Hoegemeyer - the right seed

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.

What are the odds we head into the 2013 planting season with a full soil moisture profile? I can’t say for certain but there is probably a pretty good chance that some areas of our trade area will not, based off where we stand now.

There are definitely both positive and negative attributes associated with soil tillage when comparing to reduced till or no-till.  No-till or reduced till acres generally have a few more disease and emergence issues compared to conventional tilled fields since the soil remains cooler and wetter a little longer in the spring . The increased crop residue can sometimes increase the likelihood for some foliar diseases like grey leaf spot later in the year as well. Ok, that’s enough on the negatives. Now let’s cover some of the positive benefits of no-till/reduced tillage.

Crop residue/stubble left on the soil surface greatly aides water infiltration (rate & amount) into the soil profile. It also helps catch snow during the winter as well as lessens the impact of rain drops on topsoil in the spring which in turn reduces crusting potential.  Aggressive tillage destroys/lessens soil porosity.  Porosity is a term that refers to areas in between soil particles. These areas typically are filled with air and/or water. As porosity decreases water infiltration also decreases along with total plant available water. It’s quite common in the spring or early summer to see water standing after a brief heavy rain in fields that have been tilled black. That water is subject to evaporation as well as runoff depending on slope of the field.  True no-till fields have very diverse soil porosity within their profile compared to fields that are continually tilled multiple times each year. This includes natural structure pores, earthworm channels, and previous year’s plant root channels.  Each tillage pass works to destroy these.

We know tillage is necessary for many fields depending on soil type, amount of residue, and crop, but going into this next year we may need to ask ourselves which fields truly fall into that category.  There should not have been a high potential for wheel traffic compaction during harvest this year compared to recent years since generally we did not experience wet soils during harvest. Is the soil hard?  Yes, but hard and compacted are not the same. Keep that in mind when planning any deep tillage. University studies have estimated that each tillage pass has the potential to remove .25 inch of plant available water from the profile. Going into next year we may need to conserve every bit of moisture we can when it comes.

Figure 1. Water infiltration with five different tillage systems. NT=No-till, ST=Strip-tillage, DR=Deep Rip, CP=Chisel Plow and MP=Moldboard Plow. (Al-Kaisi, 2011).  (Courtesy Iowa State University).  The picture above illustrates a field with a likely relatively high water infiltration rate.

It seems just about every district within the Hoegemeyer trade area has areas suffering from the hot and dry weather we have been subject to this year. Damage varies from minor to total crop loss at this point. Many corn fields are or recently have reached reproduction stages (tassel/silk).  It’s at this time that historically most foliar fungicide application takes place. With the hot and extremely dry conditions across much of the area, foliar fungal disease development is relatively low and/or slow to develop vs. crop stage and calendar date. Most foliar fungal pathogens in corn require moisture to either infect or progress. This is generally produced by high humidity, heavy dew, irrigation, and rainfall that wets the crop canopy for extended periods of time. Gray Leaf Spot, for example, which is one of the most common and potentially damaging foliar fungal diseases, requires somewhere around 12 hours of continued leaf wetting in order to infect. This is hard to accomplish without the aid of humidity and at least average rainfall. There are three sides to the “disease triangle”. They are 1) pathogen, 2)host plant, and 3) environment. A field with high levels of both host and pathogen will not produce heavy disease unless the environment is favorable for disease development. If one side of the triangle is low then it will lessen the amount of total disease present. That being said, southern rust has recently been confirmed at low levels within several center pivot irrigated fields in southern Nebraska which warrants monitoring. If humidity levels begin to creep higher along with the nighttime temperatures, this sporadic yet potentially damaging disease could spread more rapidly.

Disease-free ear leaf of HPT 8345 Hx/LL/RR at Hooper, NE - 7/11/12

With the current relatively low levels of fungal foliar disease, other potential benefits of fungicide applications have garnered some attention. There are various instances and even some 3rd party research trials that have shown a positive yield response to fungicides even in the absence of significant disease and/or when corn is under drought stress, however yield increases in these situations have been fairly inconsistent and much less than when disease is present. The theory is that some fungicides (strobilurins) have a positive physiological effect by aiding in more efficient respiration under hot and dry conditions and can increase water use efficiency.  I feel this is valid information but applications targeted specifically for drought stress purposes alone are hit or miss and are not likely to produce consistent profitable results, especially if drought stress is at moderate to severe levels. An application will not save a severely drought-stressed crop. Fungicide applications should target disease and be timed to provide best results based off disease progression. Most current foliar fungicides have about 21 days of residual activity. Disease has been slow to develop thus far but could increase quicker if the weather pattern changes in the coming few weeks. Therefore this year, fungicide applications taking place toward the tail end of the window (brown silk) may be of more benefit in terms of disease protection than earlier applications.
 

Non-disease related benefits are real but should most often come along for the ride and not be specific targets of foliar disease fungicide applications when consistent yield increases are the main goal. If you have questions regarding fungicides contact your Hoegemeyer DSM or Agronomist. Now let’s get some RAIN!!!!!!!