February 3, 2007

Wheat

What is the number one question being asked? Does this wheat have a chance of making grain? It was an impressive site to see all the wheat that emerged after the snow melted off. The wheat that is just now emerging will have several challenges before it will have grain to harvest.

1. Late maturity: Late emerged wheat will mature later subjecting the wheat to higher temperatures and drought stress during grain fill. Disease organisms will usually be present at higher levels during the latter part of the growing season, causing more risk to the maturing crop from wheat leaf rust and/or stem rust.

2. Poor Root System Development: Seedlings which emerge in December and January have a weak, shallow root system. The root system will not have the potential for moisture and nutrient uptake that wheat planted in the optimum time frame would. Hot, dry conditions at flowering and during grain fill would result in a significant yield reduction.

3. Tiller numbers: Wheat grows very slowly at low temperatures and is essentially dormant below 40 degrees. Late emergence dates subjects the wheat to cooler temperatures which results in very few tillers being produced.

4. Phosphorus inefficiency: Phosphorus availability is low in cold soils. P moves by diffusion from the soil solution to the root surface, and diffusion rates are inversely related to soil temperature. Root system expansion is slower in cold soils which results in lower phosphorus uptake by the plant. Phosphorus is an important nutrient in the development of the root system and ultimately a healthy plant.

5. Vernalization: Winter wheat undergoes two important physiological changes in the fall. The processes that bring about these changes are known as vernalization and cold acclimation. Vernalization is required before heading will take place in the spring. If seeding takes place after the optimum date, vernalization will be affected and maturity delayed. Cold acclimation is necessary before plants can survive the low temperatures of winter. Vernalization and cold acclimation require growth when minimum morning and maximum afternoon soil temperatures are below 45 and 50°F, respectively. Winter wheats require a number of chilling hours to stimulate the formation of reproductive growth. These chilling hours are usually considered those above freezing but below the temperature at which wheat growth goes dormant from the cold (between 40 and 32 degrees). Wheat varieties vary somewhat with respect to vernalization requirements. Late planting reduces vernalization on wheats, which may be significant, particularly in southern growing areas of District 7. Optimum planting dates for wheat grown for grain production in our area is between October 15 and November 15. Yield reductions can be expected when wheat emergence occurs after November 20, however, weather conditions will be a major influence to the extent of the reduction.

6. Reduced Plant Vigor: Four to five weeks growth at temperatures higher than those required for vernalization and cold acclimation is necessary to ensure that plants have sufficient energy reserves available for a quick start in the spring. Seeding when maximum afternoon soil temperature is approximately 64°F usually allows sufficient time for this growth and development to take place. Seeding later, when temperatures were lower, resulted in delayed germination, slow plant emergence and a reduced rate of subsequent plant growth. This usually translates into a higher risk of winterkill, lower yield and delayed maturity.

Wheat producers should consider making a fertilizer application as soon as soil temperatures increase. Between February 15 and March 15 the wheat will reach a stage of growth where nutrients and water uptake will increase significantly. If producers intend to get the most from the dollars invested on fertilizer they need to apply nutrients soon. Soil nutrient levels will need to be at a high level when the formation of the head occurs (shortly before rapid spring growth begins). If the head can be found above the soil surface the producer has lost the opportunity to impact the number of spikelets per head and the number of seeds per spikelet.

In some wheat fields, Wild oats are just now reaching the three-leaf growth stage. At this stage, the Wild oat plants can still be controlled with several herbicides that are available. The three weed control products that don't have a grazing restriction are Puma, Finesse Grass and Broadleaf and Osprey. We should have at least two weeks remaining for the application of these herbicides to control Wild Oats. It will be important that the following conditions exist to get the best possible control using Puma: 1) check the weather forecast and make sure that night time temperatures will be above 40 degrees for two days prior and following the application, and 2) have adequate soil moisture at the time of application. Preferably, producers will apply the herbicide using 20 gallons of water per acre. If the opportunity occurs in February, I will be trying to establish a Wild Oat control test. We will just have to wait and see.

