June Agronomy Newsletter

Richard L. Petcher

Regional Extension Agronomist for SWAL

Baldwin County Extension System

302A Byrne Street, Bay Minette, Al  36507

(251937-7176; Cell (251) 202-1009; SL 7*145

Email: petchrl@auburn..edu

                                                         Wheat Harvest

As of today wheat and oat harvest is just getting started.  A few growers started harvesting around May 19, but only on a few acres.  There are around 60,000 to 70,000 acres to be harvested in this area.  Growers have learned a lot this year about growing small grains.  Growers who have produced this crop for a long time are always improving on their information base for producing an even better crop next year.  Learning together with growers this year has been rewarding.  We have research tests at both the Brewton and the Fairhope Auburn University Research Stations.  We also have on farm research with an oat variety test on Walt and Rod Richardson’s Farm in Leroy and an on farm early wheat variety test with Ben and Matt Watson in Atmore and two more wheat variety tests with Hilbert and Eric Hall near Atmore.  We soon hope to harvest these tests plots.  We receive valuable information from these tests to pass on to growers.  Along with this we receive a wealth of information from growers across this region concerning their crop of wheat and oats and how they responded this year.  Hopefully by early July we will have the results compiled and have some excellent information for growers for next year.  Of primary importance is variety information for choosing your varieties for next year.  This will be very important for two reasons.  First, the variety you choose has 70 % of your success or failure in that one decision.  Second, it will be important to be able to order your seed early in order to obtain the varieties that you know will work on your farm. 

We have found Hessian flies in several counties, Baldwin, Mobile and Washington.  There may be Hessian flies in other counties, but I have not found any or talked with anyone who has.  We will study greatly on this before next planting season.  Two hundred Hessian fly eggs have been sent to The USDA Hessian fly research lab in Wisconsin to determine biotype. 

We hope to have several grower meetings in this area during July or August.  And we are also looking forward to compiling as much information as possible and sending to growers via e-mail and newsletters.    

Soybeans Hula Hoop Method of counting plant stand:  This method was given to me by Russell Hendrix, soybean grower in Fruitdale, Alabama.  This method may be of help to you. 

To count plants using a Hula Hoop, randomly toss the hoop and count plants inside the circle.  Convert plants per hoop to plants per acre by multiplying the number of plants by the appropriate factor.  “Most people prefer to use a 28 “ hoop for ease of calculation.  With a multiplication factor for that size at 19 plants x 10,000 = 190,000 population.

For a 26 “ hoop, multiply the number of beans by 11,800; for 30 “, by 8,900, 32”, by 7,800: 34 “, 6,900; 36 “, 6,200; and 38”, 5,500.  If you do not have a Hula-Hoop, use an 89 “ long wire or sprayer tubing to form a 28 “ inside-diameter circle. 

The Value of Wheat Straw:  Baled or Burned

Dr. Glen Harris, University of Georgia Soil Specialist

Two common options for dealing with wheat straw in double-cropping system are baling or burning.  Baled wheat straw, removed from the field, removes a considerable amount of nutrients.  The amount of nutrients contained in wheat straw from a 60 bu/a crop are estimated as follows:

With current fertilizer prices of 60 cents/lb of N, 50 cents/lb of P, and 35 cents/lb of K, this straw would have a value equivalent to$62/a.  Most of the value is split evenly between N and K.  Also, the value of Mg, S as well as micronutrients may add an additional dollar or two to the total.

A considerable amount of nutrients are also contained in the harvested wheat grain.  Approximately 72 lb N, 33 lb P, 20 lb K, 9 lb Mg and 4 lb S are removed for every 60 bu of grain.  While these removal figures are interesting and important to know, fertilizing crops based on removal figures is cautioned.  The reason why removal figures alone should not be used to guide fertilization is that even though a certain amount of nutrients are removed, the soil may still have the capacity to supply nutrients to the following crop.  The best way to determine if this supplying capacity is present is with a soil test.  Even in a wheat-soybean double-crop system, it is advisable to take a soil sample between the wheat and soybean crop.  This will assure adequate fertilization of the soybean crop, especially with K.  Notice that the amount of K removed in wheat straw is high.  Add to this that K is relatively mobile in soil, the cost of a soil test for guiding potassium fertilization of double crop beans alone is justified.

