AG NEWS. May, ESTIMATING NITROGEN LOSSES FROM WET SOILS Lloyd W. Murdock Extension Soils Specialist, University of Kentucky

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1 AG NEWS May, 2016 Meade County Extension Service 1041 Old Ekron Road, Brandenburg, KY Fax ESTIMATING NITROGEN LOSSES FROM WET SOILS Lloyd W. Murdock Extension Soils Specialist, University of Kentucky Wet soils cause nitrogen losses, and determining how much nitrogen is lost is necessary to choose the proper management op ons. In cases where high intensity rain results in high runoff, leaching losses will probably be low. The primary nitrogen loss mechanism in saturated soils is denitrifica on, which occurs when soil nitrate nitrogen (NO 3 N) is converted to nitrogen gas by soil bacteria. Two to three days of soil satura on is required for bacteria to begin the denitrifica on process. Well drained upland soils that have been wet from a series of rains probably have not experienced much denitrifica on. Soils in lower landscape posi ons that stay saturated longer will likely lose more N. Losses can be calculated by es ma ng 3 to 4 percent loss of fer lizer NO 3 N for each day of satura on. Use the Table below to determine how much fer lizer NO 3 N was in the soil. Table 1. The amount of applied fer lizer that is in thenitrate nitrogen form 0, 3, and 6 weeks a er applica on Week A er Applica on N Source % Fer lizer as NO 3 N Anhydrous Ammonia (AA) AA with N Serve* Urea Urea with N Serve* UAN Ammonium Nitrate *Nitrifica on inhibitor that slows transforma on of ammonium to nitrate. Sincerely, Andy Mills Meade County Extension Agent for Agriculture & Natural Resources

2 ESTIMATING NITROGEN LOSSES FROM WET SOILS Con nued. EXAMPLE: Determining the Amount of N Loss A farmer applied 175 lb nitrogen (N)/A as urea to corn grown on poorly drained soil. Because of a series of heavy rains, three weeks a er applica on the field became saturated for seven days. How much N was lost? Step 1. Determine the amount of applied N that was in the nitrate (NO 3 N) form. According to the table, 50% of the urea will be in the NO 3 N form three weeks a er applica on. 175 lb N X 50% = 88 lb N. Step 2. Determine the amount of N lost. Remember that two days are needed for the bacteria to begin the denitrifica on process. Therefore, denitrifica on occurred for five days (seven days total satura on minus two days to start the process). With 4% lost each day for five days, 20% would have been lost. 88 lb N x 20% = 18 lb N lost and 157 lb N remaining. The N loss calculated in this example is not as high as most people would assume. A soil N test can verify this es ma on. Nitrogen Soil Test An addi onal tool for determining NO 3 N in the soil a er flooding is a NO 3 N test. The soil sample should be taken down to 12 inches deep, and several samples should be taken in each field of both the low and higher ground. The samples should be mixed well and a subsample sent for nitrate analysis. If the nitrate N is less than 11 ppm, there is a low amount of plant available N in the soil. Therefore, there is a good chance corn will respond to a sidedress applica on of N ranging from 100 to 150 lbs. N/acre. If the nitrate N is between 11 and 25 ppm, there is a greater amount of plant available N in the soil, indica ng corn may or may not respond to sidedress N. The recommended sidedress N applica on at this soil test level is 0 to 100 lbs N/ acre. If the soil test nitrate N is close to 11 ppm, then higher sidedress N rates would be used. Lower rates would be used as nitrate N approaches 25 ppm. The test is least accurate in this range, so the test results can only be used as a broad guide. If soil test nitrate N is greater than 25 ppm, there is adequate plant available N in the soil, which indicates corn will probably not respond to sidedress N applica on. Nitrogen Broadcast Prior to Rain Farmers some mes broadcast fer lizer nitrogen on a field within 24 hours of a heavy rain. In most cases, very li le nitrogen is lost to runoff, especially if the field was under no ll soil management. The nitrogen fer lizer begins to dissolve almost immediately a er being applied to the soil surface and will dissolve completely in a short period of me. As rain begins, the first water that falls moves into the soil, taking most of the fer lizer nitrogen with it. Once in the soil, most of the fer lizer nitrogen is protected from runoff. The only excep on is a very intense rain soon a er applica on that also erodes topsoil from sloping areas. Even in this situa on, the loss would probably be less than one third of the fer lizer applied. Asparagus Ham Quiche 1 pound fresh asparagus, trimmed and cut into 1/2 inch pieces 1 cup finely chopped ham 1 small finely chopped onion Preheat oven to 400 F. Place asparagus in a steamer over 1 inch of boiling 2 (8 inch) unbaked pie shells water and cover. Cook un l tender but s ll firm, about 4 6 minutes. Drain and 1 egg white, slightly beaten cool. Place ham and onion in a nons ck skillet and cook over medium heat 2 cups shredded reduced fat cheddar cheese un l lightly browned. Brush pie shells with beaten egg white. Spoon the ham, 4 large eggs onion and asparagus into pie shells, dividing evenly between the 2 shells. 