Field To Yield: Crops & Comments

Geoff Reeves
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Agronomy topics curated by Geoff Reeves

  1. 5h ago

    Cover Crop Nitrogen Mechanics

    Your winter cover is already planted, but it hasn’t decided your spring nitrogen bill yet. The kill date is still in your hands. This episode explains what happens to cover crop residue in the soil and why the same field can give your next crop nitrogen or tie it up. We put real dollar figures on cover crop N credits for Southeast corn, cotton and soybeans. The 20-to-1 line — Soil microbes need nitrogen to break residue down. Residue richer than about 20–25 parts carbon to 1 part N releases nitrogen. Leaner residue borrows it from your soil first.Two weeks makes the difference — Rye goes from neutral to tying up N between boot and heading, often right at corn planting. Kill at boot or earlier, 7–14 days before planting.Rye ahead of corn — Move 25–30 lb of your planned N to the planter, below the residue. If the rye got to heading, add another 20–30 lb.Clover credits don’t agree — Southeast university credits range from 0 to 100 lb N. Piedmont field data show corn actually recovers about 36–40 lb. Plan on about 45 lb and check it with a soil nitrate test before sidedress.Cotton and soybeans — Cotton after rye needs its extra N by about three weeks after emergence, not at pinhead square. Soybeans make their own N, so decide their kill date on weeds and insects.Count litter once — Poultry litter spread on a growing cover becomes part of the cover’s N, not a separate credit.The honest math — At about $0.75/lb N, a 45-lb clover credit is worth roughly $34/A, against about $45–$80/A to establish the clover. Plant covers for erosion control, moisture, weeds and leaching. The fertilizer savings alone usually won’t pay for them.

    Cover Crop Nitrogen Mechanics

  2. 6d ago ·  Bonus

    The Real Effect: Brazil

    The Real Effect: How Brazil's Currency Moves Your Crop Prices When Brazil's currency dropped about 10% overnight after its presidential election, soybean futures slid with it. Nothing changed in a single US field, so why did your price move? This episode follows the money from a farmer in Mato Grosso to the grain bid at your local elevator, and shows where the trail goes cold for Southeast growers. The cash-register effect — A weaker real means Brazilian farmers get more of their own currency for every bushel, so they sell harder and Brazil can export cheaperFutures vs. basis — The currency hits Chicago futures, but Southeast basis often holds up thanks to strong local livestock demandCotton's exposure — Brazil is now the world's top cotton exporter, which makes cotton the Southeast crop most exposed to swings in the realCorn's cushion — Why hog and poultry demand anchors local corn bids in a region that has to ship grain inThe fertilizer angle — Brazil imports nearly all its potash, and what a weaker real could mean for spring 2027 input pricesWhat to watch — Brazil's central bank decision on November 4, Chinese purchases, and how fast Brazilian farmers sell the new crop

    The Real Effect: Brazil

  3. Oct 27

    Soybean Color Genetics

    Tawny vs. Gray: Does Soybean Color Really Matter at Harvest? Drive past a mature soybean field and you’ll notice the color right away: silver-gray, golden tan, or that dark reddish-brown a lot of Southern growers still swear by. The old saying is that darker beans hold up better in a wet fall. We dig into the genetics behind field color and look at what the research says about whether it has anything to do with weathering and seed quality. It’s mostly the hairs — Field color comes mainly from pod pubescence, which is tawny, light tawny, or gray, laid over a separate pod wall color of tan or brown.One gene, one pigment — Tawny hairs carry a flavonoid pigment that gray hairs can’t make. A single gene flips that switch.Putting the old belief to the test — Mississippi State left a variety trial standing in the weather for weeks past maturity. Color showed no link to seed quality, but varieties differed a lot from one another.Why the preference stuck — Popular old tawny varieties carried other good genes, maturity timing varied, and mold-darkened gray fields just look worse from the truck.What to look at instead — Pick varieties on OVT seed quality, Phomopsis and purple seed stain ratings, shatter, green stem, and maturity fit. Then use color to spot off-types.

