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Agronomy notes
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Permanent Link: http://ufdc.ufl.edu/UF00066352/00149
 Material Information
Title: Agronomy notes
Uniform Title: Agronomy notes (Gainesville, Fl.)
Physical Description: v. : ill. ; 28 cm.
Language: English
Creator: Florida Cooperative Extension Service
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida.
Place of Publication: Gainesville
Publication Date: July 2012
 Subjects
Subjects / Keywords: Crops and soils -- Florida   ( lcsh )
Crop yields -- Florida   ( lcsh )
Agriculture -- Florida   ( lcsh )
Agronomy -- Florida   ( lcsh )
Genre: serial   ( sobekcm )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
periodical   ( marcgt )
 Notes
Additional Physical Form: Also available to subscribers via the World Wide Web.
Additional Physical Form: Electronic reproduction of copy from George A. Smathers Libraries, University of Florida also available.
General Note: Description based on: January 1971; title from caption.
Statement of Responsibility: Florida Cooperative Extension Service, University of Florida, Institute of Food and Agricultural Sciences.
 Record Information
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000956365
notis - AER9014
System ID: UF00066352:00149

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Agronomy Notes July 2012 Volume 36:7 Features: Forage: Summer precautions for legume seeding in the fall ........Page 2 Agronomy Notes is prepared by: Ken Quesenberry, Interim Chair and Y. Newman, Extension Forage Specialist (ycnew@ufl.edu); J. Ferrell, Extension Weed Specialist (jferrel@ufl.edu); F. Fishel, Pesticide Information Director (weeddr@ufl.edu); Calvin Odero, Weed Specialist ( dcodero@ufl.edu); D. Wright, Extension Agronomist (wright@ufl.edu.. The use of trade names does not constitute a guarantee or warrant of products named and does not signify approval to the exclusion of similar products. The Institute of Food and Agricultural Scienc es (IFAS) is an Equal Employment Opportuni ty-Affirmative Action Employer authorized to provide research, educational information and other services only to indi viduals and institutions that function without regard to race, color, sex, age, handicap or national origin. For information on obtaining other extensi on publications, contact your coun ty Cooperative Extension Office Florida Cooperative Extension Service/Institute of Food and Agricultural Sciences /University of Florida/Millie Ferrer-Chancy, Interim Dean. Miscellaneous: Weeds and Pesticides: Gramoxone SL compatibility......................................Page 3 Atrazine litigation settlement...................................Page 4 Rice herbicides for the Everglades Agricultural Area .Page 5 Calendar of events.....................................................Page 5 Upcoming IFAS CEU Day on August 21 .............Page 4 Crops: Cotton boll set............................................................Page 2 Soybean planted after corn harvest..............................Page 2

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4 2 Cotton boll set With recent rains, cotton can set bolls quickly during bloom (usually July and August). Bolls normally set during stress free periods. Most stress is from dry weather but insects and dise ase can also be a problem. With good moisture going into early bloom the majority of the cotton yi eld can be set during the first 3 weeks of bloom. It is important that insects and other pests are controlled during this period so that the early bolls are set early making for an early harvest since we are going into an El Ni no weather phase which can mean a wet harvest season and fewer days to harvest. Soybeans planted after corn harvest With soybean prices remaining at near record highs ma ny corn growers are considering planting soybeans as soon as harvest is finished. Soybeans can yield 20-40 bu/A under good conditions but should be planted as early as possible with the cutoff date being the first week of Augus t with later plantings usually yielding less due to maturing under cooler conditions. Beans can be drilled with 2-4 seed per foot of row or planted in wide rows with 8-9 seed per foot of row. Additional K may be needed on very sandy soils along with S and minor elements. Always inoculate soybean seed if it has been more th an two years since soybeans were in the field. Crops Dr. David Wright, Extension Agronomist North Florida REC, Quincy wright@ufl.edu Summer Precautions for Legume seeding in the Fall Legume planting either on prepared see dbed or sodseeding has several advantag es. Legumes if in association with grasses are usually used to i) increase yield per acre, ii) to improve the quality of the forage on offer, iii) to fix nitrogen into the soil, or iv) to improve the seasonal distribution of a pasture. Adding clovers or cool-season grasses allows quality feed during winter an d early spring when pastures would then be dormant and without active growth. If planting legumes in the fall a couple of precautions need to be taken in the summer. One of them is to check the soil pH and apply lime if needed to raise the pH. Ma ny legumes will require pH ar ound 6.0. This slightly higher pH is needed for the rhizobium bacteria, involved in N fi xation, to survive. Liming should be done a few months in advance. The first step is to properly collect a soil sample from the area to be limed. Samples are normally taken to a depth of 4 inches. The soil sample should be sent to a soil testing laboratory fo r determination of pH and lime requirements. If lime is needed it should be applied as soon possible since lime reacts with soil that it comes in contact but the effect on the soil pH below the top inch or so requires longer time of interaction. Therefore, lime should be applied 3 months prior to planting A second precaution if controlling weeds in the summer is to use herbicides with no residual activity. Many herbicides will have residual activ ity in the soil that will pe rsist for several months and keep your legume seed from germinating. Please check with your weed specialist for herbicide use in the summer that will not affect your legume (broadleaf) germination in the fall. Forages Dr. Yoana Newman, Extension Forage Specialist ycnew @ufl.edu

