Agronomy Update: Considerations For Spring 2020 Planting
BY DAIRYLAND SEED AGRONOMY TEAM
Fallow Syndrome
Is fallow syndrome “a thing”? Yes, it can be, in certain situations.
What is it?
In general, fallow syndrome refers to slow early season growth of a corn crop following a year in which no crop was grown and the field was kept clean of weeds and had no cover crop planted. The issue really is mycorrhizae – the “branches” of the beneficial fungus that lives in soil. Mycorrhizae are important as they serve essentially as an extension of corn roots and can aid in nutrient gathering by the corn plant. If nothing was planted or grew there last year, the amount of mycorrhizae is likely low. The result can be a lack of nutrients for the corn plant, especially phosphorus, early season.
When might it be an issue?
- If you did not plant a crop last year and did not plant a cover crop and kept the field weed free (by either tillage or herbicide), then it may be an issue for this year’s corn crop.
- If you did not plant a crop but did plant a grass cover crop (wheat, oats, rye, annual ryegrass, etc.), that crop would have supported mycorrhizae and this year’s corn crop will likely be fine. Cover crop does matter – the brassicas are not very supportive of natural mycorrhizae.
What is the remedy?
If you had a truly fallow field last year and are planting corn this year, the best strategy is to make sure you have a good amount of phosphorus in your starter fertilizer. I generally prefer increasing phosphorus in the 2 x 2 starter band, but you might also add or increase phosphorus in the pop-up, or on seed fertilizer amount (be careful of total salt load in pop-up). That will usually feed the corn plant sufficiently until the natural mycorrhizae reestablish in the field.
Spring Planting and Tillage Decisions
In looking at decisions that farmers make, almost all of them are important. It is my opinion that when it comes to crop production, two of the most important decisions that farmers make are:
- The day the ground is tilled.
- The day of the ground is planted.
Deciding when to work the soil can be a game changer for the crop. If you hurry the decision along and work the soil when it is wet, you end up creating a layer of compaction at the depth of the tillage implement. This layer of compaction, if thick enough, may not allow the soil below to dry out and will remain wet. The layer of soil above the compaction zone may dry out and not allow seeds to germinate or roots to go below the compaction zone. If roots do make it through the compaction zone, they will be low in number and migrate to areas where they can go through, which is not a good plan for accessing water and nutrients and or plant standability.
If the weather remains wet after working the soil, the layer of compaction that was created will stop or slow down water moving through the soil profile. If the soil above that compaction zone becomes saturated this can lead to increased ponding and or erosion. If the weather starts to dry out, you may have a layer of dry soil above the compaction zone and wet soil below the compaction zone, which again limits the ability of the plant to bring in water or nutrients in either the wet zone or dry zone.
If you work the ground when it is too dry, you are increasing the rate that moisture is leaving the seedbed. The consequences of low moisture in the seedbed are inhibiting and/or reducing germination and plant growth. Also, by working the soil you are breaking down residue and moving it in the soil profile which can increase the potential for wind erosion.
The day you have the greatest yield potential is the day you decide to plant. Any inputs or factors after that will maintain that yield or reduce it. The rule of thumb I was told to follow to make a good seedbed was to work the ground one day and plant the next day, allowing 18-24 hours for the soil to dry out. If the soil is still too wet to plant, let it dry out and try and plant the next day. If the soil is dry to very dry, work the ground and plant it in the same day. This allows you to take advantage of moisture in the seeding zone.
In some instances, we can’t find that “just right Goldilocks” moment to put the crop in. As we have experienced in the last few years, waiting to let a field dry out may mean not getting it planted, and we may be better off just getting the crop in. Every situation is different, and there is really no one best way to always have that “just right Goldilocks” moment of soil conditions. In some instances, just closing your eyes and not paying attention to soil conditions may be the only option to getting a crop in.
Key Reminders for Planting Soybeans
Planting Depth- Plant 1-1.5” deep. Planting 1” or less increases the likelihood of soybean seed not germinating due to cooler temperatures or lack of moisture.
Soybeans need to take in 50 percent of their weight during the germination process. By not having the proper planting depth, you risk seeds not fully germinating or not having enough moisture to continue to grow. By planting 1-1.5” deep you increase the probability of having adequate moisture for germination and early season growth.