    Soybean Color Genetics

  4. Oct 20

    Bt Corn

    Why does a Piedmont corn grower have to plant a 20% non-Bt refuge when an Iowa grower only needs 5%? The answer is corn earworm, the same insect that becomes cotton bollworm. It has already beaten most of the Bt proteins in our corn. Geoff and Glenn break down how refuge works, whether it's still doing its job, and what it means for your seed order. Why 20% here and 5% up north: Earworm feeds on corn, then moves to cotton and soybeans in the same season, and Bt isn't strong enough to kill it outright. The Corn Belt's 5% rule was built around European corn borer, which lives almost entirely on corn.How refuge actually works: Non-Bt corn produces susceptible moths that mate with rare resistant survivors, which keeps resistance genes diluted. That only works if the refuge is close by and planted at the same time as your Bt corn.The rules in the Carolinas: Every county in NC and SC counts as a cotton-growing area. Refuge-in-a-bag doesn't count here, so you need a separate 20% non-Bt block within half a mile.Where resistance stands: Earworm is now resistant to the older Cry proteins across the South. Vip3A still protects ears, but resistance genes are already showing up, and that same protein protects your neighbor's cotton.Does refuge cost you money?: NC State on-farm strip trials found no profit difference between a well-chosen non-Bt hybrid and 100% Bt corn. Hybrid choice mattered more than the trait.What's coming from EPA: Proposed changes, including requiring Southern growers to buy refuge seed along with their Bt seed, are still on the table but haven't been finalized.

    Bt Corn

  5. Oct 13

    Wheat Planting

    The wheat window is open in the Piedmont, and the two biggest decisions you make this month are when to plant and how much seed to drop. This episode walks through how a wheat plant builds tillers, why the ones formed in the fall carry the crop, and what you are trading away when you plant too early or too late. The focus is the North Carolina Piedmont, with a look at how the guidance changes from Virginia to the Gulf. Fall tillers make the crop — NC State research found tillers formed before January 1 produced about 87% of grain yield. It takes 300 to 400 heat units after planting just to get the first tiller started.When to plant — NC State’s window opens about a week before your average first freeze and runs roughly three weeks. For most of the central and southern Piedmont, that means starting around mid-October and finishing before Thanksgiving.What late planting costs — Virginia Tech on-farm trials from 2023 to 2025 made about 75 bushels for October plantings, 66 for mid-November, and 52 for late November.Seeding rate in seeds per foot of row — On 7.5-inch rows, NC State’s range is roughly 21 to 28 seeds per foot of row: low end early in the window, high end as you slide into November. The episode also covers why setting the drill by the bushel can leave you well off target.More seed won’t buy back a late date — In a Union County on-farm trial, seeding rate didn’t change yield at any planting date, but planting date did. That’s one season at one site, and the episode says so.Hessian fly and aphids — Planting early raises the risk from both, including the aphids that carry barley yellow dwarf. North Carolina has no dependable fly-free date, so the episode covers rotation away from old wheat stubble, resistant varieties, and when a seed treatment pays and when it doesn’t.

    Wheat Planting

  6. Oct 6

    Molybdenum

    Nobody soil tests for molybdenum, and in the Southeast you don't need to. Your pH number is doing that job. We dig into how Mo behaves in our soils, when soybeans actually respond, and whether there's anything to the idea that Mo can protect wheat falling number. pH is your Mo test — Molybdenum works backwards from most micronutrients. Acid soil locks it onto iron and aluminum oxides, and lime releases it. No Southeast lab offers a calibrated Mo soil test.Clay vs. sand — Piedmont red clays hold a Mo reserve that liming frees up. Coastal Plain sands have less to release, and pushing pH above about 6.2 there invites manganese deficiency.Why soybeans care — Nodule bacteria need Mo to fix nitrogen, so a Mo-short soybean looks N-deficient with poor nodulation.When seed treatment pays — On fields limed to target pH, expect no response. On acid, un-limed ground below about 5.8, a low-cost Mo seed treatment is cheap insurance, though it's no substitute for lime.The falling number question — Mo helps the plant make ABA, the hormone behind seed dormancy, and Mo-starved wheat sprouts more easily in lab studies. But no study has ever measured Mo's effect on falling number, and none has tested soft red winter wheat.What actually protects falling number — Variety choice and prompt harvest. Don't spend money on foliar Mo for wheat quality.