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4 3 Gramoxone SL compatibility We have recently been observing unusual problems a ssociated with the Gramoxone SL formulation. We are seeing a black oily residue in the tank as well as some herbicide incompatibility. The full explanation for this is not yet available, but we ha ve learned a few things. Black slime. The black slimy materi al in the tank usually occurs when Gramoxone SL is mixed with an 80:20 surfactant. It is believed that the gl ycol in the surfactant is coming out of solution and is turning black due to the dye in the Gramoxone SL formulation. This material is cl ogging strainers and sticking to the inside of the spray tank. Cleaning these clogged strainers has been difficult. Ammonia nor acid will remove the slime. About all we have found that works is to remove the strainers and wash them with al cohol. If the slime dries inside the tank, I am not sure if it can be removed. However, this black material is not bei ng observed when mixing with surfactants containing 90% activ e ingredient (or higher). Compatibility. Others are seeing problems with mixing Gramoxone SL and Reflex. It is believed that these herbicides can be mixed without issue if a compatibilit y agent is added to the tank prior to loading the herbicides. Other herbicides have also been implicated with non-compatibility when mixed with Gramoxone SL, but at this point it is difficult to determine which are actually problematic. There have also been reports of he rbicide injury that mimics paraqua t burn occurring weeks after Gramoxone SL was applied particularly when spraying clethodim and crop oil. To date, we have not been able to determine why this is occurring. However, we do recommend that clethodim be applied with a maximum of 1 pt of crop oil per acre and that amm onium sulfate be kept to less than 8 lb per 100 gal. These reduced crop oil and ammonium sulfate rates will not reduce the grass control that you can expect from clethodim. If you observe any Gramoxone SL mixing issues, call your local County Extension Office so we can better understand all the cause of these problems. Weed Science Dr. Jason Ferrell, Extension Weed Specialist Email: jferrell@ufl.edu

