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Nitrogen Management for Heavy Clay Soils

Nitrogen Management for Heavy Clay Soils. David Dunn, Andrea Phillips, & Gene Stevens University of Missouri Delta Center This Research Made Possible by a Grant from Cotton Inc. and the Missouri State Support Committee. University of Missouri Main campus. Kansas City. Columbia. St. Louis.

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Nitrogen Management for Heavy Clay Soils

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  1. Nitrogen Management for Heavy Clay Soils David Dunn, Andrea Phillips, & Gene Stevens University of Missouri Delta Center This Research Made Possible by a Grant from Cotton Inc. and the Missouri State Support Committee

  2. University of Missouri Main campus Kansas City Columbia St. Louis Springfield Bootheel MU Delta Center Portageville

  3. Dr. Bobby Phipps

  4. Objective: Develop a nitrogen management package for aggressively irrigated cotton on heavy clay soils in Missouri.

  5. Methods and Materials:Site location • Sharkey Clay soil • very fine, montmorillonite, thermic Vertic Haplaquept • pH: 7.1 P: 105 lb/a K 536 lb/a; CEC: 28.6 meq/100gr • N recommendation: • 800 lb lint = 110 lb N/a • 1000 lb lint = 130 lb N/a

  6. Methods and Materials: • 5 N rates • 0, 50, 100, 150, & 200 lbs/acre as NH4NO3 • 3 application timings • All pre-plant (PP) • 2 equal splits (pp + pin head square PHS) • 3 equal splits (PP + PHS + full bloom FB)

  7. ANOVA Table for yield Year <.0001 N rate <.0001 N*year 0.0653 Splits 0.0142 Splits*year 0.5423 N*splits 0.7202 N*splits*year 0.3734

  8. 2-Year Average Lint Yields • N rate Splits Yield • 0 ----- 244 f • 50 1 469 e • 1 595 d • 100 2 604 d • 100 3 671 cd • 150 1 692 cd • 150 2 757 bc • 150 3 753 bc • 200 1 757 bc • 200 2 837 ab • 200 3 884 a

  9. A B C D E 0 50 100 150 200 N-Rate (lb N/a) 2-Year Average yields for all application timings

  10. 900 A 800 Lint Yield (lb N/a) 700 AB B 600 1 2 3 # of Splits 2-Year Average yields for 100, 150 & 200 lb N rates

  11. Fiber properties effects: 2005 Property + N-rate + Splits Turn out -- -- Mic + - Length ++ ++ Strength + + Uniformity ** ** Leaf + ++ Value - ** + = general increase: ++ = consistent increase - = general decrease: -- = consistent decrease ** = no consistent effect

  12. Net Returns to Producers Were Calculated By: • Commodity Credit Corporation Cotton loan rates for 2006 crop year $0.5235 / lb lint • Nitrogen priced @ $0.24/ lbs N + application cost of $5.00/acre

  13. 2-Year Average net returns • N rate Splits $/acre • 0 ----- $127 • 50 1 $219 • 1 $230 • 100 2 $283 • 100 3 $312 • 150 1 $321 • 150 2 $350 • 150 3 $342 • 200 1 $343 • 200 2 $380 • 200 3 $400

  14. $225 $211 $165 $98 50 100 150 200 N-Rate (lb N/a) 2-Year Average value added by N for all application timings

  15. $225 $211 $189 2-Year Average value added by N for 100, 150 & 200 lb N rates # of splits

  16. Conclusions: • Current MU N recommendations for cotton grown on heavy clay soils may be too low. • N-rates above recommendations continued to add value • 200 lbs N best rate • Splitting N applications a profitable practice • 3 splits best strategy • More study is needed

  17. Questions?

  18. Mark your Calendar for the 46th Delta Center Field Day August 31, 2007 9:00 AM Portageville, MO

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