ACES Baldwin County Office

Richard L. Petcher
Regional Extension Agronomist for SWAL.
Baldwin County Extension Office
302A Byrne Street, Bay Minette, AL 36507
(251) 847-2295, cell (251) 202-1009, SL 7*145
E-mail petchrl@auburn.edu

As of today February 23, 2007 the soil temperature in Washington County at 7:00 a.m. at 2 inch soil depth is 50 degrees. Soil temperatures are warming and it will soon be time to plant corn. The recommended soil temperature for planting corn is when the soil temperature at 7:00 a.m. at the 2 inch depth is 55 degrees for 3 to 5 consecutive days and the forecast is favorable for growing corn.

One of the wisest decisions you can make on your farm is to soil test. Money put in your pocket by not over applying or under applying fertilizer will pay for your investment in time and soil test your fields. Auburn University now has an on line system for you as a grower to receive your soil test reports.

Nutrient Recommendations for

Cotton

Phosphorus	Potassium
	Very high	High	Medium	Low	Very low
	Pounds N-P2O5-K2O per acre
Very high	90-0-0	90-0-0	90-0-60	90-0-90	90-0-120
High	90-0-0	90-0-0	90-0-60	90-0-90	90-0-120
Medium	90-60-0	90-60-0	90-60-60	90-60-90	90-60-120
Low	90-100-0	90-100-0	90-100-60	90-100-90	90-100-120
Very low	90-120-0	90-120-0	90-120-60	90-120-90	90-120-120

Cotton growers know there is a tremendous amount of money to be saved by cutting back on seeding rates. There is also some money to be made on a good crop of cotton. Having a good plant stand is essential in cotton production. Seed with associated technology and treatments have become extremely expensive. So take some time and thought to your seeding rate seriously. Seeding rate also depends on weather, soil temperature and soil moisture, seedling vigor, seed germ and the possibility of seedling disease. A final plant population of 35,000 plants per acre is about perfect here. The range can vary as cotton is fairly forgiving. But going very far either way can hurt you. There are 43,560 square feet in one acre. On a 36 inch row spacing you divide the square feet in an acre by 3. That gives you 14,520 linear or row feet you are planting. Two seed every foot gives you only 29,040 seed per acre. That is low and probably would lower your yield. Two seed every 10 inches gives you 34,848 seed per acre. That is 2.4 seed per row foot. With an 86% germination and plant stand you would have about 30,000 plants per acre. This is basically the industry standard for the low end of the planting rate. Three seeds every 15 inches also delivers 2.4 seed per row foot. Most varieties are now sold by the count of 230,000 to 250,000 seeds per bag instead of a 50 lb. bag. If you are planting on a 2.4 seed per row foot, one bag would plant 7.17 acres. In one University of Georgia tests conducted in South Georgia three years in a row the 3.1 seed per row foot was the highest end of the seeding scale and gave very little profit over the 2.8 seed per row foot. The most profitable range is from 2.4 to 2.8 seeds per row foot. At the 2.8 seeding rate one 250,000 count bag plants about 6.15 acres. A grower planting 500 acres would use 70 bags on the 2.4 seeding rate and 81 bags on the 2.8 seeding rate. Getting a good stand is critical to cotton production. You might want to use a higher seeding rate planting early or during adverse conditions and then lower your seeding rate a little later. When in doubt it is usually best to plant under circumstances conducive to good stand establishment (if possible) or use a slightly higher seeding rate.

Timing and fertilizing of cotton are very important. Not all soils are alike, nor all farmers equipment alike. Neither does the weather always cooperate. However, understanding your soil, how these nutrients work and your crops needs can very well help you in making three bale cotton. Taking a soil sample of each field is the only way to be accurate. It also can save you a ton of money from either over fertilizing or under fertilizing. Fertilizer is expensive. However, nutrition for your plants should never be the limiting factor. Many of our producers are capable of producing 3-bale yields. And fertilizing for 2-bale and 3-bale cotton is really quite similar. It just involves doing a lot of things well and having a really good growing season.

Liming: Most Alabama soils are naturally acidic. And cotton is sensitive to acid soil. Soil pH for cotton should range from 5.8 to 6.6. Do not attempt to grow cotton using reduced tillage practices unless the soil has been limed to a depth of 8 inches. Liming in the fall is the best as lime is slow to react in the soil. Next best is prior to planting.

