pollination from silk clipping

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Rootworm Beetles

9. Late Season Disease Control - As we finally get our corn crop into the ear fill stage, undoubtedly some leaf disease will pop up and cause us problems. Cooler seasons generally give us Eyespot, Common Rust and Northern Corn Leaf Blight while warmer ones throw Gray Leaf Spot and sometimes Southern Rust our way. Once again knowing the history of your fields and the likelihood of a hybrid to contract certain diseases can lead you to applying a fungicide and extending your crops' life. Mind your labels though as well as adjuvants and crop maturity so that ear formation isn't suddenly halted with premature applications.

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Gray Leaf Spot

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Northern Corn Leaf Blight

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Common Rust

10. Timely Harvest - As the year winds down, make sure your diligent checking of fields doesn't halt just because the green color is gone. Applying the "push test" or "pinch test" to check a corn's integrity is an easy way to save yourself from losing bushels due to down corn and fighting unnecessary volunteer corn the following year. Stalk rots are weak pathogens that are opportunistic in nature, attacking already stressed corn when conditions are right. Just before harvest is a perfect time to once again consult with your CS to get a handle on which hybrids should most likely come out early.

Reference: Stahl, Liz U-M Extension. "Timely Weed Management Protects Corn Yields." Wallaces Farmer. 30 April, 2010.