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Small Grain Fertilizer Sidedress

Rome Ethredge:

This week we are seeing grains growth slowdown due to cold temperatures. Oats are more sensitive to cold temperatures, especially temperature swings.

Oats – cold effects – Rome Ethredge, Seminole Co, GA 2022

Also, seeing some of the older leaves turning yellow and brown due to running out of nitrogen. N in the plant is being translocated to the new growth. Not a big problem but we will take this into account when considering whether to split our sidedressing soon, as it can affect tillering.

Oats – Rome Ethredge, Seminole Co, GA 2022

Next week, the last week in January, will be time to count total stems in wheat and oats to then decide whether to split sidedress N or just wait and apply all of it the second week of February or a little later in North Georgia.  See below, modified from Wheat UGA top 10 sheet.  https://grains.caes.uga.edu/content/dam/caes-subsite/grains/docs/wheat/critical-management-inputs-2021.pdf

Topdress wheat with nitrogen in a timely manner in late winter and early spring.

          During the later days of January, begin counting tillers to determine the need for additional nitrogen applications for the proper tiller production.  If total stem counts (a stem with at least three leaves) exceed 80 or more per square foot, then apply all remaining nitrogen at stem elongation. Usually this occurs during early to mid-February in the southern half of Georgia. In extreme N. Ga, stem elongation may not occur till early March.

If the tiller count is less than 80 per square foot, then apply 30 to 40 lbs of N per acre to encourage tiller production prior to the onset of stem elongation. Complete the topdressing prior to 1st node stage.  Nitrogen rates will vary according to the soil type, variety lodging resistance, irrigation capability, previous crop, etc.  In general, total N rates range from 100 lbs N per acre to 120 lbs N.  Be sure to include sulfur with the nitrogen.  Sulfur deficiencies occur when the ratio of nitrogen in a tissue test exceeds 18:1. Tank mix an approved pyrethroid if aphids are present to reduce the risk to the barley yellow dwarf virus.  Supply 15 to 20 lbs of S per acre if soils are sandy. 

Each stem produces a grain head, so we want plenty for a good grain yield. If seed were broadcast then count stems in a 12 inch X 12 inch area. If drilled in rows, do the math to figure out how far down the row to count. For example on 7.5 inch rows, go 19 inches down the row to get a square foot. Make counts in several representative areas of the field.

This plant has 3 total stems. Some plants will have 5 or more – Rome Ethredge, Seminole Co, GA 2022

This week [and last] in many grain fields we are seeing aphids. But thankfully seeing some parasitism by tiny wasps laying eggs into the aphids and they plump up turn brown and die. Aphid in this photo still had immature wasp still in it as we see no tiny exit trapdoor yet.

Parasitized aphid on small grain – Rome Ethredge, Seminole Co, GA 2022