Total nutrient removal by a 3-bale cotton crop is around 95 lb. nitrogen (N), 38 lb. P2O5, 47 lb. K20, 8 lb. sulfur (S) and 11 lb. magnesium (Mg). However, it may take more nutrients than this to make the crop depending on the soils ability to supply those nutrients. Only by soil testing can you know exactly what your soil has. Some of these nutrients leach from the soil and leach at different rates. The cotton also needs different amounts for different stages of growth. These units are given just as a guide. Many other factors such as the crop prior to planting, irrigation, drought or heavy rainfalls affect your fertility program.

Plant Nutrition: Early in the season concentrations of nitrogen (N), phosphorus (P) potassium (K) and sulfur (S) are very important to the young cotton plants. However, because the plants are small and their root systems are small they do not take up large amounts. Sulfur is very important at this time. Maximum uptake of N, P and K are between 60 and 80 days after planting. This growth stage is from first bloom to the end of peak bloom. This takes about three weeks. Make very sure you have these nutrients available before the plants need them.

Nitrogen- This nutrient leaches readily when applied in most fertilizer forms. Thirty to forty pounds per acre should be applied pre-plant and the remainder side-dressed before or at early bloom. Research has shown that regardless of how much N you apply after early bloom there is no increase in yield. Too much N results in excessive growth, late maturity, boll rot, increased insect problems, poor defoliation, and reduced fiber quality. Growth regulators (for example Pix) have helped growers control excessive growth, but managing N fertilization remains the most effective method in controlling excessive growth and producing optimum yields.

Phosphorus- is a primary plant nutrient that performs many functions in the cotton plant. It is slow to leach and is usually at a medium and often a high level in most fields that have been in production for a long time. Phosphorus is easy to manage simply by following soil test recommendations. Extension Alabama research has shown that once soil test P reaches a “high” soil test level, no additional P fertilization is needed for maximum yields. However, some growers who don’t feel comfortable apply a little anyway. This does not hurt anything as long as the grower can afford it.

Potassium: uptake is most rapid during the short period when bolls are maturing. Potassium in the leaves begins to move to the maturing boll where K accumulates in the burs. Potassium performs other roles in the cotton plant, but it is essential for the development of large bolls with strong fiber. This means that more K is needed late season during July and August. Potassium availability is closely related to soil moisture. During drought periods the roots in the deep subsoil obtain moisture and K. If the subsoil is low in K, the plants will exhibit K deficiency. K deficiency is displayed as premature yellowing of leaf edges in mid August. Severe K deficiency will cause premature defoliation of the crop and deformed bolls that do not open properly. K deficiencies are often found in cotton fields planted behind pastures and hayfields. When planting behind pastures and the soil tests low or medium for K apply 30 to 60 lb. K2O per acre above the normally recommended rate. Potassium is best applied pre-plant broadcast and incorporated. Side-dressing with additional K may be necessary on deep sands or when you are irrigating or have excessive rains.

Calcium (Ca)- Most of the Calcium for cotton is supplied by the lime when applied to keep the soil pH at the proper level.

Magnesium (Mg)- is an essential component of plant chlorophyll and is important to photosynthesis. A good liming program will generally supply adequate Mg for cotton, especially if dolomitic lime is used. One ton of dolomitic lime contains at least 120 pounds of Mg. Magnesium can be added in mixed fertilizers as (magnesium sulfate, magnesium oxide, potassium magnesium sulfate, etc)

Sulfur (S)- like N is an essential component of plant protein. Sulfur deficiencies show up as yellowing very similar to N deficiencies. It shows up early in the season when plant roots are small. Once these roots hit the subsoil they get plenty of S unless you are planting on deep sands or soils with a root restricting hardpan. Sulfur like nitrogen leaches so readily it is difficult to accurately soil test for S. At least 10 pounds per acre of should be applied annually to ensure your cotton is getting enough S early on. On deep sands you would want 30 pounds S per acre. This should be applied pre-plant or in the starter fertilizers.

Much research has been conducted with cotton and micronutrients in Alabama. The results show that cotton does not respond to any of the micronutrients except boron (B).

