Corn Replant Decisions

Consistent rain throughout Knox County has resulted in planting delays.  According to the National Agricultural Statistics Service (NASS) 34% of the corn and 40% of the soybeans have been planted in Ohio, through May 18th .  In  Knox County our corn numbers are higher than that.  For the month of May (through 5/20) we have recorded 7.71 inches of rain at our weather station near Centerburg.  As usual, some parts of the county have received more rain and other areas, not as much.

Some of the corn that has been planted may not survive the cool, wet conditions and therefore may need to be replanted.  Replant decisions in corn should be based on strong evidence that the returns to replanting will not only cover replant costs but also net enough to make it worth the effort.  The following information may help to determine if replanting is justified:

Original target plant population/intended plant stand.  What was your intended plant stand, what is the stand count in the “good” areas of the field.

Plant stand after damage.  To estimate after‑damage plant population per acre, count the number of viable plants in a length of row that equals 1/1000 of an acre and multiply by 1000, for 30 inch rows that would be 17’4″.  Make several counts in different rows in different parts of the field to get a true representation of the field.

Uniformity of plant stand after damage.  If uneven emergence is row to row, that is, most rows are emerged but some are not, replanting will likely not increase yield.  If the delay in emergence is less than two weeks between the early and late emerging plants, replanting may increase yields, but by only 5% or less. Replanting would likely not be economical.  Yet if one-half or more of the plants in the stand emerge three weeks later than the initial plant emergence, replanting may increase yields by about 10%.

Economics – Calculate expected yield from the existing stand and estimated yield from replant.  The table below shows the effect of planting date and plant population on final grain yield. Grain yields for varying dates and populations are expressed as a percentage of the yield obtained at the optimum planting date and population.

For example:   Let’s assume that a field planted on April 20 at a seeding rate sufficient to attain a harvest population of 30,000 plants per acre. On May 28 you determined the stand was reduced to 15,000 plants per acre as a result of saturated soil conditions and ponding. According to the table above, the expected yield for the existing stand (15,000 plants/ac.) would be 81 percent of the optimum. If the corn crop was planted the next day on May 29, and produced a full stand of 30,000 plants per acre, the expected yield would also be 81 percent of the optimum. The difference expected from re-planting is 0 (81 – 81) , which would  not justify replanting costs.  The cost of replanting a field is often the deciding factor. Costs include tillage, seed, fuel (for tillage and planting), additional pesticides, labor, etc. .

Can you get by with replanting certain areas of the field?  This adds several more considerations in addition to those above.  Replanting into existing stands (interseeding) usually creates competition problems with larger plants competing with smaller planes for all needed inputs throughout the rest of the growing season.  Often the smaller plants will turn into weeds.  The best option is usually to destroy the existing stand and start over.

With the continued rains this week it may also be time to consider a Prevented Plant conversation with your crop insurance agent and FSA.

Sidewall compaction from planting into wet soils

Source: Agronomy eUpdates

Figure 1. Sidewall and seed zone compaction in heavy clay soil.

Conducting field work — including planting, tillage, or traffic in general — after wet weather can cause soil compaction, particularly sidewall compaction in the seed furrow. The worst cases of sidewall compaction are seen after a field has been planted when the soil was too wet, followed by a period of dry weather. If the soil stays moist, the roots can usually grow through the walls of the seed furrow. However, if the soil gets dry, the roots can have a harder time growing through that seed furrow wall, and instead grow along the furrow, resulting in what is referred to as sidewall compaction.

With corn, the plants might look fine for a while, but the symptoms of this problem will probably show up after the plants reach several inches tall. Symptoms can mimic drought stress, nutrient deficiency, or both.

Since there are not any good ways to fix sidewall compaction once it exists, the best practice would be to avoid creating the problem in the first place. This means waiting until soils are dry enough to plant. The way to test for this is to dig down to the desired planting depth and make a ball with the soil. Next, see if the ball will crumble or crack apart, or if it deforms like molding putty. If it crumbles, it is ready to plant. If it deforms, it would be best to wait before resuming field operations. Even waiting as little as half a day could make a big difference.

Other considerations

  • Planting too shallow: Planting shallow in wet soil may lead to wheel compaction below the seedling depth. This results in limited downward root growth and seeds growing horizontally.
  • Too much down pressure: If you must work in wet soil, then the down pressure of the row unit and press wheels needs to be reduced to limit compaction around the seed.
  • Soil structure: Tilled soils often lack proper soil structure, causing the standard closing wheel to pinch the sidewalls over the seed from additional pressure. This is frequently a concern in heavier-textured soils, i.e., higher clay content.

Ohio Crop Weather

Source: USDA

Sustained Wet Conditions

Heavy rains last week saturated fields and prevented any large-scale planting activities, according to Ben Torrance, State Statistician, USDA NASS, Ohio Field Office. Topsoil moisture conditions were rated 31 percent adequate and 69 percent surplus. Statewide, the average temperature for the week ending on April 14 was 56.8 degrees, 9.4 degrees above normal. Weather stations recorded an average of 1.86 inches of precipitation, 0.98 inches above average. There were 0.7 days suitable for fieldwork during the week ending April 14.
Farmers reported that with the excess rain, the only field work that could be done was applying herbicide and fertilizing wheat. Oats were 11 percent planted. Winter wheat was 51 percent jointed and winter wheat condition was 70 percent good to excellent. Warmer than normal conditions continued to push fruit crop development.

