COTTON AT CRITICAL GROWTH STAGE

    Last week I hosted a Cotton Workshop that focused on the phase of cotton growth from first square to first bloom, the current stage of our cotton crop.  Since this growth stage is so important, I thought I would review some basic cotton physiology as it relates to current growing conditions.
    Here are some important pointers to consider when managing cotton during this growing stage.  Currently the heat units for our cotton crop are very near normal and early planted cotton is at least at the six to seven node stage and setting squares. This cotton should be at first bloom by the first week of June.  As a general rule, for every 50 heat units accumulated, the cotton plant will produce a new node.  Moreover, at this time the cotton plant is continuing to develop an extensive root system and will do so until about one week after flowering.
    It is important to note that up to 85% of the lint yield will be determined by first bloom, and up to 80% of that yield will come from the first fruiting positions on the cotton plant.  So now is the time to see that our cotton has optimum growing conditions and we need to protect that first fruiting position.
    Cotton insects during this growth stage that warrant serious considerations are cotton fleahoppers at which the treatment threshold is 15 per 100 terminals. In addition, aphids can also be a problem, and if more than 50 aphids per leaf persist for more than seven days then treatment for them is probably warranted.
    One of the goals during this growing stage should also be to develop the best plant structure possible.  To achieve that, we need to consider the growth potential of the plant.  Ultimately the, final cotton plant height here in the Coastal Bend should be 30 to 35 inches for 30-inch rows, or a  rule-of-thumb used to predict optimum plant height is to multiply the row width times 1.1.  With these limits, one can ensure that row middles are covered but not to such a degree that boll rot will develop.
    The cotton plant produces a new node in the terminal every three days. Each new internode continues to extend and thicken over the next 12 to 15 days, depending on temperature and growing conditions. The most rapid expansion (85 percent) occurs in the first six to 10 days. The arrival of heavy rains or use of irrigation will cause cotton to increase nitrogen uptake which can  result in rapid growth.
A cotton plant will do a good job of regulating its own height if there is a lack of  heavy rainfall and the presence of a heavy fruit load during this time period.
    To help control rapid growth the product Mepiquat chloride (MC) is used. MC will help retard excessive plant height as it suppresses stem elongation of newly formed internodes.  The minimum MC concentration in the plant necessary to provide a maximum level of reduction is 12-15 ppm.  It is extremely important to make the first applications of MC early enough, usually around  Matchhead Square to keep the plant’s growth under control.  For more information about using MC to manage cotton plant height consult the publication found at this web site; http://safiles.tamu.edu/agronomy/cotton/b6042.pdf
    So at the conclusion of this growth stage that is first bloom, one can count the nodes above white flower (NAWF) to determine just how well the crop is doing.  In fact, we would like to see that number around eight or nine nodes.  If that number is at five, the cotton plant is in trouble and production of additional squares will end as this is known as “cut out.”  If the plant has nine NAWF at first bloom, this is an indicator that the plant has a lot of “horse power” and great yield potential. So lets all hope that around June 10 our cotton plants have eight or nine NAWF, and of course a little more rain between now and then will help achieve that goal.

