There s no way to predict what will happen after these dates, but at least producers have a little more time this year.

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1 Number 73 March 16, Spring planting of Roundup Ready and conventional alfalfa 1 2. Full-rate and reduced-rate residual herbicide programs for corn 3 3. Canola research and field tours 6 4. Are liquid fertilizers better than dry fertilizers? 7 1. Spring planting of Roundup Ready and conventional alfalfa Producers who want to plant Roundup Ready alfalfa this spring will have to hurry. On March 12, a U.S. District Court issued a preliminary injunction order that allows continued harvest, use and sale of Roundup Ready alfalfa, but placed limits on the purchase and planting of seed until further hearings are held. Growers who intend to plant Roundup Ready alfalfa and have already purchased the seed as of March 12 may do so if said seed is planted by March 30, The order also said growers intending to plant alfalfa after March 30, 2007, must plant non-genetically engineered alfalfa and that sales of Roundup Ready alfalfa seed are prohibited after March 12 pending the court s decision on permanent injunctive relief. There s no way to predict what will happen after these dates, but at least producers have a little more time this year. Planting alfalfa in March is unusual in Kansas, but shouldn t cause any problems. Although most alfalfa is planted in the fall in Kansas, spring is also a good time for planting. Fall-seeded alfalfa will usually produce more first-year tonnage than springseeded alfalfa, but planting in April usually results in more reliable moisture conditions and less risk of poor stand establishment. Before planting alfalfa, producers should be sure to have the soil tested for ph, phosphorus (P), and potassium (K). There is still time to get this done before a spring planting, and the results will pay off for the life of the stand usually five to seven years.

2 Alfalfa does best when the soil ph ranges from 6.5 to 7.5. If the soil ph is less than 6.5, production will be reduced. At very low ph levels, the stand may be thin and weedy. Applying lime, if needed, before planting alfalfa will pay big dividends. Alfalfa is a big user of P. For every ton of alfalfa removed from a field, 10 pounds of P are removed. Past research in Kansas has shown that applying and incorporating P fertilizer, if recommended by a soil test analysis, results in large increases in productivity. In a no-till situation, P fertilizer can be surface-applied and still have a long-term beneficial effect on yields. It s best to plant alfalfa no-till or reduced-till, if possible. Minimizing tillage can decrease planting costs and help maintain soil moisture levels. Alfalfa can be successfully no-tilled into wheat straw or row crop stubble. No-till will help create a firm, moist soil at planting time; save time; and cut costs. Whether no-tilled or tilled, make sure there are no weeds growing when alfalfa is planted. Also, be sure there is no herbicide carryover from a previous crop that could injure the seedling alfalfa. Glean, Finesse, Amber, Ally, Ally Extra, Maverick, Olympus, Rave, and Peak may cause carryover concerns. Spirit, Equip, Steadfast, and atrazine-containing herbicides used on row crops the previous year also can carry over and damage newlyplanted alfalfa. Producers should consider applying a herbicide to control weeds during alfalfa establishment. Treflan can be used as a preplant incorporated treatment in conventional tillage for control of annual grasses and pigweeds. However, Treflan will not control large-seeded weeds, such as velvetleaf and cocklebur. It also can sometimes reduce alfalfa emergence if the alfalfa was seeded a little too deep, and if cool, wet weather occurs following planting. Postemergence herbicides for alfalfa include Roundup (Roundup Ready varieties only), Buctril, Butyrac 200, Poast Plus, Select, Raptor, and Pursuit. Buctril and Butyrac 200 will control certain broadleaf weeds, while Poast Plus and Select are labeled for grass control. Raptor and Pursuit can control both broadleaf and grass weeds in alfalfa. Be sure to read and follow all label directions when using any pesticide. When seeding alfalfa, plant seed ¼ to ½ inch deep. Never plant less than ¾ inch deep in sandy soils, unless the field is irrigated. For dryland production, use a seeding rate of 10 to 12 pounds per acre in the west, and 12 to 16 pounds per acre in central and eastern Kansas. For irrigation production, use 15 to 20 pounds of seed per acre in all soils When selecting seed, producers should be sure to use certified, treated seed. Varieties with a fall dormancy rating of 3 to 4 are best for the northern part of the state. For southern areas of the state, select a variety with a fall dormancy rating of 4 to 5. It is also important to select a variety with resistance to one or more of the following: phytophthora root rot, bacterial wilt, fusarium wilt, verticillium wilt, anthracnose, pea

