effect of nitrogen sources, rates, and application time on spring wheat yield and grain protein olga...
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Effect of Nitrogen Sources, Rates, and Application Timeon Spring Wheat Yield and Grain Protein
Olga S. Walsh, Western Triangle Agricultural Research Center, Conrad, Montana
JUSTIFICATION
EVALUATED FACTORS
Fertilizer Timing: Preplant vs TopdressPreplantSupplies N to establish crop standBetter soil/weather conditions (Randall and
Schmitt, 1998)Risk of N loss (immobilization, volatilization)
(Fowler and Brydon, 1989; Wuest and Cassman, 1992)
TopdressSupplies N at maximum plant uptake – higher
NUE (Walsh et al., in press)N fertilization after Feekes 5 – crop can catch
up (Morris et. al., 2005)Enables fertilization based on crop need/yield
potential
Fertilizer Sources: Granular vs LiquidGranular N (urea)Up to 30% N loss as ammonia forbroadcasted urea (Engel, personal
communication) Urea applied with the seed – seed damage,
drying out of seed bed – affects germination
Liquid N (urea ammonium nitrate = UAN) Plants absorb water and nutrients through
leaves (Wittwer and Teubner, 1959) Efficiency of foliar fertilizers is higher(Mosali et al., 2006) Crop injury/leaf burn (Wesley et al., 1998)
MATERIALS AND METHODS
3 dryland experimental sites: Western Triangle Research Center, Conrad, MT, 2 on-farm studies (Jack Patton, Knees, Chouteau County, MT and Pat Wheeler, Valier, Pondera County, MT)Choteau spring wheat variety4 preplant N rates (0, 40, 80, and 120 lbs N
ac)3 topdress N rates (0, 40, and 80 lb N ac)2 topdress N fertilizer sources (granual –
urea, 46-0-0, and liquid – urea ammonium nitrate (UAN) , 28-0-0)2 topdress application times (before
flowering and after flowering)
To determine the most efficient N fertilizer source, N rate, and N fertilizer application time combination for optimizing Montana spring wheat yield while maximizing grain protein
OBJECTIVE
AKNOWLEDGEMENTS: We are grateful to: Mr. Jack Patton and Mr. Pat Wheeler for support and cooperation, Mr. Clint Rouns and Mr. John Miller (WTARC, MSU), and Dan Picard (Pondera County Extension Agent, MSU), for their expertise and support
We are grateful to Montana Fertilizer Advisory Committee for funding this project
Dr. Olga S. Walsh, WTARC, MSUtelephone: (406)278-7707
e-mail: [email protected]: http://ag.montana.edu/wtarc/
Nitrogen (N) - the most common nutrientlimiting yield of spring wheat in Montana(Engel, 1993)Spring wheat - key cereal crop grown in
MontanaWheat production represents ~ 25% of
Montana’s agricultural revenue (stuffaboutstates.com, 2010)Protein content - base for established market
adjustments for spring wheat, with premiums paid for increase above the baseline levels
DISCUSSION
Data from WTARC and Patton are evaluated for 2011Spring wheat mean grain yield was higher at
WTARC (1735 kg ha-1) compared to Patton (1544 kg ha-1)Yields ranged from 618 to 2047 kg ha-1 at
WTARC and from 1262 to 2004 kg ha-1 at PattonGreater response to fertilizer N observed at
WTARC; unfertilized check yielded twice as high at Patton, compared to WTARCPreplant N rate and topdress application time
significantly effected yield at both sites (p<0.05)At WTARC, fertilization before flowering
resulted in greater mean spring wheat yield (1432 kg ha-1) compared to after flowering (1274 kg ha-1)Fertilizer N source had no significant effect on
spring wheat yields
CONTACT INFORMATION
Figures 1a and 1b. Effect of fertilizer N rate, source and application time on spring wheat grain yield at WTARC (1a) and Patton (1b), 2011.
400
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736
1843 1833
1231 1267 12291373
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TreatmentS
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ield
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ha-1
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Figure 1a
1350
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1478
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Treatment
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Figure 1b
RESULTS
Leaf burn apparent in spring wheat following application of UAN at 90 kg N ha-1 rate before flowering at WTARCSpring wheat grain yields were not
impacted by foliar UAN application before flowering at WTARCFoliar application of UAN at 90 kg N
ha-1 rate negatively impacted yields at Patton; plots topdressed at 45 kg N ha-1 rate yielded significantly higher, independent of application time.