HAY QUALITY INFLUENCED BY SEVERAL FACTORS

With an early wet Spring, there have been several people able to make hay in the last few weeks which brings me to today’s topic,  factors that influence hay quality.  Hay varies in quality more than any other harvested feed crop. Hay quality can vary widely, even when composed of one and the same species, when grown in the same vicinity, and when grown and cured under similar conditions.   Moreover, hay can look good, i.e., dark green color, and still be low in quality, or can look bad, that is not have a good dark green color, and still be good quality.  The best way to determine what quality you have is to have it tested by a forage testing lab.
    Factors that determine hay quality include stages of maturity at harvest, soil fertility, nutritional status of the plant, available moisture during the growing season, season of the year, ratio of leaves to stems and stem size, weed control, foreign matter, harvesting, weather at harvest and storage. Of all the factors that influence quality, stage of maturity or age of the plant at harvest is the most important.  In fact, about 70% of the quality of hay is determined by stage of maturity at harvest. As a plant matures toward heading, flowering and seed formation, the growth pattern changes from leaf production to hard stem formation.
    Since leaves are more digestible than stems and contain most of the nutrients, the higher the leaf content, the higher the quality.  The younger the plant, the greater the proportion of leaves, thus a higher quality plant.  A quick visual method to determine maturity can be done by looking for seed heads. As a simple guide, grass hays with only a few immature seed heads is high quality, and as the number and amount of mature seed in the heads increase, the quality decreases.
    Soil fertility is also an important factor in determining the ultimate quality of hay.  Nitrogen fertility rates for grasses greatly influence the crude protein levels in forages harvested at the right stage of maturity.  The nitrogen content of a forage is a direct measure of its protein content. The nitrogen that is extracted from a forage is multiplied by a factor of 6.25 and reported as percent crude protein. Thus, a forage containing 2 percent nitrogen contains 12.50 percent crude protein.  Phosphorus, potassium and other nutrients are also critical to maintaining stands and producing quality hay. A soil test should be taken once a year to determine the amount of plant nutrients remaining after the previous years productions to replace those elements removed by harvest.
    So when is the best time to make hay?  The proper stage of growth for harvesting forages is the time when the greatest amount of total digestible nutrients per acre may be obtained. This usually represents the best compromise between quality and yield.  Generally, the younger the crop at the time of harvest, the higher the quality but the lower the yield. The more mature the crop at time of harvest, the higher the yield but the lower the quality.  Research also indicates that forages are higher in quality during spring and fall and lower in quality during mid-summer.
Recent experiments (USDA) indicate that cattle prefer afternoon cut hay over morning cut hay. Since cells make sugars and carbohydrates in the presence of sunlight, afternoon cut hay may contain a higher percentage of highly digestible sugars and carbohydrates. Plants cut in the morning have partially depleted the supply while respiring or using energy through the night.
    Color is not always a good indicator of quality, as it usually is a good indicator of the curing process following cutting.  A bright green hay usually means the hay was cut at a desirable stage of maturity and cured rapidly.  The yellow color that is often seen, is a sign that there was a significant amount of sun bleaching, but quality is not seriously reduced.  A brown colored hay usually indicates that excessive moisture fell on the hay during the curing process, and usually has a musty odor.  Odor can also be an indicator of reduced quality.  Hays with off odors like mildew, mustiness or rotten odors can be an indicator of reduced quality and poor acceptance by livestock.
    Another factor that can impact hay quality is the presence of foreign matter.  Yes, weeds are the biggest problem, and sometimes even injurious materials like threeawn grass seedheads, sandburs, and toxic plants can be found.  When buying hay, you should always look for foreign matter. Finally, soft, pliable hays are usually more palatable than hard, firm hays, as this usually indicates the lack of lignin or stem maturity.  
    The goal of harvesting should be to maintain the highest nutritive quality as possible through cutting at the proper stage of maturity, promoting rapid drydown, maintaining high leaf content and timely baling at the right moisture content.  Bacteria and fungi that cause hay to deteriorate, need moisture to grow. If hay is baled at a too high moisture, bale heating occurs shortly after harvest. Microbes are not able to reproduce if moisture levels are below about 14%.
Small 60-70 pound bales can be baled at 16-18% moisture while hay stored in large round bales
needs to be dryer (14-16%) at baling since moisture is unable to escape from the center of a large bale.