1 container (5.3 ounces) plain Greek yogurt Sprinkle 1 cup shredded cheese over the mixture in each shell. In a separate 1/3 cup 1% milk bowl, beat together eggs, yogurt, milk, nutmeg, salt and pepper. Pour egg 1/4 teaspoon ground nutmeg mixture over the top of the cheese, dividing evenly between the 2 shells. 1/4 teaspoon salt Bake uncovered in a preheated oven un l firm minutes. Allow to 1/4 teaspoon pepper cool approximately 20 minutes before cu ng.

3 Insec cide Impregnated Ca le Ear Tags by Lee Townsend, Extension Entomologist University of Kentucky College of Agriculture Insecticide-impregnated cattle ear tags release small amounts of an insecticide which are distributed over the animal during grooming or rubbing. In general, ear tags have provided excellent, long term control of horn flies and a reduction in face fly numbers. Factors to consider when using these products: Read the label before you purchase and use insecticide ear tags. All tags are labeled for beef cattle while only those with certain active ingredients are approved for use on lactating dairy cattle. Check for any limitations for use, such as animal age. Look for the common name of the active ingredient (for example, permethrin). In some cases, different brands of tags contain the same active ingredient. You can save money by comparison shopping, or avoid inadvertently using the same active ingredient if resistance is a potential problem. Consider the recommended number of tags per head. Some brands are used at the rate of one per animal. University of Kentucky research trials have generally shown that systems which use two tags per animal seem to provide better face fly control than those which rely on a single tag. Animals only need to be handled one time to apply the tags. However, this is not necessarily when you would normally work your animals. For fly control, it is best to tag animals after horn fly numbers reach 50 or more per side. This reduces the chances of developing resistance to the active ingredients that are being used. Normally, tags provide 12 to 15 weeks of fly control. Tagging too early in the season can mean that the tags are not providing good control in the fall that will help to control the overwintering population. With insecticidal ear tags, the control system moves with the animals. This may be an advantage if animals are moved at intervals and dust bags or back rubbers are not in place in every pasture or grazing area. What areas of the animal are treated by ear tags? Research with insecticide ear tags fitted with a dye showed that the area immediately behind the ears and forward to under the eye and down to the back of the mouth are treated pretty thoroughly. No dye was transferred to the legs, back-line, belly or hips. There is additional spread of the insecticide as the animal grooms itself and mingles with other cattle. Why do ear tags tend to work better against horn flies than face flies? Differences in behavior between these two fly species is probably part of the story. Horn flies spend most of their time on the animal. They suck small amounts of blood frequently and leave only to lay their eggs on fresh cattle droppings. This constant presence on the animal means they are certain to come in contact with some of the insecticide and be killed. Face flies spend only a small amount of time on the animal. Usually, they are off resting on vegetation. They visit the face, primarily under the eyes and around the mouth. Insecticide residues may not last as long on these surfaces, or the fly may not remain on the treated area long enough to pick up a lethal dose. However, some of the newer synthetic pyrethroid insecticides are active against flies in such small quantities, that much better reduction in face flies is seen. What types of insecticide ear tags are available now? There are three main types based on the active ingredient (s) that they contain. Organophosphate (OP) insecticides such as diazinon, fenthion, pirimofos methyl, or a diazinon + chlorpyrifos combination. These tags provide good horn fly control and moderate face fly control. Synthetic pyrethroid (SP) insecticides- fenvalerate and permethrin are the original members of this group. These tags are sold under a variety of brand names. Usually they are less expensive than the new, more expensive synthetic pyrethroids, such as cyfluthrin, lambda-cyhalothrin, and zeta-cypermethrin. These tags provide good horn fly control and better face fly control than the OP tags. These two groups of tags contain insecticides that attack the nervous system of the fly in different ways. Seasonal rotation between an OP and an SP insecticide can be useful in combatting insecticide resistance that has developed in horn flies in some areas of Kentucky, USA. Resistance, indicated by a failure in horn fly control, can develop when tags containing the synthetic pyrethroid permethrin have been used for several consecutive seasons. No resistance to organophosphates, or the new synthetic pyrethroids, has been seen. A relatively new group of combination tags has appeared. These couple an OP and a SP in the same tag. Current examples pair lambda-cyhalothrin and pirimiphos methyl or cypermethrin and chlorpyrifos. The assumption is that the OP would control SPresistant horn flies. Tags need to be removed at the end of the fly season in the fall to reduce the potential for insecticide resistance in both lice and flies.

4 Insec cide Impregnated Ca le Ear Tags Con nued. Safety precautions associated with using insecticide ear tags Non-permeable gloves should be worn when tagging animals. Tags should not be handled bare-handed under any circumstances.the concentration of insecticide in the tags varies from 8% to 36%. The tags are manufactured so that the insecticide is rubbed off the surface and on to the animal. Any handling of the tags leaves some insecticide on the hands. The insecticide then can be transferred easily to the mouth, eyes, face or other areas of the body. Signal words on the label range from CAUTION to WARNING. Several products carry statements about the potential for allergic reaction following exposure. Many are easily absorbed through the skin or eyes, some have irritation vapors. Wear protective gloves and wash hands thoroughly with soap and water after tagging or when taking a break. CAUTION! Pesticide recommendations in this publication are registered for use in Kentucky, USA ONLY! The use of some products may not be legal in your state or country. Please check with your local county agent or regulatory official before using any pesticide mentioned in this publication. Of course, ALWAYS READ AND FOLLOW LABEL DIRECTIONS FOR SAFE USE OF ANY PESTICIDE! Set Disc Mowers Height to Prolong Grass Hay Stands Article From Forage News For more forage information, visit our UK Forage Extension Website at: Dr. Garry Lacefield and others conducted a survey of forage specialists across the U.S. a few years ago on the reasons orchardgrass hay fields seem to be thinning out in recent years. Survey respondents identified lower fertility, severe weather conditions, insects, and diseases as factors contributing to stand loss, but they felt that the number one reason for shorter stand life was low cutting heights. And low cutting heights were mainly attributable to disc mowers. Disc mowers are great hay cutting tools, with their ease of operation, speed of harvest, and ability to easily harvest thick stands. These mowers allow producers to easily harvest at 1 to 2 inches. Low cutting heights like this are fine for alfalfa since it regrows from energy stored below ground in it s large taproot, but can be disastrous for grasses like orchardgrass. Orchardgrass has a more upright growth habit and low cutting removes all the leaves needed for photosynthesis and the base of tillers (stems) where carbohydrates are stored for regrowth. An Asbury University student, Leah Saylor, conducted a research experiment on orchardgrass cutting height at UK 4 years ago. Leah found that just one season with low cutting heights significantly reduced stand longevity and increased weed infestation, regardless of the addition of fertilizer treatments. The results of Leah s experiment are shown below in Figures 2 and 4. These results show that the recommended cutting height of 3 to 4 inches for orchardgrass and similar grasses is essential to maintain thick, weed free stands. Most disc mower manufacturers sell skid shoes to insure higher cutting heights. These are well worth the price.