3 aphid, spotted alfalfa aphid, and other diseases and insects. This will help increase the longevity of the stand. Producers should be sure to inoculate the seed to help ensure the nitrogen fixation necessary for optimum production. -- Jim Shroyer, State Extension Agronomy Leader Dallas Peterson, Weed management specialist 2. Full-rate and reduced-rate residual herbicide programs for corn In last week s issue, we began a discussion of weed control in corn. In this week s issue, we continue with more details about full-rate and reduced-rate residual herbicide programs for corn. Full-rate residual herbicide program This approach usually involves residual products that combine atrazine with one of the acetamide herbicides. Examples of just a few such premixes include Bicep II Magnum, BreakFree, Bullet, Guardsman Max, Propel ATZ, Lariat, Harness Xtra, and Keystone. There are other trade names and generic versions available. A preemerge application is often followed by a targeted postemerge herbicide. A full rate (based on soil texture) of any of these premix products applied at planting time, when properly activated by rainfall, can control essentially all crabgrass, foxtail, panicum, prairie cupgrass, barnyardgrass, and pigweeds (redroot, Palmer amaranth, waterhemps) well into the growing season. Control of grassy sandbur and other weeds on sands if iffy, as these products tend to leach on sands, leaving the surface layer with too little herbicide to be very effective. Also, we d expect this preemerge treatment to control only some of the shattercane and large-seeded broadleaf weeds such as velvetleaf, sunflower, cocklebur, and morningglory. Producers could then follow with a postemerge herbicide like NorthStar, aimed specifically at shattercane and large-seeded broadleaf weeds, if needed. With a vigorous corn crop rapidly developing a canopy, fields may stay weed-free until harvest. Best Fit: Works best in medium- and fine-textured soils and uniform ph, where residual herbicide activity is dependable, assuming activation by rainfall. Strengths: Can handle high weed pressure, killing common grasses and pigweeds as they germinate. It s comforting to have lots of weed control up front and to have more leeway for selecting and applying the postemerge follow-up treatment. Reduces dependence on special genetic traits or tech fees.

4 Weaknesses: Full rates of these premix products are costly. Plus, there s little opportunity to cut the preemerge rate and still get grass control well into the growing season. There s always a risk of not getting the rainfall needed for activating the soil-applied herbicide. If a postemerge follow-up is needed, costs increase. On fields where shattercane is a problem, producers have some good options now. Acetamide herbicides have some shattercane activity, especially early in the season when soils are cool. Acetochlor (e.g., Harness) is more active on shattercane than alachlor (Lasso, Intrro), S-metolachlor (Dual Magnum), or dimethenamid-p (Outlook). Flufenacet (Define) has the most cane activity. The best recipe for preemerge cane activity early in the season would be Define plus Balance Pro, since both have some activity. Usually, a postemerge treatment will still be needed for cane control later in the season. The acetamide/atrazine products are not the only choices for residual weed control in corn. There are other good broad-spectrum preplant or preemerge residual products available, including Hornet, Balance Pro, and Callisto and premix products containing those herbicides. Adding Hornet to a full rate of an acetamide/atrazine mix as a preemerge treatment can add considerably to large-seeded broadleaf weed control. Sunflower appears to be most sensitive to Hornet, followed closely by cocklebur and velvetleaf. Morningglory is less sensitive. Depending on weed species present, control may be improved enough that a postemerge treatment is not needed. Where isoxaflutole is labeled, adding Balance Pro, or using Radius (or Epic) plus atrazine, can improve the chance at one-shot preemerge control. Balance is very good on velvetleaf, pigweeds, kochia, smartweed, and Russian thistle, and helps on shattercane (although cane is not listed as controlled). However, Balance is variable on sunflower, and weak on morningglory and cocklebur. Where the weed spectrum fits and soil texture is favorable, a 2/3 rate of Balance Pro plus 2/3 rate of acetamide/atrazine applied preemerge may give one-shot control. Balance Pro (in areas where its use is permitted) and atrazine, applied before corn emerges, can also give excellent burndown of chickweeds, henbit, and many other broadleaf winter annuals. If winter annual grasses are present, adding some glyphosate to the Balance-atrazine mixture would be economical and effective. Callisto is also available for preemerge use in corn. Lumax and Lexar contain Callisto along with Dual Magnum and atrazine. Callisto has the same mode of action as Balance, but corn tolerance is better, and it can be used either preemerge or postemerge. Its activity on broadleaf weeds is similar to that of Balance, but it does not kill shattercane. Reduced-rate residual herbicide program

