Oct 1, 2014
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Ask an Agronomist

RSS By: Farm Journal Agronomists, Farm Journal

Have your agronomic questions answered by a Farm Journal agronomist. E-mail us directly at TestPlots@FarmJournal.com, and we’ll respond on this blog to provide an interactive dialogue.

Will dry soil impact my soil pH reading?

May 22, 2014

Question: I’ve read that the extreme soil dryness could affect the soil pH readings.  If this is true, are there any guidelines as to how much?  When I took my soil samples, the soil was absolutely dry with no significant rain in the last half of the growing season.

Answer: Unfortunately there are no solid guidelines.  What we do here is because we have farmers on a two-year, soil-testing regiment I can look back over the past four or five soil testing application scenarios and have a good idea of where the soil pH should be for a particular field.  When I see a field that’s moved sharply acidic, then I look at where I would expect it to be and align it as such. If I had a brand-new field that I didn’t have any history on and I tested it during  drought conditions or last fall and it was extremely acid, I’d apply only half of the limestone the test calls for and then I would make the field verify that it is that acid.  I’d do that by retesting the field in two years. I wouldn’t wait five or six years to verify it.  I’d also set up my budget now so I’m prepared to put the remaining half of the limestone application on the field – if the field does indeed verify it needs the remaining amount in two years.



What Causes Corn Leaves To Turn Purple?

Soil pH is key to phosphorus availability because if soil pH is too high or too low, the nutrient will not be available to the plant.


Residual N Lowers pH

Areas of Ohio and Indiana have enjoyed recent precipitation events that have gone a long way to pull those areas of the cornbelt out of drought.


Evaluate Soil pH and Buffer pH To Determine Lime Needs

Water pH and buffer pH levels can indicate whether you have residual acidity that needs to be neutralized.


Is it too late to plant full-season corn hybrids?

May 08, 2014

Question:  I feel like it’s getting pretty late to plant my full-season corn.  What are you telling growers?

Answer: As prospects for a timely start to spring planting diminish, growers need to reassess their planting strategies and consider adjustments. Since delayed planting reduces the yield potential of corn, the foremost attention should be given to management practices that will expedite crop establishment, wrote Peter Thomison and Steve Culman, with Ohio State University Extension in a recent CORN Newsletter. Although the penalty for late planting is important, avoiding tillage and planting operations when soil is wet should be a higher priority. Yield reductions resulting from ‘mudding the seed in’ are usually much greater than those resulting from a slight planting delay. Yields may be reduced somewhat this year due to delayed planting, but effects of soil compaction can reduce yield for years to come. Keep in mind that we typically don’t see significant yield reductions due to late planting until mid-May or even later in some years. Don’t worry about switching hybrid maturities unless planting is delayed to late May. If planting is possible before May 20, plant full-season hybrids first to allow them to exploit the growing season more fully. Research in Ohio and other Corn Belt states generally indicates that late plantings of earlier maturity hybrids are less susceptible to yield losses than late plantings of the later maturing, full-season hybrids. And, as the planting season drags on, optimal seeding rates for the yield potential of each field should be used. Recommended seeding rates for early planting dates are often 10% higher than the desired harvest population because of the potential for greater seedling mortality. However, soil temperatures are usually warmer in late planted fields, and as a result germination and emergence should be more rapid and uniform. So, as planting is delayed, seeding rates may be lowered (decreased to 3% to 5% higher than the desired harvest population) in anticipation of a higher percentage of seedlings emerging.

When it comes to weed control diversify, diversify, diversify

Apr 29, 2014

Everyone is pretty much in planting mode at this point, understandably so.  But, in the process of getting your corn and soybeans in the ground, keep in mind your options to tackle weed problems early before they can take a bite out of crop yield potential. Mark Loux, Ohio State University weed scientist, has placed several resources on his website to help with understanding diversification requirements in herbicide selection. The videos are each about 10 minutes long and will keep you entertained in the process of providing some solid information and recommendations.

What type of phosphate application in soybeans is best?

Apr 24, 2014

Question: We plant soybeans on 15 inches.  Our soil samples call for phosphate only. Which is better for the plant and higher yields, side-dressed liquid phosphate or broadcast phosphate?  It would seem the plant would use the side-dressed liquid before the broadcast version.

Answer: The best return-on-investment strategy to alleviate low P would be a broadcast application paired with a 2 x 2 starter.

This answer was provided courtesy of Shawn Conley, University of Wisconsin Soybean Extension Specialist.

Do Soybeans Need Nitrogen Fertilizer?

Here's what to know if you are weighing a nitrogen fertilizer application to your 2014 soybean crop. By Stephanie Henry, University of Illinois crop sciences researcher.


Which nitrogen source should I use for sidedressing

Apr 22, 2014

Question: What type of nitrogen do you recommend for sidedress applications in corn?

Answer: For a sidedress application, farmers have a choice in what nitrogen product to apply. Many are asking if there is an agronomic difference between 28% and anhydrous ammonia. At sidedress, as far as the plant’s uptake of the nitrogen, these products will both convert to nitrate for its uptake. The difference between these two is their timing for availability. If you have yellow corn, and you were to sidedress the corn to make it green, the 28% has nitrate, and that turns corn back green faster. With anhydrous ammonia, you create a core and it could be 14 days for the nitrogen to be released from that core. If you are sidedressing green corn, it’ll mineralize back slower and be more stable.  Beyond that, if you have enough nitrogen to keep corn green at sidedress, it won’t make a difference which product you use.

What Are the Nitrogen Requirements for Corn Early in the Season?

Agronomist Ken Ferrie explains why fertility is the foundation for the Systems Approach pyramid and key to increasing corn yields


When Is The Best Time To Apply Phosphorus?

Here's how to differentiate between phosphorus loss from fall-applied fertilizer and loss from spring-applied fertilizer.

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