Seminole Crop E News

Agricultural News for Farmers and Agribusiness in SW Georgia

Archive for the ‘Fertilization’ Category

Sulfur in Corn

Posted by romeethredge on April 26, 2014

Our rainy conditions have leached some nutrients  in corn fields and one of them is Sulfur. Sulfur is a nutrient that is not needed in high amounts but is needed by plants, especially corn. Sulfur is classified as a secondary element.   In one of my soils classes at UGA we talked about that when we burned lots of coal, sulfur dioxide was put into the air and made it to our fields, but now we have to supply more than long ago.

Sulfur is essential in forming plant proteins and deficient plants look very pale yellow especially in new growth areas as it is not well translocated to new growth as some nutrients are. Cold wet soils delay the release of sulfur from organic matter as well.

Also, we can run into a problem when our N:S ratio is too high. In other words we need a certain amount of sulfur to go with our nitrogen and if we don’t have it then the Nitrogen doesn’t do as much good for the plants as it should.

In corn we want this ratio to be less than 16:1 or we don’t have enough sulfur in the plants. This tissue sample taken last week in a very yellow corn field shows this problem.

Fullscreen capture 4262014 94449 AM.bmp



Posted in Corn, Fertilization | Tagged: , | 2 Comments »

Corn is Yellow – Top 4 Reasons

Posted by romeethredge on April 18, 2014

Some of our corn is just coming up good but most is at V2 and the oldest is at V5 growth stage. Most of it has a yellow color for several reasons, here are the top 4 in my mind.

Leaching rains have depleted nutrients such as Nitrogen and perhaps Sulfur and it’s time to add more but it’s too wet to run the spreaders or liquid rigs to put it out.

Another reason is the erratic cool weather, with some very cool nights such as the unseasonable 38.5 degrees F on April 16th at the Donalsonville weather station.

A third reason is the wet soil. The soil is staying so wet that we are loosing soil oxygen and that is bad for roots. The plants are affected.

Reason number 4 goes along with the poor growing conditions, nematodes. Damage from nematodes in corn shows up much worse when we have poor growing conditions. Nematodes affect the roots and therefore plant growth and health.

A last reason that we won’t count is that where over the top herbicide applications have been made, that many times further yellows corn for a few days as well.



Posted in Corn, Fertilization | Tagged: | 6 Comments »

Question of the Week – Pop up Fertilizer – 2 X 2

Posted by romeethredge on March 8, 2014

Last week I had a photo of a corn planting rig and my question was about the set of round coulters out  in front of the set where the seeds are coming out. That set of coulters go into the soil about 2 inches deeper than the seed will be placed and about 2 inches to one side. There is a tube inside the coulters that pours out liquid fertilizer , we call it pop up. The placement is so that the young seedling will get it very quickly. But we don’t put it right in the seed furrow so as not to burn the seedling with the strong fertilizer. This is the preferred 2 by 2  starter fertilizer placement for field corn. It usually is mostly Phosphorus with some Nitrogen. Phosphorus is important for young seedlings , especially with cool soils.

I remember my ABAC Soil Science professor, Mr. Sibbett, teaching us about this in his, sometimes crude way. “Plants have trouble taking up phosphorus when it is cool, conso…dam…quently, we need some phosphorus close to the seedling. There…dam… fore starter fertilizer is important.” They broke the mold after making him.


Here is this week’s question.

I was called out to identify a floating pond weed yesterday. Here are 2 photos, what is it?


_DSC3001 _DSC2991

Posted in Agriculture, Corn, Fertilization, Wildlife | Tagged: , | 4 Comments »

Fertilizer Spreader Evaluation

Posted by romeethredge on February 28, 2014

We are  spreading a lot of fertilizer in preparation for corn planting and its important to make sure you are getting a good pattern in the field.  Most newer spreaders calculate the rate per acre for you, in other words, you may know how many pounds of material you are putting out per acre.