Burning wheat straw and residue before planting double-cropped beans is another practice sometimes used.  However, this practice is discouraged for a number of reasons.

First of all, burning wheat straw will still return P and K to the land in the form of ash, but nitrogen is lost in the process (it literally “goes up in smoke”).   Since N accounts for about half of the value of wheat straw nutrients, about $20/a are lost in this process, cutting the value from $60 to $40 per acre.

Another even more important reason not to burn wheat straw is that all of the carbon or organic matter associated with the straw will be lost.  Incorporating crop residues is one of the few ways to maintain the already low organic matter content of our Coastal Plain soils.  Granted, it is difficult to put an exact dollar figure on this organic matter.  However, it is commonly accepted that organic matter in soil will increase water holding capacity, nutrient holding capacity and overall productivity of a soil.

In conclusion, think abut the nutrients contained in wheat straw, know the dollar value, and keep the lighter in your pocket.

PEANUT FERTILITY

Calcium to Potassium Ratio:

The Calcium to Potassium Ratio should be a 3 to 1 ratio.  When there is too much K and not enough Ca the peanut shell actually absorbs K instead of the Ca. causing pops.

Peanut Pegging Zone Sample:  This is a well known practice in Georgia, but seldom practiced in Alabama.  I think growers would benefit by taking pegging zone samples especially on any field that might be in question for Calcium.  This should be done soon, before the peanuts begin to vine. The samples should be taken from the top two inches right in or near the row.  For most varieties, if you have 500 pounds of calcium in the pegging zone, there is no need for gypsum application.  For the larger seeded varieties such as AP-3 and Georgia 03L the Calcium levels should be near 1,000 pounds. 

Peanut Fungicide concerns for 2008: Bob Kemerait, University of Georgia Plant Pathologist

 According to representatives from the agrichemical industry, it is quite likely that growers will be faced with higher fungicide prices and reduced availability of fungicides this coming season. While there are a number of reasons for higher prices and reduced stocks, the bottom line for peanut growers is that they should begin planning NOW to ensure that they have the fungicides that they need to protect their crop. We recommend that growers take the steps early in the season to secure the fungicides that they will need for control of leaf spot and soilborne diseases.

Growers who use the Peanut Rx Index to determine the risk to disease in their fields may find that they can effectively reduce the number of fungicide applications without reducing the yield potential while at the same time increasing value. Growers who determine that their crop is a reduced risk because of good management may be able to increase the value of their crop by reducing labor, fuel, and fungicide costs. Growers can learn more about the 2008 Peanut Rx by consulting the 2008 Peanut Update or by talking to their county agent.

Provost Tank-Mix Restrictions: By Dr. Eric Prostko, University of Georgia Weed Scientest

In 2007, there were a few isolated problems with Provost tank-mixes that caused unexpected peanut injury (Figure 1).  In response to the concerns related to this issue, Bayer CropScience personnel evaluated more than 500 potential Provost tank-mix treatments.  Based upon their results, with input from UGA, the following tank-mix restrictions for Provost should be followed in 2008:

• Do not mix Provost with more than 1 other product (excluding compatibility agents).
• Do not use Provost in combination with adjuvants, surfactants, or EC pyrethroid insecticides (Mustang Max, Asana, Danitol, Karate, Baythroid XL, and Tombstone).
• Compatibility agents should be used when Provost is tank-mixed with the following products: Orthene, liquid boron, and liquid sulfur.  Tested compatibility agents include the following products: CoBlend, Complete Compatibility, Convert, and Latron AG-44M.