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4 4 Atrazine ligation settlement Syngenta has reached an agreement in principle to sett le the lawsuits filed by community water systems in Illinois state and federal courts. The settlement agreement was filed with the federal court in Illinois May 24. It is expected that the pending state litigation in Illinois will be stayed pending final approval of the settlement by the federal court. The settlement is considered material to the company, a nd until it is filed w ith the Court, the existence of the agreement and its terms are strictly c onfidential. As soon as the proposed se ttlement is filed with the Court, Syngenta and the plaintiffs attorneys will issue a joint news release using language negotiated as part of the agreement. Syngenta acknowledges no liab ility. And, despite almost eight years of litigation, the water systems involved were never able to come up with any new scientific studies relating to the sa fety of atrazine. Under the terms of the agreement, a total of $105 million, le ss the costs of notice and administrati ve expenses of the settlement and plaintiffs counsels fees, will be paid to the participating water systems accordi ng to an allocation formula approved by the Court as part of th e Settlement Agreement. The minimum payment to water systems that are eligible to partic ipate will be $5,000. For a period of 10 years after final Court approval (i ncluding any appeals) of the settlement or July 1, 2014, whichever is earlier, Syngenta, its subsidiaries, customers, partners, retailers, distributors and related entities will be released by the water systems from liability related to the presence of atrazine in their water, except for pointsource contamination. Applicators and users may still be liable to community water systems during this time for any damages caused by off-label use. Water systems will have approximately 90 days from the tim e the Court grants preliminary approval to object or opt out of the settlement. A fairness hearing to grant final approval of the se ttlement is expected approximately 60 days after the time for objecting or opting out closes. In addition to the water syst ems named in the litigation, any community water system that has ever detected any level of atrazine in its water is eligible to join the class of plaintiffs that will share in the settlement. Systems th at have never detected atrazine in their water may also test during the approximately 90-day notice period, following preliminar y approval of the settlement by the Court. Under the terms of the agreement, if more than 10 percent (by claim va lue, as a proportion of the fund) of eligible water systems with claims arising within 10 years preceding the date of the Settlement Agreement opt out of the settlement, Syngenta has the option of terminating the settlement. Pesticides Dr. Fred Fishel, Pesticide Information Director weeddr @ufl.edu Upcoming IFAS CEU Day on August 21 Dear Colleagues: astatewide Polycom event toearn upto6pesticide applicator CEUs isplanned for Tuesday, August 21(9:00 a.m. EDT 4:00 p.m. EDT). Please contact Dr. Fishel for additional information.

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Above: Cold damage on sugarcane. Photos by D. Calvin Odero 5 Weed Science Dr. Calvin Odero, Extension Weed Specialist dcodero @ufl.edu Rice herbicides for the Everglades Agricultural Area Stam 4E (propanil) in combination with Sandea/Prof ine (halosulfuron), Basagran (bentazon), or Londax (bensulfuron) have been the foundation of postemergence herbicide weed cont rol programs in drill-seeded rice in the Everglades Agricultural Area (EAA). Other herbicid es including Clincher (cyhalo fop), Grasp (penoxsulam), Grasp Xtra (cyhalofop plus triclopyr), and RebelEX (penoxsulam plus cyhalofop) registered for use in Florida can be integrated into weed control programs in the EAA. Clincher is a postemergence herbicide for control of a wide spectrum of annual and seedling perennial grasses, such as barnyardgrass, fall panicum and junglerice. It o ffers wide application window (from early pre-flood to late post-flood), no rotational restrictions, excellent crop safety, and flexible application timing. Clincher can be applied up to 4-leaf rice to post-flood at 13.5 to 15 fluid ounces/acre plus 1 quart/acre of crop oil concentrate by ground or air. Grasp is a low-use-rate herbicide for control of barnyardgrass, many broadleaf and annual sedge weeds. Important benefits of Clincher include excelle nt pre-flood weed control, up to 3 we eks residual weed control under moist conditions, wider application window (e mergence to 60 days before harvest) and crop rotation flexibility. Grasp can be applied at 2 fluid ounces/acre plus 1 quart/acre crop oil concentrate from rice emergence to 60 days prior to harvest by ground or air. Grasp Xtra and RebelEX herbicides deliver broad-spectrum control targeting grasses, broadleaf and annual sedge weeds. Grasp Xtra can be applied to ri ce from 2to 3-leaf to half-inch inte rnode elongation stage of rice at 16 to 22 fluid ounces/acre depending on weed and the stage of weed development by ground or air. RebelEX can be applied at 16 to 20 fluid ounces/acre to drill-seeded rice at emergence to 60 days before harvest by ground or air. These herbicides provide rice grower s in the EAA with additional modes of action to control problematic weeds such as barnyardgrass, fall panicu m, sprangletop, and annual sedges. To follow the link, press Ctrl and put cursor over link, and click. July 21 Perennial Peanut Producers Field Day, Beef Research Unit, Gainesville, FL http://perennialpeanutfieldday2012.eventbrite.com/ Jul y 27-29 Florida Small Farms Conference, Kissimee, FL http://smallfarms.ifas.ufl.edu/ Oct 16-18 Sunbelt Ag Expo, Moultrie, GA http://sunbeltexpo.com/ Oct 21-24 American Society of Agronomy, Crop Science Society of America and Soil Science Society of America Annual Meeting, Cincinnati, OH https://www.acsmeetings.org/ Calendar of Events