COTTON WORKSHOP TO FOCUS ON FIRST SQUARE TO BLOOM

    Some of our early planted cotton will be producing the first square very soon and thus enter a growing stage that is of critical importance as yield potential is being determined.  This time of development for the cotton plant is critical, as by the time the cotton plant begins to bloom, 80 to 90% of crop to be harvested is on the plant.
    Currently our cotton crop is growing through a stage of development in which the roots grow faster than the plant parts above ground.  A young taproot may extend 6 inches into the soil by the time the first true leaf is visible.  Then soon after the first true leaf appears, the roots begin developing an extensive lateral system.  Roots grow where moisture, oxygen and temperature are optimum. As these three factors decline, root growth slows and, as a consequence, the plant takes up less water and nutrients.  This would explain why recent very wet conditions in some parts of the county, actually stressed the young cotton plants, as too much water starved the plant of oxygen.
    Before the reproductive stage is reached in the cotton plant, the primary insect pests of cotton are the thrips complex and the aphid complex.  Recent research has shown that cotton is extremely susceptible to thrips damage before squaring. By the time producers notice damage (crinkled leaves, leaf margins curling upwards), the economic damage has been done.
    In general, weed control is critical during the first 6 weeks of the season.  Although having a few weeds in a field generally has little effect on production and harvesting, having many weeds can cause severe problems.  Research has shown that if weed competition ends at 4 weeks, little yield is lost, however beyond that 4 week time frame, competition from weeds begin to reduce cotton yields.
    To address critical management issues during this time of crop development, the Gulf Coast Cotton Management Workshop will be held on Wednesday, May 12, 2010 with the focus on “First Square to First Bloom.”   The workshop will be held at the Texas AgriLife Research and Extension Center at 10345, State Hwy 44, just west of the Corpus Christi Airport.
    Registration will begin at 8:00 a.m. followed by the program at 8:30 a.m and will conclude by 11:30 a.m.  Workshop topics and speakers will include the following; Overview and Current Crop Conditions by Dr. Juan Landivar, Resident Director of the Research Center, Physiology of Cotton Plant by Dr. Carlos Fernandez, AgriLife Research Scientist, Managing Fertility, Plant Height, and Square Retention, by Dr. Dan Fromme, Extension Agronomist, Insect Management by Dr’s Roy Parker, Extension Entomologist and Mike Brewer, AgriLife Research Entomologist, and Using Computer Online Tools to Help Manage Crop by Jeffrey Stapper, County Extension Agent - Nueces County, and Carlos Fernandez.
    Participants in the workshop will be awarded CEU’s toward their Pesticide Applicator and Certified Crop Advisor Licences.  This workshop is one of a series that will be held throughout the growing season this year. The workshop is being sponsored by the Texas AgriLife Extension Service and Texas AgriLife Research.  More details are available from the Nueces County Extension Office at 361-767-5223.
Educational programs of the Texas AgriLife Extension Service are open to all people without regard to race, color, sex, disability, religion, age, or national origin.  Individuals with disabilities, who require an auxiliary aid, service or accommodation in order to participate in any of the mentioned activities, are encouraged to contact the County Extension Office eight days before all programs for assistance.

GRAIN SORGHUM SHOWING NUTRIENT DEFICIENCIES

    The rains we received last week were both beneficial and detrimental, depending on wether you received 1-inch or 3-inches plus your neighbors runoff from out west.  Fields along some of our major creeks, like Petronila Creek were under water for several days, thus drowning or severely stressing crops from super saturated conditions.  Our recent warm temperatures have helped move along our degree day units, if fact for grain sorghum and corn we are back up to about 93% of normal, while our cotton degree day units are about 98% of normal.  Our wheat crop continues to develop well with some reports of rice stink bug damage occurring on grain that was in the milk to soft dough stage.
    Our grain sorghum crop growth stages range from just a few leaves to reaching the stage of growth at which time many things begin to happen with the plant. For the older sorghum plants, the total number of leaves has been determined and the grain head size is being determined at this time.  Now is also the time that rapid nutrient uptake is occurring and yes we are seeing some nutrient deficiencies.  These nutrient deficiencies tend to be more obvious in situations with adequate soil moisture, when the plant is growing rapidly, and in many cases has a small root system, so it can not capture all of the nutrients that it needs.  Until grain sorghum develops an extensive root  system, young plants may not be able to obtain enough ferrous iron to maintain normal growth on some soils. Although iron is not a part of the chlorophyll molecule, it is required to supply enough chlorophyll to support the growth of new leaf tissue.
    High-pH, calcareous soils not only reduce the availability of soluble iron in the soil; they also change the soil’s cation-exchange capacity so that less iron is present and available for exchange overall. The result is a more slowly growing plant and subsequent uneven flowering dates. This not only delays ripening of grain and harvest , but the uneven pollination undermines an effective insecticide spray program for controlling sorghum midge.
    Mild chlorosis ranges from a lighter green leaf color that progresses to increasing interveinal striping, to almost no visual symptoms.  Moderate chlorosis is seen where sorghum plants are yellow or yellow-green in strips, or irregularly  shaped areas of the field. Fields may have intermittent blotches of chlorotic plants scattered in a salt-and-pepper (random) arrangement. Iron chlorosis is often sporadic throughout the field, or it may be associated with some land-moving event.
    Visual symptoms are often the best indicator of whether or not to treat chlorotic fields or parts of fields for iron chlorosis.  Applying iron as a foliar spray is effective in restoring the green color and they are most effective when repeated at 10-day to two-week intervals. Several products are available for field use to correct iron chlorosis.  Iron sprays require a spreader-sticker or detergent in order to be effective. If a commercial spreadersticker is not available, ordinary household detergent may be used at rates of 1/4 to ½ pint per 50 gallons of solution. Thorough coverage and wetting of the entire leaf surface is necessary for good results. Avoid too much detergent to minimize the chances of leaf burn.

