Using Phosphorus, Ammonium-nitrogen and Strip-kill to Increase Tall Fescue Seed Production in Missouri Missouri Fertilizer and Lime Council

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1 Using Phosphorus, Ammonium-nitrogen and Strip-kill to Increase Tall Fescue Seed Production in Missouri 2005 Missouri Fertilizer and Lime Council Grant Proposal Investigator: Dale G. Blevins, Professor & Kemper Fellow, Division of Plant Sciences, University of Missouri-Columbia Objective: To determine if tall fescue seed production in Missouri can be increased by late summer phosphorus (P) and ammonium (NH 4 + ) applications in a strip-kill management system. In several plant species, a fall NH 4 + application increases the production of the hormone, cytokinin, by root tips, and this hormone triggers reproductive growth that will culminate in seed production the next spring (Marschner 1995). We have treated tall fescue pastures on low P soils in SW Missouri with P fertilization for many years without increasing seed yields. In a recent preliminary experiment, we killed 7.5 strips of tall fescue with Roundup in late August and left 7.5 strips of live fescue for seed production. As a control, we left some plots untreated with Roundup before P was applied. We increased seed yields by 300% with the P treatments, but only in the strip-kill plots (Fig. 1). It is our hypothesis that tall fescue pastures become rootbound over time. Historically, skim plowing was used to alleviate this problem, however, this method can cause erosion problems on steep slopes. The strip-kill process would provide a noninvasive way to revitalize the root system of tall fescue without disturbing the soil. Reducing the density of roots in a pasture would allow new roots to proliferate. The increase in formation of root tips would result in greater cytokinin production to increase overall seed production. The turf industry recommends aeration and verti-slicing of lawns for the same reasons. Another benefit of this strip-kill management practice would be an increase in light penetration in the canopy of tall fescue which would lead to an increase in tiller initiation. More tillers would result in more seed heads per unit of area translating into higher seed yields. Combining the application of P and NH 4 + with the strip-kill system would lead to greater seed yields for producers. Procedure: During the third week of August 2006, tall fescue (K31, endophyte infected) pastures at the SW Center near Mt. Vernon and at the Bradford Agronomy Research Center near Columbia will be selected and forage removed to a height of 4. Soil samples will be collected and tested for P, Mg, Ca and K concentrations. Plots will be 10 x 25 with 5 alleys. Ten days after forage is removed Roundup will be applied in 7.5 strips leaving 7.5 of live tall fescue. A Roundup concentration of 2 oz/gal of water and 0.5 oz of crop oil/gal will be used for the strip-kill process. One half of the plot areas will not be treated with Roundup and this will be used for conventional tall fescue seed production. Plots will be treated with 0 or 100 lbs P/acre from triple super phosphate (0-46-0) and 0 or 100 lbs of N/acre as ammonium. Three different sources of ammonium will be used: one source will be ammonium beads from Specialty Fertilizer Products and the other sources will be supplied as urea and ammonium nitrate. Therefore, the experimental design will consist of 8 fertilizer treatment combinations, 2 management treatments (stripkill/none), 6 replications, and 2 sites for a total of 192 plots. Once the seed is mature (early to mid-june), it will be harvested and yields and specific seed weight will be determined for each plot. The same plots will be used in 2007 without further

2 Roundup treatments. Near the end of August, nitrogen will be applied as in 2006, and only 50 lbs of P will be applied to P treated plots. Current Status/Importance of Research Area: Missouri leads the nation in production of the common, non-certified forage-type of tall fescue (K31) seed. On the average, we produce million lbs of tall fescue seed per year on ~320,000 acres, for an average yield of ~200 lbs of seed produced/acre (USDA National Agricultural Statistics Service 2002). Oregon is the leading state in turf-type tall fescue seed production and the production of certified tall fescue seed for pastures. In Oregon, where tall fescue is grown in rows similar to wheat, seed yields average nearly 1,500 lbs/acre. However, in Missouri, pastures are managed for grazing and seed is harvested as a by-product of the overall forage system. As such, our yields are considerably lower than those of Oregon. Providing beef producers with a management scheme that would improve seed yields without impacting forage production on most of their acreage would increase overall farm profits. We have used strip-kill techniques to successfully grow forage sorghum and grain sorghum in tall fescue pastures (Reinbott and Blevins 1995). Yields of both forage sorghum and grain sorghum were good and forage yields of the tall fescue were unaffected by this management practice. We also found that annual spraying was not necessary to maintain killed strips. Opening up the canopy by cutting the tall fescue during the third week of August, then removing underground competition with strip-kill should allow robust root growth. This, coupled with cytokinin production following the application of ammonium, should result in greater seed production the following spring. Citrus research in southern California showed that a fall application of ammonium-nitrogen is superior to fall application of nitratenitrogen for stimulating cytokinin production, and fruit set the subsequent spring (Marschner 1995). Timetable for proposed research: In mid-summer 2006, tall fescue areas at the Southwest Center and the Bradford Agronomy Research Center will be identified and soil samples collected and analyzed. During the third week of August, tall fescue forage will be cut removed from the plot areas. About 10 days later, strips will be killed and the P and N treatments will be applied. Seed maturity status will be monitored starting in May of 2007 and seed will be harvested around mid-june. Forage will be allowed to grow, and the same plots areas without additional Roundup treatment will be used in Near the end of August, nitrogen will be applied as in 2006, and only 50 lbs of P will be applied to P treated plots. At the end of the experiment, data from the two years and two locations will be analyzed by SAS and graphs will be prepared by plotting yields and specific seed weights versus treatment combinations, location and year. Strategy for application/transfer of knowledge: Results from this study will be presented at Southwest Center Field Days and other field days around the state, and regional newspaper and agricultural magazine articles will be prepared in advance of the field days by agricultural journalists. After the second year, a paper will be presented at the American Society of Agronomy meetings, and a refereed journal article will be prepared for publication.