5 If a full-rate of a residual preplant or preemerge herbicide isn t used, producers who want to rely on a postemerge herbicide application should use at least a reduced-rate in most cases. Several herbicides can nicely complement a postemerge herbicide when used at reduced rates. Where heavy summer annual grass pressure is expected, an application of a half-rate of a residual grass herbicide (acetochlor, alachlor, dimethenamid, metolachlor, flufenacet) can give partial control for several weeks. This can greatly improve the effectiveness of a postemerge herbicide application, and give the producer more leeway on application timing. In fields with normal weed and grass infestations, a half-rate of an acetamide/atrazine premix product applied preemerge, followed by a postemerge application can do a good job. The purpose of the low-rate preemerge treatment is to kill the easy weeds (common annual grasses and pigweeds), get corn off to a head start, keep the weed infestation manageable, and buy time. Using a reduced-rate of a residual herbicide followed by a planned postemerge application can be a good fit on problem soils, such as fields with variable texture or ph, where residual herbicide performance is less dependable, or on coarse-textured soils where residual herbicides leach away too quickly. Strengths: This is often more economical than using the full-rate preemerge approach. Less dependence on timely and adequate rainfall to activate preemerge activity. Can control grassy sandbur on sandy soils. Weaknesses: Timing of the postemerge application is more critical; too much application delay due to weather, and the weed infestation can get out of control. Young corn is readily stunted by heavy weed infestations controlled too late. If producers are planning to use a broad-spectrum postemerge herbicide, they have several options for adjusting the cheap, low-rate preemerge treatment to fit their weed spectrum and infestation levels. (a) If grass pressure is light and consists mostly of foxtail, they may want to start with a 2/3 to full rate of atrazine alone, applied late preplant or preemerge. This may be all that s needed to control grass and pigweeds well into the growing season, leaving mostly shattercane and large-seeded broadleaf weeds for the postemerge treatment. This would be very economical, and could be adequate for fields with a history of very good weed control. Some no-till fields may require no more than this. If weeds in young corn are mostly small annual broadleaf weeds, then an early postemerge application of atrazine with crop oil concentrate can give excellent control. (b) Glyphosate can be doctored up to improve control in GT corn. Because glyphosate has no residual activity, several applications may be needed for season-long control. Adding Resolve adds residual shattercane control. Of course, other residual products may