Soil Temperatures- Plant when soil temperatures are 55°F or more, or when air and soil temperatures will be increasing. Soybeans can germinate with soil temperatures at 50°F but are more consistent at 55°F or more. By planting in cooler soil temperatures, you increase the likelihood of Imbibitional Chilling Injury or Cold Shock Syndrome. (Yes, soybeans can get this too). Cool wet soils (less than 60°F) increase the likelihood of seedling succumbing to Pythium and Fusarium. Cool wet soils also increase the potential for Sudden Death Syndrome (SDS) infecting the plant.
Seed Treatments- If planting early, use a quality seed treatment. A quality seed treatment that contains an insecticide will help with germination and protect the seed from early to mid-season insects such as Bean Leaf Beetle, Seed Corn Maggot, Soybean Aphids and Soybean Cyst Nematodes. As stated previously, seed treatments help with cool season seedling diseases such as Fusarium, (early infection of SDS), Pythium and warm season diseases such as Phytophthora and Rhizoctonia.
Research has also shown that treated soybeans tend to have increased plant population of 12-20,000 versus untreated soybeans. Having a product that helps seedlings survive is especially critical when dealing with soybean seeds that have reduced germination percentages like we have this year compared to other years.
Not all seed treatments are equal -- just because something has a pretty color does not mean it is the best investment.
Plant Populations- Recommended seeding rates are 140,000 to 150,000 seeds in a 30-inch row. Soybeans can yield with less than 140-150,000 seeds planted, however, the issues that suggest maintaining a higher seeding rate are:
- Less than ideal planting seedbed
- Hail
- Reduced Germination Scores/Percentages
- Wildlife (i.e. geese, deer, etc.)
- Seed and Seedling diseases
- Soil Types
If you have questions regarding this or other Agronomic issues, contact your local Dairyland Seed Representative. Stay safe and have a successful planting season.
Key Reminders for Planting Corn
Planting Depth:
Plant 1.5-2” deep. Planting less than 1.5” deep, depending on weather and soil conditions increases the probability of the corn seed not germinating due to cooler soil temperatures or fluctuations in moisture in the seed zone.
Corn plants take in 30 percent of their weight in water during the germination process. By not having the proper planting depth, you risk seeds not fully germinating or not having enough moisture to continue to grow. Another forgotten reason to plant 1.5” or deeper, is that many herbicide labels state that to safely use that product, corn needs to be planted 1.5” or deeper, or injury may occur.
Soil Temperatures:
Plant when soil temperatures are 50°F or more, or when air and soil temperatures will be increasing to that level or more. Corn can germinate with temperatures less than 50°F, however, germination is more consistent at 50°F or more. If soil temperatures are in the low 40°F or less, you can increase the incidence of Imbibitional Chilling Injury or Cold Shock Syndrome, which can kill plants and subsequently reduce plant populations/harvestable ears. Cool wet soils increase the incidence of crown rot, as well as seedling diseases.
Starter:
I recommend utilizing a quality liquid starter and zinc to help the plant have an energy source (Phosphorus in the starter) and the ability to help move nutrients and protect the germination process (Zinc). It has been my experience that quality starter and zinc helps the corn “Pop Up” out of the soil and have better early season growth. It is also my observation that this early season growth translates to earlier tassel and pollination which in most cases leads to increased yields, better test weight and dry down.
Plant Populations:
My typical recommendation is to plant 1,000-1,500 more seeds than what is desired for a harvestable stand. Part of this is that not every seed will germinate as well as:
- Less than ideal planting seedbed
- Hail/Greensnap
- Wildlife I.E. Racoons, Skunks, Geese, Turkeys, Deer, grazing Cattle and in some southern states wild hogs may eat seeds or seedlings
- Seed and Seedling diseases
- Soil Types
The ability to variable rate plant has changed how we handle some of these issues, and is a tool that provides a better Return on Investment than increasing the seeding rate across the entire field.
If you have questions or concerns regarding this please contact your Dairyland Seed Representative or Agronomist.
Corteva Technology Use Agreements
All growers with orders for any Corteva Agriscience brand seed product, regardless of crop or trait (including non-GM products) need to have a signed Corteva Technology Use Agreement in place by September 1. Growers should sign the Corteva Technology Use Agreement electronically at www.agcelerate.com. Signing electronically is preferable, however, paper copies are available at www.traitstewardship.com.
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