3 Seed Yield (lbs/a Continuous Stripkill P (lbs/acre) Figure tall fescue seed yields from stripkill and continuous plots treated with various rates of P fertilization. Data from a preliminary study conducted at the Bradford Agronomy Research Center near Columbia, Mo and data are means of 6 plots ± SE. Budget: Category Year 1 Year 2 Total Salary Research Assistant (25%) $8,000 $8,500 $16,500 Benefits 2,000 2,125 4,125 Supplies (fertilizer, Roundup, nozzles, gas) 1,000 1,000 2,000 Travel to Mt. Vernon ,500 Total $11,759 $12,375 $24,125 Reference List: Marschner H Mineral Nutrition of Higher Plants. Elsevier Science, Academic Press, Amsterdam, Netherlands. Reinbott, T.M. and Blevins, D.G Multiyear use of killed strips for forage and grain sorghum production in a tall fescue pasture. J. Production Agriculture 8: Resume: Dale G. Blevins - Professor of Agronomy Present Address Division of Plant Sciences phone Agriculture Building fax University of Missouri blevinsd@missouri.edu Columbia, MO Education B.S. in Chemistry, Southwest Missouri State University, 1965 M.S. in Soils (Plant Nutrition), University of Missouri, 1967 Ph.D. in Plant Physiology, University of Kentucky, 1972

4 Experience present, Professor, Agronomy Department, U. Missouri, Columbia Associate Professor, Agronomy Department, U. Missouri, Columbia Assistant Professor, Agronomy Department, U. Missouri, Columbia Assistant Professor, Botany Dept., U. Maryland, College Park Postdoctoral Research Associate, Department of Botany and Plant Pathology, Oregon State University, Corvallis Awards 1982 Gamma Sigma Delta Superior Research Award for Junior Faculty in Agriculture 1983 Amer. Soybean Assoc./ ICI International Soybean Researchers Recognition Award 1983 Gamma Sigma Delta Superior Graduate Teaching Award 1992 Fellow of the American Society of Agronomy 1992 Fellow of the Crop Science of America 1992 Distinguished Faculty Award, UMC Alumni 1993 Kemper Teaching Award, UMC Selected Publications Reinbott, T.M. and D.G. Blevins Phosphorus and magnesium fertilization interaction with soil phosphorus level: Tall fescue yield and mineral element content. J. Production Agriculture 10: Reinbott, T.M., D.G. Blevins and M.K. Schon Content of boron and other elements in main stem and branch leaves and seed of soybean. J. Plant Nutrition 20: Blevins, D.G. and T.M. Reinbott Impact of phosphorus nutrition on magnesium, calcium and water status of plants. Current Topics in Plant Physiology: An American Society of Plant Physiologists Series 19: Blevins D.G. and K.M. Lukaszewski Boron in plant structure and function. Annual Review of Plant Physiology and Plant Molecular Biology 49: Markwell, J. and D.G. Blevins The Minolta Spad-502 leaf chlorophyll meter: An exciting new tool for education in the plant sciences. The American Biology Teacher 61: Reinbott, T. M. and D.G. Blevins Phosphorus nutritional effects on root hydraulic conductance, xylem water flow and flux of magnesium and calcium in squash plants. Plant and Soil 209: Waters, B.M. and D.G. Blevins Ethylene production, cluster root formation and localization of iron (III) reducing capacity in Fe deficient squash roots. Plant and Soil 225: Smith, G.J., W.J. Wiebold, T.L. Niblack, P.C. Scharf and D.G. Blevins Yield components of soybean plants infected with soybean cyst nematode and sprayed with foliar applications of boron and magnesium. J. Plant Nutrition 23: Smith, G.J., W.J. Wiebold, T.L. Niblack, P.C. Scharf and D.G. Blevins Macronutrient concentrations of soybean infected with soybean cyst nematode. Plant and Soil 235:21-26.

5 Lock, T.R., R.L. Kallenbach, D.G. Blevins, T.M. Reinbott, G.J. Bishop-Hurley, R.J. Crawford, Jr. and M.D. Massie Soil phosphorus may be important to beef herd health and performance. Better Crops with Plant Food 85:4-8. Waters, B.M., D.G. Blevins and D.J. Eide Characterization of FRO1, a pea (Pisum sativum) ferric-chelate reductase involved in root Fe uptake and tissue Fe distribution. Plant Physiol. 129:1-10. Lock, T.R., R.L. Kallenbach, D.G. Blevins, T.M. Reinbott and G.J. Bishop-Hurley Adequate soil phosphorus decreases the grass tetany potential of tall fescue pasture. Online. Crop Management doi: /cm rs. Lock, T.R., R.L. Kallenbach, D.G. Blevins, T.M. Reinbott, G.J. Bishop-Hurley, R.J. Crawford, M.D. Massie and J.W. Tyler Plant Management Network. June 8:1-8. Reinbott, T.M., S. P. Conley, and D. G. Blevins No-Tillage Corn and Grain Sorghum Response to Cover Crop and Nitrogen Fertilization Agron. J. 96: Blevins, D.G., M. Massie and W. McClain Phosphorus fertilization improves quality of stockpiled tall fescue. Better Crops with Plant Food 88:7-9. Bolanos, L., K. Lukaszewski, I. Bonilla and D. Blevins Why boron? A Reviw. Plant Physiology and Biochemistry 42: Todd, C.D., P.A. Tipton, D.G. Blevins, P. Piedras, M. Pineda and J.C. Polacco Update on ureide degradation in legumes. J. Experimental Botany. doi: /jxb/erj013