East-Central and Southeast Iowa Crop Information

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One of the challenges of crop production is to produce the most net crop income. Meeting this challenge is especially important when crop prices are low. Some management decisions come with a cost or a cost reduction as well as a return (hopefully) while others have no net effect on costs but help raise returns.

Several items do not impact costs but impact returns. Many would classify these as "doing the little things right." They include:

• Be timely in planting, in application of fertilizers and pesticides, and in harvesting.

• Resist the temptation to till, apply fertilizer or lime, or haul manure when the soil is too wet. Compaction and/or soil puddling can be a yield robber.

• Be sure soil temperatures and moisture are proper before planting. Poor soil conditions slow germination, which increases the likelihood that seed rots and seedling diseases will become established and reduce stand and, therefore, yield. "Sidewall compaction" inhibits good root growth and can substantially reduce yields.

• Remember that environmental stress on crops and weeds changes both the crop and the weed sensitivity to pesticides, sometimes making crops more sensitive while weeds become less sensitive.

• Calibrate and adjust. From seeding devices to sprayers to fertilizer (including manue) applicators to harvesting equipment, taking time to calibrate and adjust is the quickest way to increase efficiencies and receive maximum benefit from the product.

• Be sure your planter / drill is adjusted for proper seed depth (2 inches for corn, 1.5 for soybean) and that the closing wheels provide good seed - soil contact, crumbling the side wall left by the furrow openers.

• Watch planter speed. As speed increases, seed spacing becomes less uniform, reducing yields.

• Be sure harvesting equipment is properly adjusted and operated to minimize losses and to provide a good quality grain sample.

• Consider both risks and rewards in determining harvest timing. Leaving the mature crop in the field longer may reduce drying costs, but also remember that harvest losses increase during this same time, and bad weather may greatly increase harvest losses.

• Be sure grain drying and storage equipment are adjusted to provide for a good quality product that will store well. Remember,however, that overdrying increases costs and simultaneously decreases returns.

• Communicate often with your landlord(s). Keep them informed about what you are doing and what the costs and returns (economic20conditions) are.

• Identify the limiting factor in the field. Field productivity is limited by the most limiting factor, just as the strength of a chain is limited by the strength of the weakest link. Adding more of something that is not needed will not increase yield and will increase costs. If it is economically justifiable to change (such as soil pH or drainage) or work around (such as soybean cyst nematode) the limiting factor, do it; otherwise, adjust yield goals and inputs accordingly.

• Question each field operation, asking if it will pay for itself.

• Select hybrids / varieties that will produce high economic yields on your soils under your management, even if they are something other that what your dealer(s) would like to sell you. High yielding corn hybrids with high moisture may have a lower net return that a lower yielding variety with lower moisture. Remember disease resistance in situations where diseases may be a problem. If La Niņa continues into late April, drought tolerance may become more important. Genetic diversity spreads risk, so use more than one hybrid / variety. For corn, use at least two if you have fewer than 100 acres, and at least four if you have more than 100 acres. For soybeans, use two or three varieties for 100 acres or fewer, adding one variety for each additional 100 - 200 acres, up to six or eight varieties.

• Be sure to use enough seed, but not too much, to achieve high yields. Shoot for a final corn stand of 30,000 - 34,000 plants per acre and a final soybean stand of 100,000 - 125,000 plants per acre. Remember, when there are more seeds per pound of soybeans, it takes fewer pounds per acre to achieve the desired stand.

• Select pesticides that will give you "the most bang for your buck," which may be different from those your dealer would like to sell you. A survey of the per acre costs of six different herbicides, all with similar chemistry and weed spectrum, revealed a range starting at less the $12.00 and topping at over $21.00.

• Conduct Intensive Soil Sampling. Sample on 2.5 acre "grids," take a minimum of 10 cores (15 is better) and then send a subsample to a certified soil testing laboratory.

• For corn and soybeans, apply no phosphorus fertilizer if good soil tests show phosphorus fertility levels above 16 to 20 parts per million (Bray P1 or Mehlic-3). A little starter fertilizer may still be helpful if the seeds are planted in less than ideal soil conditions.

• For alfalfa, apply no phosphorus fertilizer if good soil tests show phosphorus fertility levels above 21 to 25 parts per million (Bray P1 or Mehlic-3). Regardless of soil test phosphorus levels, 30 pounds of phosphorus at seeding time consistently improves stand establishment.

• Apply no potassium fertilizer if good soil tests show potassium fertility levels above 161 - 200 parts per million (dry test) or above 86 - 120 parts per million (field-moist and slurry test). Again, a little starter fertilizer may still be helpful if the seeds are planted in less than ideal soil conditions.

• If phosphorus and/or potassium levels are below the numbers listed above or if you are fertilizing a different crop, refer to ISU publication PM-1688 A General Guide for Crop Nutrient and Limestone Recommendations in Iowa for guidance on rates.

• If you have livestock, target manure applications to soils where phosphorus and potassium are needed, applying ahead of a grass crop, such as corn or a small grain, to utilize the nitrogen.

• Utilize the "nitrogen credit" when growing corn following soybeans or alfalfa.

• Use the Nitrogen Rate Calculator, Late Spring Soil Nitrate Test and/or the End-of-Season Cornstalk Test to help manage nitrogen fertilizer rates. Poorly drained soils in southern and southeastern Iowa require a little more; see CROP 3073 Nitrogen Use in Iowa Crop Production. If rainfall totals in southern and southeastern Iowa for the months of March, April, May, and June exceed 17 inches, consider adding 50 additional unts of nitrogen fertilizer. Elsewhere in Iowa, if rainfall totals for April, May, and June excced 16 inches, consider adding 50 additional unts of nitrogen fertilizer.

• Take advantage of the "rotational effect" to increase yields and reduce pest management costs as well as some fertilizer costs.

• All normal sources of nitrogen fertilizers are equally effective. The same can be said for phosphorus and potassium fertilizers. Compare costs between different sources, calculating cost per pound of nutrient. Lean toward selecting the least expensive source, remembering also safety, convenience (applying with another product, such as an herbicide), timeliness, and application costs.

• Scout fields closely. Early, accurate detection of problems can lower the costs of managing the problem.

• Use thresholds to determine if and when to treat for insect pests. Diseases often knock down insect populations naturally, so it is important to not treat too soon. Conversely, waiting too long can result in substantial yield loss.

• Be alert for opportunities to use less pesticide (insecticides, fungicides, and herbicides) without losing efficacy. Can herbicide rates be varied across the field as soil types and weed pressures change? Can I change application timing and, thereby, lower rates? Are there opportunities to spot spray?

• Try new ideas / products on a few small areas first, comparing the results on treated areas to the adjacent non-treated areas, before making a large commitment. Seek out information from sources who do not benefit from the sale of the product.

• Keep good records and use them to improve future management decisions.

• Convert unused assets (machinery and equipment) into cash.

• Utilize price and yield risk management tools. Contact Charles Brown or Ryan Drollette for this.

• Scrutinize rental rates. They should be fair for everyone involved. Contact Charles Brown or Ryan Drollette for this.

  Prepared by Virgil Schmitt, Iowa State University Extension Field Agronomist. February 4, 1999. Revised February 25, 2000, September 22, 2001, April 5, 2004, January 7, 2009, April 19, 2016, July 27, 2018.

  If you have any questions, please feel free to contact the Iowa State University Extension Office.

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  Last Update: July 27, 2018
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