5 Rainy Season Equals Phytophthora Disease By Nicole Ward Gauthier, Extension Specialist and Kim Leonberger, Extension Associate Spring rains can create growing condi ons that are devasta ng to most landscape plants. Wet soils are favored by a group of pathogens called water molds, or oomycetes, which cause a range of root and stem diseases. Water molds are found in most soils, but plant stress and high pathogen numbers can lead to severe disease. One common water mold is Phytophthora. This pathogen is common in Kentucky and has recently been diagnosed causing root rot on numerous plants, such as blueberry, arborvitae, and Colorado blue spruce. Phytophthora Facts Symptoms vary greatly due to disease severity and host characteris cs. Roots are concealed, so disease o en goes undetected un l plants begin to decline or upper plant parts wilt (Figure 1) as a result root reduc on (Figure 2). Disease o en begins during rainy spring weather, but it is typically not no ced un l hot dry weather ini ates wil ng. Aboveground infec ons may result in symptoms ranging from yellow mo ling of leaves to water soaked lesions on leaves or succulent stems. Woody ssues may develop cankers, o en near the soil line. Free water is required to allow for swimming spores to move to new sites of infec on. Spores are spread by splashing water and movement of contaminated soil par cles. The pathogen can produce survival structures that allow it to lie dormant during hot dry seasons or during winter. Figure 1: Lower por ons of the plant may decline or die back as a result of Phytophthora root rot. Note excess water puddling. (Photo: Nicole Ward Figure 2: Phytophthora root rot results in root reduc on. (Photo: William M. Brown Jr., Bugwood.org Management Most Phytophthora diseases can be prevented or managed using cultural prac ces. Consider the management ps below to prevent infec ons or to help manage infected nursery or landscape plants. Improve drainage through management of surface water, limited irriga on, diver ng downspouts, or plan ng in raised beds. Disinfest tools and containers. Dispose of infested po ng media. Inspect plants prior to purchase or during produc on to insure that plants are healthy prior to installa on. Do not compost infected plant material. Remove plant debris and other sources of inoculum. Mulch plants to reduce spore splash. Use resistant cul vars whenever possible. Phytophthora spp. are not true fungi, so not all fungicides will be effec ve against these pathogens. Fungicides must be specifically labeled for oomycetes. Homeowners can u lize fungicides containing phosphorus acid to protect plants from infec on or suppress disease development. Commercial produc on fungicides include products containing cyazofamid, etridiazole, mefenoxam, or phosphorus acids. For addi onal informa on on fungicide use, please contact a local UK Coopera ve Extension Service agent. Always follow label direc ons when u lizing fungicides. Resources Fungicides for Management of Diseases in Commercial Greenhouse Ornamentals (PPFS GH 03) Fungicides for Management of Landscape Woody Ornamental Diseases (PPFS OR W 14) Homeowner s Guide to Fungicides (PPFS GEN 07) Landscape Sanita on (PPFS GEN 04) Rela ve Effec veness of Various chemicals for Disease Control of Ornamental Plants (PPFS GEN 13)

6 Cooperative Extension Service University of Kentucky Meade County 1041 Old Ekron Rd. Brandenburg, KY NONPROFIT ORG US POSTAGE PAID BRANDENBURG, KY PERMIT 49 RETURN SERVICE REQUESTED The Great Pumpkin Pursuit September 17, 2016 If you are trying to grow a giant pumpkin or watermelon for the weigh off compeon, here are some more growing ps. Prize Money : Biggest Pumpkin & Biggest Watermelon Observe plants for diseases. Our recent weather has not been favorable for most garden crops, especially watermelons. Damping off is a common disease that thrives in cool, wet condi ons. Try to prevent soils from staying wet all the me. This disease a acks the roots and stem from the soil surface and below. Other diseases such as gummy stem blight, bacterial wilt, and different leaf spots may show up as the plants begin to vine. Fungicides containing fix copper, chlorothalonil, as well as mancozeb can help in preven ng these diseases. Watch for fruit set. As female blooms develop, just let one grow and remove the others in order to grow the biggest possible melon or pumpkin. The female blooms are the ones with the miniature melon or pumpkin at the base of the flower. The other blooms are males and do not need to be removed. Weed control is essen al. Weeds harbor insects, rob nutrients, as well as create a desirable environment for diseases. Good Luck! If you have any ques ons or concerns, give me a call at (270)