Ohio Crop Weather – April 1, 2024

Source: USDA

This year’s weather has been temperamental, with temperatures fluctuating wildly between above average to below average over the past few months, according to Ben Torrance, State Statistician, USDA NASS, Ohio Field Office. Topsoil moisture conditions were rated 32 percent adequate and 68 percent surplus. Statewide, the average temperature for the week ending on April 7 was 46.3 degrees, 0.3 degrees above normal. Weather stations recorded an average of 2.67 inches of precipitation, 1.8 inches above average. There were 0.3 days suitable for fieldwork during the week ending April 7. Precipitation last week left fields saturated and brought fieldwork to a stop. Drier weather settled in towards the end of the week, but most fields remained too wet to hold heavy equipment. Oats were 7 percent planted. Winter wheat was 16 percent jointed and winter wheat condition was 67 percent good to excellent. Fruit trees began blossoming in the northern counties after last week’s light frost.

Battle for the Belt:

Season 2 Episode 2- Who Won 2023- Corn or Soybean?

Project Overview

Battle for the Belt aims to answer four questions:

  • Which crop should we plant first- corn or soybean?
  • Which crop has the smallest yield penalty for delayed planting?
  • Can we adjust management practices to mitigate losses due to late planting?
  • How are insects, diseases, weeds, and other factors affected by planting date?

Highlights:

  • Planting window is shrinking
    • Between April 17 and May 15 we have an average of 15 suitable field workdays.
  • Corn yield decrease of 1.75 bushel per day after April 30th.
  • Soybean yield decrease of .5 bushel per day after April 3oth.

Battle for the Belt – Season 2, Episode 1: Kick-Off

Year 2 of Battle for the Belt kicked-off with corn and soybean planting on March 25 at the Western Agricultural Research Station in Clark County: https://www.youtube.com/watch?v=H0ukx_RvOrI&list=PLYlh_BdeqniJ4J-htcJ9Z5MjULk3E8Eqk&index=1

Planting conditions were good with adequate soil moisture; however, soil temperature was in the low 40s at a two-inch depth. Planting will continue at the Northwest Agricultural Research Station in Wood County and Wooster Campus in Wayne County when soil moisture conditions allow.

The Battle for the Belt project seeks to answer several questions related to corn and soybean planting date management in Ohio:

  • Which crop has the smallest yield penalty for delayed planting?
  • Can we adjust management practices to mitigate losses due to late planting?
  • How are insects, diseases, weeds, and other factors affected by planting date?

For both soybean and corn, earlier planting is promoted to maximize yield. However, Ohio has a trend towards a lower number of suitable fieldwork days during planting season. With non-favorable weather, the planting date window is often short and disconnected. Farmers often ‘debate’ which crop should be planted first – corn or soybean. The ‘Battle for the Belt’ project is a field research and extension effort to help address the question, what crop should be planted first – corn or soybean?

This is the second year for the project. Project updates from last year are available on the OSU Agronomy YouTube channel (https://www.youtube.com/@OSUAgronomicCrops). The full playlist can be found here: https://www.youtube.com/playlist?list=PLYlh_BdeqniI7zaFVi1VPCpZ26EQ_YTAT. It includes 33 videos with over six hours of content, addressing a wide range of aspects of this project.

To stay up-to-date with updates, make sure to subscribe to the CORN newsletter (https://lists.osu.edu/mailman/listinfo/corn-out), subscribe to our YouTube channel (https://www.youtube.com/@OSUAgronomicCrops), or follow us on Twitter (@stepupsoy, @OrtezCornCrops).

Wheat Planting Management Considerations for Fall 2023

This year, wheat yields were extremely high across Ohio. In the Ohio Wheat Performance Test (https://ohiocroptest.cfaes.osu.edu/wheattrials/default.asp?year=2023), grain yield averaged between 86 and 126 bu/acre across five Ohio counties. Cool temperatures and adequate subsoil moisture led to a long grain fill period. The long grain fill period coupled with low disease resulted in high-yielding conditions. Mother nature certainly helped us out in 2023; however, fall wheat management is important to set your crop up for success.