Boron (B)- is needed in protein synthesis and is associated with the cellular activity that promotes maturity along with increased flower set, more bolls and higher yields. However, the total crop uptake of B during the entire season is only 0.05 pounds B per acre. The plants greatest need for B is late in the season during boll set and maturity. Deficiencies are not dramatic and occur on sandy soils. Tests at 21 locations in Alabama showed about a 50 pound increase of seed cotton per acre by applying B. Boron can be applied with the pre-plant fertilizers, starter fertilizers, herbicide applications or more timely as a foliar spray with insecticide applications. Apply 0.3 pounds of B per acre.

Pre-plant fertilizers: Where the soil tests medium or high in P or K or both, a broadcast application is just as effective as band applications.

Side-dressing: Nitrogen leaches readily so it should be applied pre-plant and side-dressed at or before first bloom. Potassium may also need to be side-dressed on the sandiest soils. It is slower to leach, but may leach on deep sands, under irrigation or during heavy rainfall periods.

Poultry litter- is an excellent source of N, P and K. Two tons of broiler litter per acre will typically give you 90-120-90 pounds of N-P205-K20 respectively. However, only about 2/3 of the poultry nitrogen is available the first year, so it may be necessary to apply some additional fertilizer N.

Foliar Applications- may be useful to a grower in adding N to a crop during peak N uptake during blooming and boll set.

This article is a brief summary to be used as a guide. Soil testing and closely scouting your fields is very important to cotton plant nutrient management. For more information go to Publication ANR 0619 Cotton Fertilization Management in Alabama.

Three-Year Yield of Dry Land Peanut Varieties at the Wiregrass Research and Extension Center, Headland, Alabama 2004-2006

This research is conducted by Dr. Jim Bostick with the Alabama Crop Improvement Association and Brian Gamble and Larry Wells with the Alabama Experiment Station in Headland, Alabama.

Three-Year Yield of Dry Land Peanut Varieties at the Gulf Coast Research and Experiment Station in Fairhope, Alabama.

This research is being conducted by Dr. Austin Hagan, H.L. Campbell, J. Ron Weeks, Auburn University Peanut Team and Malcolm Pegues and Ronny McDanield with the Gulf Coast Research and Experiment Station in Fairhope, Alabama.

This information should soon be on line under Timely Information Auburn University web site.

Weed resistance is a major problem for farmers in many areas of the world now. The website www.weedscience.org/in.asp lists over 300 plants that have confirmed herbicide resistant biotypes (a type of the same species that, while looking normal, has changed in some fashion from the original). This website lists invasive weeds by country and by state. Alabama has three confirmed herbicide resistant species including common cocklebur resistant to the organic arsenical herbicides (MSMA, etc.), goose-grass resistant to the dinitro-aniline herbicides (trifluralin, Prowl, etc.), and annual bluegrass resistant to the triazine herbicides (simazine, atrazine, etc.). We probably have glyphosate resistant horseweed in north Alabama, although this has not been confirmed yet by testing. Why should we be concerned about this in Alabama, and what if anything can we do to prevent or delay the development of herbicide weed resistance?

Farmers and all those involved in agriculture should be greatly concerned about the development of herbicide resistant weeds. Although not much is made of the impact that modern weed control methods have made on American and world agriculture, the fact remains that herbicides account for the lion’s share of pesticides used in row crop agriculture. Our system is based on production “without” hand labor to control weeds in all major crops. These crops in Alabama include cotton, peanuts, corn, and soybeans; as well as small grains, commercial vegetables, and small fruit and tree fruits. Today, one cotton farmer can use reduced tillage and Roundup Ready technology to produce a crop that would have taken several workers and much more machinery just 15 years ago. If glyphosate resistant pigweed becomes a problem in our fields, this production system will become less feasible, with a probable increase in weed control costs.

Most weed researchers and specialists believe there are four or five major points in delaying the onset of weed resistance in our fields. Delay is the term we should be using since we have already failed at preventing the development of herbicide resistant weeds.

