Dodge County Crop Report – Aug. 11

Highlights in This Report:

  1. Crop growth stages and yield estimates.
  2. Soybean aphids: Have you scouted yet?

Corn Growth Stages and Yield Estimate Report

Most corn is in the milk to dough stage across the county with replanted corn silking. Our current GDDs suggest a freeze is real concern in our replanted corn crop. I did two in-field yield estimates of irrigated corn in the northwest and central part of the county resulting in 235 (Field 1) and 239 bu/ac (Field 2), assuming 75,000 kernels/bu.

Field 1: The ear count was 32,000/acre (32 total ears in 17’5″ or 1/1000 of an acre) at this field in northwest part of the county. I sampled every 6th ear for a total of 5 ears, striped husk and counted rows around and number of kernels in a row (I don’t count the extreme butt or tip of the ear, only where complete rings form around the ear).

  1. 18 rows, 30 kernels long
  2. 18 rows, 30 long
  3. 16 rows, 32 long
  4. 16 rows, 31 long
  5. 20 rows, 33 long

Average number of kernels per ear was 550.  Assuming 75,000 kernels (good to excellent growing conditions) in a bushel (56 lbs), the yield was estimated at 235 bu/ac (Figure 1).

Figure 1. Irrigated corn field in northeast Dodge County.

Figure 1. Irrigated corn field in northwest Dodge County, estimated yield of 235 bu/ac.

Field 2: The ear count was 33,000/acre at this field in the central part of the county.

  1. 12 rows, 41 long
  2. 16 rows, 39 long
  3. 14 rows, 38 long
  4. 16 rows, 33 long
  5. 16 rows, 34 long

Average number of kernels per ear was 544. Assuming 75,000 kernels (good to excellent growing conditions) in a bushel (56 lbs), yield estimated at 239 bu/ac (Figure 2). The ears were not filled out to the tips at this location,

 

Figure 2. Irrigated field in central Dodge County.

Figure 2. Irrigated field in central Dodge County, estimated yield of 239 bu/ac.

These yields are very similar to current yield forecasts by the Hybrid Maize Model simulations for Concord.

I did four in-field yield estimates of dryland corn in the northwest and central part of the county resulting in 170 (Field 3), 180 (Field 4, some hail damage at this site on June 3), 204 (Field 5), and 210 bu/ac (Field 6), assuming 80,000 kernels/bu (good growing condition during grain fill so far).

Field 3 (dryland field in the northwest part of the county): An ear count of 26,000/acre (26 total ears in 17’5″, or 1/1000 of an acre). I sample every 5 ear in dryland fields for a total of 5 ears, striped husk and counted rows around and number of kernels in a row (I don’t count the extreme butt or tip of the ear, only where complete rings form around the ear).

  1. 18 rows, 35 kernels long
  2. 20 rows, 30 long
  3. 12 rows, 21 long
  4. 18 rows,  29 long
  5. 16 rows, 36 long

Average number of kernels per ear was 522. Assuming 80,000 kernels (good growing conditions) in a bushel (56 lbs), yield estimated at 170 bu/ac (Figure 3).

Field 4 (dryland field in the central part of the county, some hail damage on June 3): An ear count of 29,000/acre in location one and 28,000/acre in location two

  1. 14 rows, 36 kernels long (Location 1)
  2. 14 rows, 33 long
  3. 16 rows, 35 long
  4. 18 rows, 32 long
  5. 16 rows, 33 long
  1. 16 rows, 32 long (Location 2)
  2. 14 rows, 32 long
  3. 14 rows, 36 long
  4. 14 rows, 33 long
  5. 14 rows, 36 long

The average number of kernels per ear were 526 and 486. Assuming 80,000 kernels in a bushel, a yield estimates 180 bu/ac.

Field 5 (Field in the central part of the county without hail damage): An ear count of 27,000

  1. 18 rows, 25 long
  2. 16 rows, 41 long
  3. 16 rows, 44 long
  4. 16 rows, 43 long
  5. 16 rows, 38 long

The average number of kernels per ear was 621. An yield estimate of 210 bu/ac.

Field 6 (Dryland field in the east central part of the county): An ear county of 26,000

  1. 18 rows, 32 long
  2. 18 rows, 39 long
  3. 18 rows, 33 long
  4. 18 rows, 36 long
  5. 18 rows, 34 long

The average number of kernels per ear was 626. A yield estimate of 204 bu/ac.

There has been some questions as to why not use the old fudge factor of 90,000 kernels/bu. The kernel weight from several corn fields in Dodge County over the past few years have been much heavier, ranging from 72,000 to 85,000 kernels/bu, which is similar to a recent report on kernel weight by Bob Nielson, Purdue University Agronomist.

Figure 3. Dryland corn ear from the northwest part of the county.

Figure 3. Dryland corn ear from the northwest part of the county.

Soybean Growth Stages and Conditions Report

Soybeans are in the R5 to R5.5 stage while replanted soybeans are setting pods, R3. The lack of below normal rainfall in late July and early August is showing up through visible drought stress on dryland soybeans this week (Figure 4). Soybean aphid populations have been low, but increasing in frequency and population in fields over the last week (Figure 5). Growers in the area should be scouting their fields to determine aphid populations, especially on replanted fields. Bob Wright, UNL Extension Entomologist, did discuss soybean aphids on the August 8 Market Journal episode (embedded video below).

Figure 4. Dryland soybean fields showing drought stress (leaves will flip to show silvery-green underside to minimize water loss).

Figure 4. Dryland soybean fields showing drought stress (leaves will flip to show silvery-green underside to minimize water loss).

Figure 5. Soybean aphid populations are growing in some fields this week with the cool weather.

Figure 5. Soybean aphid populations are growing in some fields this week with the cool weather.

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Dodge County Crop Report – Aug. 11
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