As planting season rapidly approaches, I was trying to think of a cutting-edge agronomy topic to blog about. However, after some thought I have decided to hit on some pretty basic, yet extremely important, topics regarding crop stand and establishment. A typical bag of seed today is loaded with “technology” but it cannot be unleashed without some good old fashioned sound agronomic practices. Once corn and soybean crops approach canopy early in the summer, the vast majority of their yield performance is out of our control. There are a few inputs such as foliar fungicides and insecticides which we still have at our disposal if the situation warrants, but for the most part we are at the mercy of Mother Nature in terms of temperature, rainfall, and sunlight intensity which are key factors for yield. Prior to that however, there are several things that are very much in our control. Rapid establishment of a uniform crop is of utmost importance if we want to even have a shot at approaching full yield potential at the end of the year. The following are a few key points to consider as planting time nears:
1. Proper Planting Depth – As simple as it may sound, shallow planting depth with corn can lead to many significant problems. When seed is planted too shallow, fewer root nodes are able to establish beneath the soil which leads to a restricted and overall lesser root mass. Plants may emerge uneven, lodge later in the year, be more prone to nutrient deficiency symptoms early in the year, have reduced water uptake under drought, and be more prone to rootless corn syndrome if soils are dry early in the year. Anything less than 2 inches is typically not ideal for most soils.
2. Compaction – Anything that limits root development will usually limit yield. Stay out of fields when they are wet. An extra 24-48 hours can make a big difference in regards to side-wall compaction. Avoid excessive down pressure unless needed to ensure proper planting depth. Spike toothed closing wheels have been shown to help avoid side-wall compaction in damp soils by enabling fracturing of the side-wall. However, the best practice is too simply stay out of fields when questionable.
3. Seed Spacing – Most planters are quite capable of accurately planting a wide range of seed sizes if utilizing the correct plates and air pressure. For finger units make sure backing plates are not worn and fingers are all working properly. Unfortunately it is impossible to “manufacture” seed size equally across many different hybrids and varieties. Excessive planter speed works against you. One study I saw showed a 24 bushel decrease in yield when planter speed was increased from 4.5 mph to 7 mph. Across 1,500 acres of corn that is…………….well a lot of $$$$$$$.
4. Early Season Weeds – Start with a clean field if at all possible. Both corn and beans (especially corn) are sensitive to early season weed competition even at low to moderate pressures if the weeds emerge ahead of or at the same time as the crop. Post applications of glyphosate have enabled many of us to clean up messes but in many of these cases significant bushels have already been lost. Most corn acres utilize a pre-emergence herbicide but many soybean growers still rely too heavily on post emerge only. Consider using a pre-emergence herbicide ahead of soybeans at least on a percentage of your acres. Holding back grass and small seeded broadleaves including marestail, waterhemp, and lambsquarter is often very beneficial.
5. Crop Residue – Excessive surface residue can present challenges ranging from poor seed to soil contact to nutrient immobilization. If applicable, set row cleaners low enough to move most residue out of the row zone to ensure hair-pinning does not occur and good seed to soil contact is established. However, avoid setting them too deep. Moving a lot of soil is undesirable, as it creates a place for water to accumulate or wash on sloping fields. Fields with excessive surface crop residues may be more prone to nitrogen immobilization if your sole primary source of N is broadcast surface applied.
* Any portion of yield potential lost early in the season is gone for good with little chance of recovery in full no matter how favorable the growing season is later in the year. The five topics discussed here can go a long way toward ensuring that our crop(s) get off to a good start and maintain optimum yield potential. If you have questions, contact your local Hoegemeyer agronomist, district sales manager or dealer.