Stink bugs on Corn

As of today, the stink bug numbers seem to be increasing.  As wheat and oats are harvested the stink bugs often move into the corn crop.  Stink bug scouting on corn should begin when corn is in the seedling stage.  On young plants stink bugs feed on the base of the plant and injure the growing point.  Extreme feeding results in death of the plant.  If the growing point is badly damaged, the plant may develop multiple stems.    Moderate feeding results in a buggy whip symptom, where one side of the plant grows faster than the other and the tips of the leaves are entangled in the whorl.  Stink bugs do the most damage to corn when corn is in the early ear formation stage.  Most growers are not aware that this stage occurs two weeks before silking.  The little ear shoot is only ¾ inch long, and cannot be seen unless you pull back the leaf sheath.  Stink bug damage at this time will cause the ears to be aborted or severely deformed.  The ears will be C shaped or cow horned and are called banana ears.  Scout again during grain fill.  During silking and grain fill the stink bugs are affecting individual kernels.  If you want to protect the whole ear scouting must begin at early ear formation.  That is the time stink bugs do the most damage to corn.  The recommended threshold for treatment is when 1 out of 20 plants have stink bugs.  Pyrethroids work well on the green species, while organophospates work best on the brown.  Scouting for stink bugs can be difficult as they may be in one part of the field and not the other.  Fields bordering small grains or bordering pine plantations would be the most likely to have stink bugs.         

Management of Stored Grain

By: Warren Griffith REA – Agronomic Crops

                  Taking care of your stored grain can bring dividends down the road. Someone once said that your grain will only be as good as when you harvest it and that the quality can only get worse. This is true. That is why we must do everything we can to minimize our losses especially with our high grain prices.

                  First we start in the field by making sure the moisture level is where it should be. Extension pamphlet ANR-1126 IPM Tactics for On-Farm Stored Grain gives you step by step instructions for preparing for harvest. Small grains should be harvested at 11% if you have aeration in your storage bin. If you do not this needs to be lowered to 9%. Take moisture readings from several locations in the field to get an average. When you are ready to harvest, make sure you have all of your equipment thoroughly cleaned (combines, trucks, trailers, augers, grain bins etc.). Any of these can house starter colonies of insects. Make sure your bin is sealed thoroughly and apply an EPA-approved insecticide throughout the bin. Our stored grains IPM guide for 2008 will give you a list of approved insecticides to be used on the grain and in the bins.

                  As you harvest make sure your combine is set so you have as little damaged grain as possible and also as clean as possible. Damaged grain and organic matter when augered into a bin will buildup in the center. Less air flows through these “fines”. This increases mold growth and insect population which increases the temperature. This can be reduced by putting in good quality clean grain and flattening the crown in the bin when done. As you pour grain into the auger bin apply an EPA approved insecticide (Storcide II can be used on wheat but not corn or soybeans) check your 2008 IMP guide for stored grains.

                  Once your grain is in the bin you need to monitor it regularly. In the summer at least twice a month, in the winter once a month is sufficient. To monitor you can use inexpensive probe traps placed in five evenly spaced location in the top layer of grain. Leave these in one to five days or use a brass grain trier to sample. If numbers get too high based on the grade of grain you are shooting for (found in  ANR1126) then a fumigant will become necessary. A fumigant has to be used carefully and monitored. Extension pamphlet ANR-1154 Fumigating Agricultural Commodities with Phosphine is an excellent guide to lead you through using phosphine fumigants.

                  The cost of taking care of your grain is very little compared to what you save when selling a top quality grain. The difference in the price of food grade wheat and feed wheat is around three dollars a bushel. This can make a big difference even with just one thousand bushels.

                  If you have any questions or problems contact us and we will be glad to help you.

Again, I hope this information is helpful to you.

Sincerely,

Richard L. Petcher

Regional Extension Agent

Agronomic Crops

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