Seminole Crop E News

Agricultural News for Farmers and Agribusiness in SW Georgia

Posts Tagged ‘fertilization’

Question of the Week – Boron Toxicity

Posted by romeethredge on September 17, 2015

Peanuts need boron. If we don’t have enough we can see hollow heart and other problems. But we don’t need much. We need a half a pound of actual Boron per acre. A product like Solubor is 20% Boron so 2 foliar applications of 1.25 pounds of it will be all a peanut plant needs. If you use a liquid boron then do the math to make sure you get a total of a half pound of actual boron per season.

 Boron (B) is an essential micronutrient that is important to flowering, pollination, and fruiting of the peanut plant. We can get too much of it (maybe over double the recommended rate) however and cause some leaf symptoms like this. I’ve seen similar symptoms when a high rate of Basagran herbicide was applied.

 

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Here are some comments from UGA Scientist Glen Harris. “The standard UGA recommendation is 0.5 lb B/A, applied in two 0.25 lb/A foliar applications with early fungicide sprays. Single applications of 0.5 lb B/A can be used but include a greater risk of foliar burn. Since B leaches readily through sandy soils, foliar applications have always been considered the most effective and efficient application method.

Numerous B fertilizer materials are currently available. Most are either derived from boric acid or sodium borate and can be either in the liquid or wettable powder form. There are many “additives” used with these base B materials such as nitrogen and complexing agents designed to improve efficiency of uptake. However, extensive field testing over recent years has proven that all of the B fertilizers currently on the market are equally effective in terms of plant nutrition. Therefore, choice of B fertilizers should be made on price per pound of B. “

 

This week’s question is about this photo I took last week. A farmer showed me this on a very old farm. What are these 2 structures?

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Posted in Fertilization | Tagged: | 1 Comment »

Peanut Calcium

Posted by romeethredge on June 8, 2015

“The More Things Change…

The more they stay the same !” says Dr. Glen Harris, UGA Extension Soil Scientist, who gives us this report.  When we switched from growing small-seeded Georgia Green to large-seeded Georgia 06G we really thought we would need to increase our gypsum or calcium recommendations.  But after years of research we concluded that the recommendations didn’t need to change.

You can still use a pegging soil sample ( 3 inches deep, next to the peanut row soon after emergence) and if you have at least 500 lb/a of soil test calcium AND if your calcium to potassium ratio is 3:1 or better, than you don’t need to apply gypsum.  If you do not meet EITHER of these requirements then you need to apply 1000 lb/a gypsum at early bloom.  Also, all peanuts grown for seed should automatically receive this gypsum application regardless of soil test calcium levels.

There are a number  of different gypsum or landplaster fertilizers currently available. Chemically they are all calcium sulfate and the good news is that we have tested these too and they are all comparable as far as providing calcium to the pegging zone of a peanut.  Probably the most commonly one used now is technically called Flue Gas Desulfurized or FGD gypsum and is a byproduct of scrbbing sulfur gas out of smokestacks at coal burning power plants.  I call this “smokestack” gypsum although a lot of growers refer to it as “synethetic” gypsum.  There is also the old ‘wet bulk” phosphogypsum(a by-product of the phosphorous fertilizer production) and the naturally mined USG 500 among others.

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The lime method can also be used to provide calcium to the pegging zone of peanut but a few things : 1) this method should really only be used when you also need a soil pH adjustment, otherwise use gypsum if you need calcium, 2) both dolomitic or calcitic lime can be used.  Some people think you HAVE to use calcitic but this is not true, (dolomitic gives you Magnesium as well) and 3) the lime method does not work as well as gypsum under dryland conditions during years of normal rainfall.  We have good replicated field data to support this too.

We have also been testing putting calcium chloride though the pivot at peak pod fill (60-90 days after planting).  This method has a fit when you are on the borderline of needing some calcium. The benefits are you can apply this yourself and you do not have to run over the vines.  One disadvantage compared to gypsum or lime is that this method with not build your soil test calcium levels basically at all.”

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Wheat Sidedress?