1. First, don’t bring in resistant weed seed into clean fields, check and clean used equipment.

4. Use higher labeled rates of foliar herbicides and spray smaller emerged weeds (timely spraying).

5. Finally, take no prisoners (kill all escaped weeds, don’t allow them to make seed).

Roundup Ready varieties (and the use of glyphosate) make up the majority of acres planted to cotton and soybean. Roundup Ready corn may see a similar increase in the acres planted in the state over the next couple of years. Peanuts growers still use conventional herbicide technology for weed control, but some of the herbicides used in peanuts have documented weed resistance. Cadre, Strongarm, Staple, Envoke, Classic, Scepter, Pursuit, Accent, and Beacon all belong to the ALS inhibitor category (amino acid disruptors). These herbicides have traditionally been very effective on pigweed species. Now several weeds including pigweed biotypes have shown resistance to the ALS inhibitors. Working other herbicides into the weed control program will help delay the onset of pigweed (and other weed species) resistance. A dinitro-aniline herbicide (Prowl, trifluralin, etc.) should be soil-applied in broadleaf crops to provide residual control of pigweed and annual grasses. Metolachlor (Dual Magnum, etc.), Harness/Surpass, or Outlook should be used soil-applied in corn for pigweed and annual grass control. Metolachlor can also be used in peanuts and soybeans soil-applied, and tank-mixed early postemergence with glyphosate in Roundup Ready cotton. Intrro and Outlook can be used in soybean with similar pigweed activity as metolachlor. Older preemergence herbicides like fluometuron (Cotoran, etc.) in cotton and simazine (Princep, etc.) in corn should be applied behind the planter. Valor can be used pre-emergence in peanuts and post-directed in cotton to manage pigweed resistance. Older, foliar-active herbicides like 2,4-D, 2,4-DB, Clarity, Ultra Blazer, Basagran, Storm, Cobra, and Reflex, as well as newer products like Aim should be incorporated into the weed management system of the appropriately labeled crop to provide different modes of action on emerged pigweed. Liberty-Link cotton technology using Ignite herbicide also provides a different mode of action on pigweed. Ignite is a broad-spectrum foliar herbicide similar to glyphosate, but works on a different mode of action and therefore has activity on glyphosate resistant pigweed.

The success of any weed management program depends on proper weed identification and timely spraying. Make sure you know what species are problems in your fields and select the right herbicide for this weed. Plan on using more than one herbicide in the program; each with a different mode of action. Soil-applied products are valuable in delaying the onset of weed resistance, and are imperative in managing resistant pigweed already confirmed in our fields. Post-emergence treatments should be applied to small weeds at the proper labeled rate. Don’t let weeds get too big and hope a foliar herbicide will kill them. A combination of soil-applied and early post-emergence sprays are absolutely necessary in managing weeds. This will hopefully provide a height difference between the crop and weeds. Several very effective post-directed herbicide mixtures are available in cotton, corn, and soybeans that will provide excellent control of emerged weeds. Staying ahead of the weeds is always better than playing catch up. Cotton Incorporated has recently printed a four page handout, “Managing Herbicide Resistance in Cotton Cropping Systems”, that contains good information. Copies of this handout may be obtained from Cotton Incorporated, 6399 Weston Parkway, Cary, NC. 27513, or online at www.cottoninc.com.

This time of year it is best to scout your small grain fields as often as possible for insects and disease. Aphids could be a problem, and already have been in some oat fields. The threshold for aphids on wheat plants 6 to 10 inches tall is 6 aphids per foot of row, at stem elongation stage it is 2 aphids per stem, at boot/flag leaf stage it is 5 aphids per stem and at head emergence it is 10 aphids per head. You will want to scout for Hessian flies. Planting late and planting resistant varieties are the answer. Biotype L Hessian fly was found in Baldwin County a few years ago. The only wheat variety showing some resistance to this Hessian fly strain is Pioneer 26R61. Hessian fly scouting this year will be for preparation for next years wheat variety decisions. Other insects to scout for are Armyworms, Cereal Leaf Beetles, Chinch Bugs, Lesser Cornstalk Borer and Grasshoppers.

The weather so far has been wet and cold. If the weather stays wet and warms up growers especially need to scout for diseases. Powdery Mildew, Septoria and Leaf Rust will most likely take off in the next few weeks. Yellow Striped Rust has started in Louisiana. It is on the wheat variety AGS 2000. It has been a problem in Georgia and Mississippi several of the past few years. So far it has not been much of a problem in Alabama. However, be on the look out.