Cotton

For your information there will be a cotton production conference held at San Angelo on March 21, 2007. There are a number of specialists from across the state involved in this activity. The information provided at this meeting will be useful to the agents in cotton producing counties.

As you know the way we design and conduct cotton variety tests has changed. I still attempt to include the varieties that the producer wants and varieties that perform well in their county. However, there are many new varieties being introduced to the market in 2007. Our main thrust is to eliminate varieties that do not perform before they make it into large scale production. To do this we have to put varieties into a wide range of tests. We are serving our producers well if we can identify what genetically superior lines are available and what their growth and development traits are. Contact me soon and let's design your 2007 Result Demonstrations.

Linked is the production data from cotton variety tests conducted in 2006. With the hot dry year we had in 2006 the fiber length and strength in most tests was very impressive. You can tell by the notes that several final reports are still being developed. As soon as the information is available please send it to me. THANKS!

There are a lot of winter weeds growing on land that is to be planted to cotton this spring. The winter weeds are using valuable soil moisture that should be reserved for the cotton crop to be planted. Since we have more than 60 days before planting, several different herbicides can be considered. You need to determine what kind of weeds you have and make sure that they are listed on the herbicide label. The least expensive broadleaf control herbicide is 2,4-D and it will eliminate a wide range of weeds. If the maximum daytime air temperatures are cool then the Ester formulation should be used. If you are concerned about other weeds that may emerge prior to planting you may want to include a herbicide that is soil active for a short period of time. Special consideration should be given to the crop that is going to be planted; use only approved herbicides and rates. Tests were conducted in 2002 and 2003 on controlling winter weeds; the links to the studies are (http://sanangelo.tamu.edu/agronomy/newsltr/weed02a.htm) and (http://sanangelo.tamu.edu/agronomy/newsltr/weed05.htm). The herbicides listed in the last table in each report is linked to a picture of that treatment in the test.

Grain and Forage Sorghum

It is time to request Corn, Grain Sorghum and Forage Sorghum seed for 2007 result demonstrations. If you need additional information about the varieties and hybrids available, I have compiled a list of company web sites and the URL is: http://sanangelo.tamu.edu/agronomy/newsltr/company.htm. Companies need to be contacted in the near future to acquire the seed you need for testing.

Sesame

Pesticide Recertification Training

On Monday February 12, there will be a training conducted at Abilene for producers needing to obtain a Private Applicators License. For more details and to register for the meeting call Gary Bomar at (325) 672-6048.

There will be a meeting conducted February 8, starting in the afternoon at the Texas A&M Agricultural Research and Extension Center north of San Angelo, Texas. The educational meeting will be worth 5 CEUs for TDA license holders that complete the course requirements. For additional information contact the Tom Green County Extension office at (325) 659-6522.

There will be a meeting conducted during the Texas Farm and Ranch Wildlife Expo (Abilene, Texas) on February 20 & 21, 2007. There are several educational meeting being conduced where Texas Department of Agriculture CEUs are available. For additional information contact Gary Bomar at (325) 672-6048.

Don't forget that your TDA pesticide applicators license will expire the end of February. If you have not gotten your paperwork for renewal you may want to contact the TDA.

Monthly Calendar

February

February 1, Travis County, Texas and Oklahoma Physiology Study Group Meeting

February 1, Taylor County, Soil and Soil Fertility

February 5, District Office, Office Conference

February 6, Howard County, Plant Growth and Development

February 8, Callahan County, Multi-County Forage Production Meeting

February 8, Tom Green County, Multi-County Pesticide Training–Drift Minimization

February 15, El Paso County, Cotton and Pecan Workshop

February 20 & 21, Taylor County, Texas Farm and Ranch Wildlife Expo

February 22, Burnet County, Plant Growth and Development

March

March 5, District Office, Office Conference

March 14, Llano County, Plant Growth and Development

March 21, Tom Green County, Concho Valley Cotton Conference

March 21, Tom Green County, Southern Rolling Plains Cotton Growers Meeting

March 22, Brown County, Ag Day

March 29, Tom Green County, BioEnergy Training

	Sincerely, Billy E. Warrick, Ph.D. Professor and Extension Agronomist Texas Cooperative Extension Texas A&M University System