Hoegemeyer - the right seed

It is already mid April and you’re ready to plant corn!  Why is soil temperature so important?  We all know that soil temperature should be hovering in the 50 degree area for corn to germinate but what many do not know is that it takes two things in the right amounts to properly start the corn seed germination process.  One is the right temperature and secondly, the seed needs to absorb around 30% of the seeds weight in water to begin the process in cooperation with soil temperature.  (Note: soybeans need to absorb about 50% of the seed weight.) 

Please consider this!  Many of the near term weather forecasts I have heard are saying cooler temperatures and some form of moisture which potentially may not allow near term soil temperatures to rise or stay like we hope it should.  We have all heard of seed lying in the ground for up to three weeks before it emerges hence we may reason that with the help of today’s seed treatments the seed still germinates and produces corn … so what can happen? 

Keeping in mind it takes the right (1) temperature and (2) amount of water to start germination, problems can arise in cool soil conditions!  Even though the temperature is not adequate to start germination the seed still continues to absorb water through the germ area of the seed. The amount of water absorbed will go above and beyond 30% of the seeds weight to the point where the seed expands so much that it breaks the clear pericarp layer surrounding the seed.  The longer seed lays in cool ground with its pericarp broken is like opening the barn doors wider to allow soil / disease pathogens unlimited opportunity to enter the seed.  These pathogens may increase the possibility of seedling damping off and or surviving plants will be at a greater risk of disease infection that may show up later in the year in the form of fungal diseases like stalk rot or bacterial problems or weaker, susceptible yield robbed plants.      

Consider that we still have a lot of time to plant for the best yield potential.   

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.

The Midwest has recently experienced a massive blast of cold weather from the north.  This cold weather has frozen the top few inches of soil and the soil may remain that way until spring.  If temperatures are mild, there may be an opportunity to get into the field and pull soil samples. 

You can either hire someone to collect soil samples or you can do it yourself.  If you are well acquainted with a particular piece of dirt, you can save yourself some money and get quality soil samples yourself.  All you need is a shovel, bucket, paper lunch bags, and a pen.  For example, a grower has been farming a particular farm for many years and is well aware of areas in the field which are excellent, fair, and poor (sloped, level, rocky, fertile, drained, wet, etc.)  These are called management units.  This farmer has established 5 management units (3 to 6 recommended) on this field because of previous knowledge of his farm.  The farmer takes 15 random soil samples to a depth of 8 inches in one management unit with his shovel, mixes them together in his bucket, then labels and fills one paper bag with that soil sample.  This process is duplicated across all management units, and bags are then sent to the nearest laboratory for analysis and fertilizer recommendation.

For more precise soil samples, grid sampling can be done to provide better information on soil variability throughout a field.   Many growers are reluctant to spend many hours getting down and dirty in a field to grid sample the entire field with 1-acre samples.  Who can blame them as it is a tedious process which requires a fancy computer program, a handheld GPS unit, and pulling many soil cores which a farmer would rather let an agronomists do.   Grid sampling done for optimum accuracy includes 1-acre samples, 2.5-acre samples are acceptable, and 4 acre grid samples are done at more economical prices with reasonable results.  When a grid sample is done, 5-8 core samples should be pulled at 6-8 inches per sample.  This data can provide a good map for many years; 10 – 20 years for organic matter and CEC; 5 – 10 years for pH; and 5 years for P, K, and Zinc.  Include these grid samples into a GPS unit, along with previous years yield data, to create a precise fertilization and planting population program to maximize yield and efficiency on a farm.

If the ground is not frozen deep into a soils profile, then there still may be a chance to do some soil sampling across your acres for fertility analysis this fall.  Knowing the nutrient losses and needs on your farm will substantially help improve profit by reducing the cost of over-application of valuable fertilizer where it is not needed and increasing profit by increasing yield potential by providing more fertilizer where it is needed.  If the weather warms most soils should mellow up enough to get a shovel into the ground.  If not, do not worry, you can always grab an auger drill bit from your local farm supply store and tediously retrieve soil samples that way.  Enjoy!