    Molybdenum

  7. Sep 29

    Nematodes

    They're the yield robbers you can't see, and the only way to know what's in your fields is to go looking before the ground gets cold. This episode breaks down what's feeding on Carolina row crops, how to sample for it this fall, and what to do about it before you buy a single bag of seed for next year. Fall is the window — Populations peak near harvest and crash over winter as they retreat to eggs the lab can't count. Sample late August through November; a winter sample will lie to you.How to pull a good sample — 20-plus cores, 6 to 8 inches deep, in the old row where the roots were. Keep each soil type separate, keep the bag cool like a jug of milk, and get it shipped inside two days.Where to send it — NCDA&CS in Raleigh for NC growers, or through your county agent to Clemson's Blackville lab in SC, where the Corn, Soybean, and Cotton Boards are covering the cost again this year.Know which one you've got — Southern root-knot, peanut root-knot, Columbia lance, reniform, sting, and soybean cyst all behave differently, and the standard assay won't tell root-knot species apart. Soil texture is your biggest clue.Sand tells the story — Sting won't do much without 80 percent sand and Columbia lance wants the same coarse ground, while reniform leans toward the finer stuff. Piedmont clay data is thin, and we say so.Guava root-knot is the one to watch — It's regulated in NC, it beats the root-knot resistance built into cotton, and confirming it takes a molecular test, not a look under the scope.Resistance and rotation before chemistry — Cotton's Rk genes, soybean's Rhg1 and Rhg4, and peanut resistance bred in from wild Arachis usually outperform anything you can buy in a jug, and they cost nothing per acre.Why PI 88788 is wearing out — Almost every SCN-resistant soybean on the market traces to one source, and populations are learning their way around it. Rotating to Peking-type resistance matters.Rotation works until it doesn't — Cotton and peanut break each other clean, and corn or small grains starve out cyst nematode. But sting, lesion, and stubby-root eat nearly everything, so no rotation saves you there.Where wheat fits — Small grains break cyst and peanut root-knot but host southern root-knot and sting, so wheat into double-crop beans can carry a population straight through the year.Modes of action, plainly — Fluopyram shuts down mitochondrial complex II, abamectin locks open chloride channels, aldicarb and oxamyl hit acetylcholinesterase. Different tools, different jobs.When nematicides don't pay — Trials across the Southeast show fumigation often loses to cheaper in-furrow and seed treatments, and on corn and beans the margin frequently won't carry the cost at all.What it's actually costing you — Root-knot was the number one yield-reducing cotton disease nationally in 2023, ahead of reniform and seedling disease. This isn't a sideline problem.The honest gaps — Piedmont threshold data, independent validation on biological nematicides, and published per-acre cost figures are all thinner than anybody would like.

    Nematodes

  8. Sep 22

    Soil Testing, Part 3: Phosphorus

    We've covered pH and potassium. Now the nutrient that behaves like nothing in a Corn Belt textbook. On our Piedmont clays, phosphorus is hard to build, slow to move, and — on thousands of acres with a litter history — already piled up higher than any crop can use. Geoff and Glenn dig into why that happens, what your soil report is actually telling you, and where the money is. Why P sticks — Aluminum and iron oxides grab phosphate and slowly bury it, which is why a heavy application on a low-testing field doesn't all stay available.The lime connection — Getting pH into the low 6s makes your existing phosphorus work harder. Part 1 pays a dividend here.Index isn't ppm — NCDA&CS reports a P-Index, not parts per million. Compare it to a Midwest bulletin and you'll reach the wrong conclusion.Where the line actually is — The state recommends zero P above a P-Index of 50, and the real critical level on Piedmont ground is closer to 10. Most fields in North Carolina are well past both.The litter math — Poultry litter runs about 1:1 nitrogen to phosphate. Corn wants closer to 1.7:1, grass 3 or 4 to 1. Fertilize for nitrogen and you over-apply phosphorus every single year.Starter fertilizer, honestly — NC State tested corn and cotton across all three regions on very high P soil and found no response. Keep the rig, change what's in it.When the soil quits holding — Those binding sites are finite. Fill them up and phosphorus starts leaving in runoff. That's the chemistry behind PLAT and P-based application limits.Drawdown reality — Crop removal will bring a loaded field down, but plan on a decade or more, not a season.The actual answer — Move the litter to your low-testing fields and buy nitrogen for the high ones. Nobody needs to quit using litter.

    Soil Testing, Part 3: Phosphorus
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Agronomy topics curated by Geoff Reeves

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