But we are also concerned with the spread over the area. We want an even spread with no heavy or light streaks. This UGA publication at the link below covers how to evaluate your fertilizer spreader in detail. Also most spreaders come with a good guide to help with this process.

Last week we checked out this spreader with Brad Thompson and with a few adjustments it is spreading evenly and doing a good job. We put out containers to catch fertilizer behind the spreader and put grates in them to keep bouncing out down to a minimum and then later poured them into vials so that we could line them up and see if there were problems.

We also ran the next through to see how much fertilizer came from next door to the run we were measuring, overlap.


Here, below we see how much overlap we have.


Fertilizer flying out onto the field.





Empty the pan into vials according to location of the pan.



Checking out the levels in the vials to see how good our spread is.




Posted in Agriculture, Fertilization | Tagged: | Leave a Comment »

Fertilizing Wheat

Posted by romeethredge on November 15, 2013

Preplant Nitrogen fertilizer will depend mostly on what was just harvested from the field this season.  UGA Extension Grain Agronomist, Dr. Dewey Lee, says the amount of N we need depends on previous crop.  Below are recommended N amounts:

  • Cotton – 35 to 40 lbs/ac

  • Corn or Fallow – 30 to 35  lbs/ac

  • Soybeans – 15 to 20 lbs/ac

  •  Peanuts – 0 to 15 lbs/ac


Tillers produced in the fall generally produce the most grain per unit area. It is important not to over-fertilize with N in the fall as it may cause excessive growth and result in winter injury.

Total N will be between 100 and 130 lbs per acre.  We need most of it in late January and February as one or two sidedressings – depending on tillering.

Timing of N fertilization should be based on the pattern of uptake by the crop. Demand for N is relatively low in the fall but increases rapidly in the spring just prior to stem elongation. Therefore, make the fall applications of nitrogen at planting, and the remaining N prior to stem elongation. Use the lower rate of fall applied nitrogen at planting on heavier-textured soils and the higher rate on sandy soils.

Other nutrients should be applied according to a soil test preplant.

Since 65% of the total P uptake and 90% of the total K uptake occurs before the boot stage, these nutrients should be applied according to soil test before planting and thoroughly incorporated into the rooting zone.

The  2013-2014 UGA Wheat Production Guide accessed at this link:

Posted in Fertilization, Wheat | Tagged: , | Leave a Comment »

Bermudagrass Stem Maggot

Posted by romeethredge on October 11, 2013

Bermudagrass Stem Maggot is a new pest that has only been in the US for a few years. This is the first time I’ve been sure that I’ve seen it in deep southwest Georgia. This Alicia Bermuda pasture has stem maggot damage as well as Leaf Rust due to the leaching and use of potassium causing a deficiency that goes along with the leaf rust.  The Stem borer feeds into the stem and usually kills the top 2 or 3 leaves on the plant. There’s not a lot you can do about it but go ahead and make a cutting. there is ongoing research on insecticide sprays. You can go to a factsheet and a video by Dr. Dennis Hancock, UGA Forages Scientist,  concerning this problem by going to our UGA Forages site.

photo (7)

photo (7)-001

Posted in Entomology, Fertilization, Forages | Tagged: , | Leave a Comment »

Too Late For Landplaster?

Posted by romeethredge on August 8, 2013

A big fertility issue with peanuts this year that  was caused by the unusually wet weather is delayed gypsum/(landplaster)  applications.

Dr. Glen Harris, UGA Extension Soil Scientist, gives us the latest info concerning this.


  The recommended time to  apply gypsum is early bloom, which normally occurs around 45 days after  planting (or maybe as early as 30 days after planting).  Many peanut fields were simply too wet to  apply gypsum at this time.  How late is  too late to apply gypsum ?  Again, since  the “peak pod fill” period is 60 to 90 days after planting, and this is time  when developing are “sucking in” calcium dissolved in the soil solution  directly through the hull, once you get to 100 days after planting, it is  definitely too late to apply gypsum.   What about 60 days after planting ?   Well, 60 days after planting is better than 70 days after planting… which  is better than 80 days after planting (you get the idea).