Now that we’ve entered mid-September, wheat planting is just around the corner. Here are our key management strategies for this fall:

  1. Plant within the 10-day period starting after the county fly-safe date. It can be tempting to plant wheat before your county’s Hessian fly-safe date (Figure ; however, the best time to plant wheat is the 10-day period starting the day after the fly-safe date. Planting before the fly-safe date increases the risk of insect and disease problems including Hessian fly and aphids carrying Barley Yellow Dwarf Virus. Our wheat planting date field trials have shown no yield benefit of planting prior to the county fly-safe date.
  2. Select high-yielding varieties with high test weight, good straw strength, and adequate disease resistance. Do not jeopardize your investment by planting anything but the best-yielding varieties that also have resistance to the important diseases in your area. Depending on your area of the state, you may need good resistance to powdery mildew, Stagonospora leaf blotch, and/or leaf rust. Avoid varieties with susceptibility to Fusarium head scab. Plant seed that has been properly cleaned to remove shriveled kernels and treated with a fungicide seed treatment to control seed-borne diseases.
  3. Optimum seeding rates are between 1.2 and 1.6 million seeds/acre. For drills with 7.5-inch row spacing, this is about 18 to 24 seeds per foot of row. When wheat is planted on time, the actual seeding rate has little effect on yield, but high seeding rates (above 30 seeds per foot of row) increase lodging and risk of severe powdery mildew development next spring.
  4. Planting depth is critical for tiller development and winter survival. Plant seed 1.5 inches deep and make sure planting depth is uniform across the field. No-till wheat seeded into soybean stubble is ideal, but make sure the soybean residue is uniformly spread over the surface of the ground. Shallow planting is the main cause of low tiller numbers and poor winter survival due to heaving and freezing injuries. Remember, you cannot compensate for a poor planting job by planting more seeds; it just costs more money.
  5. Follow the Tri-State Fertilizer Recommendations for Corn, Soybeans, Wheat, and Alfalfa (https://agcrops.osu.edu/FertilityResources/tri-state_info).
  6. Apply 20 to 30 lb of actual nitrogen per acre at planting to promote fall tiller development. A soil test should be completed to determine phosphorus and potassium needs. Wheat requires more phosphorus than corn or soybean, and soil test levels should be maintained between 30-50 ppm (Mehlich-3 P) for optimum production (Table 1). Do not add phosphorus if soil test levels exceed 50 ppm.

Table 1. Wheat phosphorus recommendations from the Tri-State Fertilizer Recommendations for Corn, Soybeans, Wheat, and Alfalfa.

Table 1. Wheat phosphorus recommendations from the Tri-State Fertilizer Recommendations for Corn, Soybeans, Wheat, and Alfalfa.

Soil potassium should be maintained at levels of 100-130 and 120-170 ppm (Mehlich-3 K) on sandy soils (CEC < 5 meq/100 g) and loam/clay soils (CEC > 6 meq/100 g), respectively. If potassium levels are low, apply K2O fertilizer at planting, depending on soil CEC and yield potential (Table 2).

Table 2. Wheat potassium recommendations from the Tri-State Fertilizer Recommendations for Corn, Soybeans, Wheat, and Alfalfa.

Table 2. Wheat potassium recommendations from the Tri-State Fertilizer Recommendations for Corn, Soybeans, Wheat, and Alfalfa.

Soil pH should be between 6.3 and 7.0. In Ohio, limed soils usually have adequate calcium and magnesium.

Field Observations Thru May 26

Alfalfa

Most of our first cutting is complete.  If you have not mowed yet continue to monitor for alfalfa weevil.  As regrowth starts begin to monitor for potato leafhopper.

Corn

What a difference a week makes.  Most of our corn is now planted and about 50% has emerged.

 

Soil Crusting

Soil crusting is still an issue.  Continue to scout for emergence problems.  A few fields saw a return of the rotary hoe to help break the crust and aid in crop emergence.

Beans

Like corn, bean planting is coming to an end.  Soil crusting is also an issue in many of our bean fields. Continue to scout these fields for emergence problems.  Read more here.

Slugs

Slug damage was a problem early in a few fields.  The forecasted warm and dry weather should help to eliminate this problem.

 

Wheat

Scout for disease and insects:

Cereal Leaf Beetle Scouting Information

Powdery Mildew Scouting information

Head Scab Scouting Information

Most of our wheat is nearing a time when a decision must be made.  All of the wheat fields that I have looked at are showing no signs of disease pressure.  Here are some factors to consider

  1. No existing disease pressure
  2. The head scab forecast system is showing a very low chance of scab
  3. Fungicide cost can range from $12 – $18/acre plus application charges
  4. New crop wheat price is hovering around $6.20/bushel
  5. The 6 – 10 day precipitation outlook is for below normal rainfall and mild temperatures.

READ MORE HERE

If You Planted and Heavy Rainfall Affected Your Fields…

Source: Osler Ortez, Laura Lindsey, OSU Extension

According to the USDA-NASS report for the week ending 05/14/23, 26% of Ohio’s corn and 28% of Ohio’s soybean acres were planted. About 8% of corn and soybean was reported emerged.

Heavy rainfall (1-2 inches of rain) events were reported for some areas of Ohio last week. Heavy rainfall can negatively affect planted and emerged fieldsplanted and non-emerged fields, and yet-to-be-planted fields. If you are in one of the areas with concerns about heavy rainfall, below is a summary of topics that one should consider (Table 1).

Table 1. Topics, considerations, and takeaways for corn and soybean fields are affected by heavy rainfall this season.

The bottom line is that seed damage due to abiotic factors can affect seedling vigor, plant growth, and crop establishment, ultimately reducing crop stands and yields. We recommend weighing the above considerations if you are affected by heavy rainfall this crop season.