Posted by romeethredge on January 26, 2015

 We don’t want to over-fertilize wheat with N in the fall when wheat is planted as it may cause excessive growth and result in winter injury.  We need most of it in late January and February as one or two sidedressings – depending on tillering. Total N will be between 100 and 130 lbs per acre. 

 

 When we plant wheat we don’t plant enough seed for each plant to just make one head. We want several heads from each plant. This time of year the plants are tillering or growing these multiple stems so that we’ll have more grain heads per plant in the field. Tillers — grain heads– kernels–  yield.

 

Last week I did some tiller counts and we are behind in many fields, so we need to split our sidedressing.  Often the wheat  rows are 7.5 inches wide so we measure 19 inches down the row to get a square foot and count total tillers in that area. Once we know the average number of tillers per square foot we can make some decisions about wheat sidedressing.  We want close to 100 tillers per square foot and if we are below that we generally go ahead with half our fertilizer sidedressing the last week in January and the rest the second week of February.

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In this photo you can see there are 3 tillers on this plant.

If we have 100 or so tillers per square foot and good growth and don’t see much yellowing of the older foliage, we can wait until the 2nd week of February to put out all of our sidedress fertilizer.

 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 before stem elongation. Therefore, make the fall applications of nitrogen at planting, and the remaining N prior to stem elongation. Use a 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

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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.

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Posted in Corn, Fertilization | Tagged: , | 2 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.

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Here is this week’s question.

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

 

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

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

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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:  http://www.caes.uga.edu/commodities/fieldcrops/gagrains/documents/2013-14WheatProductionGuide.pdf

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Sidedress Time on Cotton

Posted by romeethredge on June 12, 2013

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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.

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Corn Straightening Out

Posted by romeethredge on April 18, 2013

Corn is finally straightening out.  We’ve had some good weather right here recently. Some corn we checked today is in the V5 stage and is getting tall. Weeds are growing well too and palmer amaranth is emerging. Lots of corn sidedressing is going on and some fields that haven’t had it are looking somewhat deficient.  Weed controls are going out as well when the wind permits. _DSC4843

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Wheat Condition Good – Ahead of Schedule

Posted by romeethredge on March 4, 2013

Wheat is really moving along.

I looked at many fields today and all are jointing and many have some flag leaves out. I even saw a couple of heads trying to show themselves. I didn’t find any Stripe Rust, thankfully. There is still plenty of powdery mildew out there, and if it climbs to within a couple of leaves of the flag leaf, we may have to spray an early fungicide. We usually like to delay fungicide applications until the heads are out to get disease control on them as well as the flag leaf.

I’m not too worried about recent leaching rains on the fertilizer except for on deep sandy soils where some may need some additional fertilizer if it was done right before the rains, but each situation needs to be carefully considered and some tissue testing may need to be done.  Fertility looks good in fields I was in today to the point where there was some slight lodging where the fertilizer truck turned around near the edges. These were not sandy fields.

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Slight lodging(falling) where fertilizer truck turned around and put a little extra.

Slight lodging(falling) where fertilizer truck turned around and put a little extra.

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

Dolomitic Lime has Magnesium

Posted by romeethredge on December 21, 2012

We’ve had some discussions lately about liming and liming materials. Sometimes Hi Cal (Calcitic ) Lime has been used at times as a calcium source for peanuts before planting and it works pretty well and it also raises pH. We don’t want pH too high however, we start getting over 6.7 and we begin seeing some induced problems with things like Manganese (Mn) deficiency.

Dr. Glen Harris, UGA Extension Soil Fertility Scientist, has the following to say about liming and changing soil pH.

Dolomitic lime (that has 6 % or more Mg) is still the most common liming material used in

Georgia and provides magnesium (Mg) as well as calcium (Ca) and a pH adjustment.

Calcitic lime (less than 6% Mg) is becoming more popular and may be used in cases where high

soil Mg levels occur, it has been used as a calcium source in peanuts preplant.

If calcitic Lime is used for consecutive years, soil test Mg levels should be tracked closely with soil testing.

As soon as soil test Mg levels start to drop out of the high range into the medium range, the use of dolomitic lime should be resumed. The reason for this is that dolomitic lime is the most economical source of Mg fertilizer.photo (7)

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