WET WEATHER PROMOTES FUNGI IN WHEAT

The week of cloudy, wet weather has promoted conditions in our wheat fields that is ideal for the growth of Black Head Molds or Sooty Head Molds.  Yesterday, I and Dr. Ron Duncan, Small Grains Specialist with Texas AgriLife Extension Service were examining wheat fields around the county and we found this fungi, giving heads a dirty or sooty appearance, called Sooty Head Mold.  These fungi are considered to be a saprophytic or possibly weak or opportunistic parasites, but they can accelerate senescence and many contribute to kernel smudge.
Control measures are rarely justified.  During harvest, clouds of dark spores are common in fields in which this fungi is present.

Another Grassbur Control Option Available

Pastora herbicide (nicosulfuron + metsulfuron) has received a Section 18 Emergency Exemption label for use in bermudagrass pastures and hay meadows for control of sandbur (grassbur) through June 30, 2010.  At this point, the product can only be applied to control grassbur, so this weed must be present at the site.  Pastora is effective for controlling grassbur up to 1.5 inches tall, so timeliness of the application is very important, requiring a conscious scouting of the field for emergence.  Pastora must be applied to bermudagrass that is less than 4 inches tall to insure adequate interception of the herbicide by the grassbur plants.  As always, be sure to read and follow the label directions.

WHEAT AND OILSEED FIELD TOUR SET

    Despite very wet conditions this past fall and winter that prevented some folks from getting their wheat planted, there will be some wheat made this year in Nueces County.  A Spring Wheat Variety Trial was established on January 12, 2010 at the Texas AgriLife Research and Extension Center in Corpus Christi, Texas.  In addition,  Cool-Season Oilseed Crops were also planted to evaluate their potential in the Coastal Bend of Texas.
    To show these crops potential, a Field Tour has been scheduled for Thursday, April 15, 2010 at the Texas AgriLife Research and Extension Center on HWY 44, just west of the Corpus Christi Airport.   The Field Tour will begin with registration at 8:30 a.m. followed by the program at 9:00 a.m.  An indoor session will focus on current Wheat and Oilseed Markets, Wheat Production Update, Cool Season Oilseed Options, Sunflower Best Management Practices, and Guar Production Potential.  The program will then move outside to tour the variety trials which will conclude by 11:45 a.m.   The variety trials consist of; 11 spring wheat, 7 safflower, 7 camelina, 13 canola, and 9 flax. Participants in the program will be awarded 2 CEU’s. This program is being sponsored by the Texas AgriLife Extension Service of Nueces County and the local Agricultural Advisory Committee.
Individuals with disabilities, who require an auxiliary aid, service or accommodation in order to participate in any of the mentioned activities, are encouraged to contact the County Extension Office eight days before all programs for assistance. Extension programs serve people of all ages regardless of socioeconomic level, race, color, sex, religion, disability or national origin.