6 also be used, provided they are safe to apply over growing corn. For this, Monsanto offers FieldMaster (glyphosate plus Harness plus atrazine) and Syngenta offers Expert (glyphosate plus Dual II Magnum plus atrazine). -- Dave Regehr, Weed Management Specialist 3. Canola research and field tours This spring will be a good time to assess the winterhardiness of canola varieties, both commercial and experimentals. There may have been some good selection pressure this winter where there was no continuous snow cover to protect the canola from cold temperatures. In our breeding program, we have nine advanced experimental lines entered in the National Winter Canola Variety Trials, including one line that may be proposed for release this fall. In addition, we have 110 new populations being tested in Kansas and Oklahoma. For those who want to get a complete update on canola varieties and production, there are two field tours coming up in April. Agent Field Tour: April 18. This tour is intended to train and update agricultural agents and other research and extension personnel on the use of canola in crop rotations, the importance of soil fertility and its effects on survival, and the latest cultivars available to producers in the region. It is a great opportunity for agents with a focus on crop production as well as those in counties or districts with the potential for increasing canola acres currently most counties and districts in Kansas. Please RSVP to Troy Lynn Eckart by April 4, 2007, by ing her at sprite@ksu.edu or by calling Producer Field Tour: April 25. Producers who are interested in canola will want to attend this producer-oriented field tour. Participants will learn about using canola in crop rotations, the importance of soil fertility and its effects on survival, and the latest cultivars available in the region. Both tours will begin at 9 a.m. at the Clark Woodworth farm near Sterling, and will proceed to the Partridge Research Farm and the South-Central Experiment Field operated by K-State Research and Extension. Directions to the first stop: From the junction of U.S. Hwy 50 and K-14, go 8 miles west to S. Langdon Rd. Turn right (north) on S. Langdon Rd. and drive 12 miles to W. 95th Ave. At the stop sign, turn right (east) and drive 2 miles to the field on the SE corner of the intersection of W. 95th Ave. and Lerado Rd.

7 -- Mike Stamm, Canola Breeder -- Kraig Roozeboom, Crop Production/Cropping Systems Specialist 4. Are liquid fertilizers better than dry fertilizers? Questions about the agronomic differences among the various fertilizer products found in the marketplace are sometimes raised. One of the more common questions is: Are liquid fertilizers better than dry fertilizers? Liquid UAN solution (28 or 32 percent N) is simply a mixture of urea, ammonium nitrate, and a little water and not really much water. Each gallon of 32 percent UAN solution is only 20 percent water by weight. Or, viewed another way, each gallon of 32 percent UAN solution contains roughly one quart of water by volume. The remaining weight/volume consists of dissolved urea and ammonium nitrate. Since UAN solution is mainly urea and ammonium nitrate, it is agronomically equal to dry urea and ammonium nitrate, and has the characteristics of both. Liquid is composed of a mixture of ammonium polyphosphates and ammonium orthophosphates dissolved in water. The dissolved ammonium orthophosphates are identical to dry MAP (e.g ) and/or DAP (e.g ). The dissolved ammonium polyphosphates are quickly converted by soil enzymes to orthophosphates identical to those provided by MAP and/or DAP. Polyphosphates were not developed by the fluid fertilizer industry because of agronomic performance issues. Instead, polyphosphates were developed to improve the storage characteristics of fluid phosphate products (and other fertilizers made from them) and to increase the analysis of liquid phosphate fertilizers. Ammonium polyphosphate is equal in agronomic performance to ammonium orthophosphates when applied at the same P 2 O 5 rates in a similar manner. And liquid phosphate products are equal in agronomic performance to dry phosphate products if applied at equal P 2 O 5 rates in a similar manner. There is really no agronomic difference between dry and liquid fertilizers (N, P and other nutrients) other than their physical form, how they are handled/applied, and their adaptability to the overall crop production operation. The choice of which specific fertilizer product to use should be based on: Equipment needed to handle and apply the product Logistics of hauling/nursing/applying the needed crop nutrients Adaptability to the overall farm operation and other cultural practices Personal preference Product availability

8 Cost -- Dale Leikam, Nutrient Management Specialist These e-updates are a regular weekly item from K-State Extension Agronomy. All of the Research and Extension faculty in Agronomy will be involved as sources from time to time. If you have any questions or suggestions for topics you'd like to have us address in this weekly update, contact Jim Shroyer, Research and Extension Crop Production Specialist and State Extension Agronomy Leader jshroyer@ksu.edu