Two other things to keep in mind if you are considering a  late (60-90 days after planting) gypsum application though are 1) will you do  more damage running over lapped vines than you gain by adding calcium?, and 2)  Did you really need a gypsum application in the first place?  Remember that if you had at least 500 lb/a of  soil test calcium in the pegging zone (top 3 to 4 inches of soil) AND a calcium  to potassium ratio in this soil sample of at least 3:1 or better, AND you are  not producing peanuts for seed….than you technically did not need a gypsum  application at all.  I hear about many  soil samples being in the 700, 800, 900 even 1000 lbs of Ca/a and with all the  rainfall we have had there should be plenty of soil water in the pore space to  dissolve the soil calcium and get it into the nuts.

Posted in Fertilization, Peanuts | Tagged: , | 2 Comments »

Question of the Week – Magnesium Deficiency

Posted by romeethredge on August 8, 2013

The answer to last week’s question is Magnesium deficiency. Muscadine grapes don’t need a tremendous amount of this nutrient but they do need some every year and so I recommend some Epsom salts, Magnesium sulfate, around every plant every year. Keeping your plants limed with dolomitic limestone helps as well.


Here’s the question of the week. What types of birds are these that I photographed here in Seminole County a couple of weeks ago at the edge of a pasture?


Posted in Fertilization, Wildlife | Tagged: | 2 Comments »

Sidedress Time on Cotton

Posted by romeethredge on June 12, 2013


Our oldest cotton is squaring now so it is time to start thinking about sidedressing fertilizer. Here’s some that was being sidedressed today.

The following is taken from Dr. Glen Harris, UGA Extension scientist’s, writings in the 2013 UGA Cotton Handbook. The total Nitrogen rate should always be applied in split applications. Apply 1/4 to 1/3 of the recommended N at planting and the remainder at sidedress. The preplant or at planting N application is critical for getting the crop off to a good start and ensuring adequate N nutrition prior to side-dressing.

Sidedress N between first square and first bloom depending on growth and color (toward first square if slow growing and pale green, toward first bloom if rapid growth and dark green). A portion of the sidedress N can also be applied as foliar treatments or through irrigation systems. No N should be soil-applied (either top dressed or through the pivot) after the 3rd week of bloom. Studies have shown that uptake of soil-applied N from by cotton roots is basically ineffective after this critical point.

Posted in Cotton, Fertilization | Tagged: , | Leave a Comment »

Corn Nutrient Problems

Posted by romeethredge on May 10, 2013

We have seen more corn nutrient problems than usual. There’s been Phosphorus deficiency, especially where pop up fertilizer wasn’t used. It is harder for the plants to take up in cool conditions. Also there’s been some Magnesium deficiency, with striped leaves and it’s sometimes a temporary striping condition when we get fast growth. Magnesium is more available to plants at higher pH’s. A plant tissue analysis is often needed to figure out these problems.

Then corn also needs Zinc, and we’ve seen a little Zinc deficiency in some fields. We don’t need much Zinc due to the fact that the plant doesn’t need much and because we may grow peanuts in the same field next year and they are sensitive to too much Zinc. Often growers can use a micronutrient pack in preplant fertilizer to suppply enough of the micronutrients. Zinc is more available to plants at lower pH levels. So overliming may actually cause Zn problems in corn.  I saw a case this week where they have new ground where they burned old trees and brush and they limed the field well and where these burn piles were, the Zinc deficiency problem is worse. We often get higher pH’s in ashy burn pile areas. A foliar spray or 2 of Zinc will often rectify the problem.





Posted in Agriculture, Corn, Fertilization | Tagged: , | Leave a Comment »


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