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Production Papers

Nitrogen Management for Mid-Atlantic Hard Red Winter Wheat Production

^a Dep. of Natural Resource Sciences and Landscape Architecture, Univ. of Maryland, Room 1112-B, H.J. Patterson Hall, College Park, MD 20742-4452
^b Central Maryland Research and Education Center, 12000 Beaverdam Road, Laurel, MD 20708
^c Wye Research and Education Center, P.O. Box 169, Queenstown, MD 21658

^* Corresponding author (rkratoch{at}umd.edu)

Received for publication April 5, 2004.

	ABSTRACT

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
Although soft red winter wheat (SRWW) (Triticum aestivum L.) is the predominant class in the Mid-Atlantic, there is a recently established program for producers to grow hard red winter wheat (HRWW). This program offers a base price plus premiums for HRWW meeting quality (test weight and protein content) standards. This study's objectives were to evaluate the effect of N management strategies on HRWW yield and protein content and to determine the economic return using those strategies. Two HRWW cultivars used by producers in this HRWW program were produced at two locations in Maryland in a split plot arrangement of N treatments within a randomized complete block experimental design. Main plots (2002) were a factorial arrangement of those cultivars and four fall and Feekes growth stage (GS) 2/3 N treatments. Split plots (2002) were eight N timing and rate combinations at GS 5/6, GS 8, and/or GS 10.1. Main plots (2003) were a factorial arrangement of the cultivars and fall N supplied by either ammonium sulfate (AS) or urea-ammonium nitrate (UAN) and GS 2/3 N treatments. Split plots (2003) were GS 5/6, GS 8, and 10.1 N timing and rate combinations. Wheat yield was significantly improved with GS 8 and/or 10.1 N applications both years. Protein content responded to GS 8 and 10.1 N applications in 2002; however, the response in 2003 was dependent on location and N amount at GS 5/6. Within the price and premium structure, best return was observed for split applications of N; 50 or 68 kg ha^–1 at GS 2/3 followed at GS 5/6 with 50 or 68 kg N ha^–1. No fall N benefit was observed.

Abbreviations: AS, ammonium sulfate • CMREC, Central Maryland Research and Education Center • GS, growth stage • HRWW, hard red winter wheat • SRWW, soft red winter wheat • UAN, urea-ammonium nitrate • WREC, Wye Research and Education Center

	INTRODUCTION

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
ALTHOUGH SOFT RED WINTER WHEAT (SRWW) is the predominant wheat class in the Mid-Atlantic, there has been a recent program available for the region's wheat producers to grow hard red winter wheat (HRWW). This program originated as an attempt by one of the region's largest flour milling companies to reduce operational costs by importing less HRWW from U.S. production regions for that class of wheat. This contract production opportunity has offered producers premiums for quality grain to encourage more production of HRWW. Quality grain for this program has been defined as test weight of 772 kg m^–3 or greater and protein content of 110 gm kg^–1 or greater (W. Knerr, personal communication, 2003).

Since the Mid-Atlantic is a SRWW production area, one limiting factor to successful production of HRWW is the lack of adapted cultivars. Two HRWW cultivars, Agripro brand ‘Charter’ and ‘Hondo’ have performed comparably to top-producing SRWW cultivars in cultivar performance tests in Maryland (Costa et al., 2001, 2002). The second limiting factor to successful production is the identification of N management practices for production of high protein HRWW worthy of premiums.

It is well documented that N is the primary nutrient that influences both grain yield and protein concentration (McNeal and Davis, 1954; Terman et al., 1969; Olson et al., 1976; Grant et al., 1985). In the environmentally sensitive Chesapeake Bay drainage area that encompasses a large portion of the Mid-Atlantic region, proper N management is important and in some cases it has become mandatory (Simpson, 1998). Producers of high-yielding SRWW have long utilized split applications of N [one-half at Feekes (Large, 1954) growth stages (GS) 2/3 and the remainder at Feekes GS 5/6] (Sammons et al., 1989; Bandel et al., 1989) to maximize yield while minimizing N leaching. For protein enhancement, a number of researchers have recently reported that late-season topdress of N is the most effective means for attaining better grain protein concentrations (Fowler and Brydon, 1989; Vaughn et al., 1990; Stark and Tindall, 1992; Wuest and Cassman, 1992; Knowles et al., 1994).

The objective of this project was to identify management practices for both the timing of applications and for the rates of N used to maximize profit for the production of HRWW in the Mid-Atlantic region. This project incorporated an adaptive research approach by utilizing the information attained with the field results from 2002 to adjust the treatments that were compared during the 2003 crop year. This adaptive research approach was undertaken to respond relatively quickly to the lack of N management information available to farmers in the Mid-Atlantic who were producing this alternative to SRWW. The need to identify N fertilizer strategies that were both economical for farmers and sensitive to environmental concerns was vital.

	MATERIALS AND METHODS

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
Two HRWW cultivars that were developed and are marketed specifically for production in the Mid-Atlantic region (Agripro brands Charter and Hondo) were planted at a rate of 3705000 viable seeds ha^–1 at two locations [Wye Research and Education Center (WREC) near Queenstown, MD, and Central Maryland Research and Education Center–Beltsville Facility (CMREC) near Beltsville, MD] during the 2002 production year. During 2003, Hondo was limited to CMREC whereas Charter was planted at the two locations. Planting dates at both locations during both years followed the Hessian fly (Mayetiola destructor Say)–free recommended dates and were considered within the optimal planting window. Those dates at WREC were 10 Oct. 2001 and 9 Oct. 2002 and at CMREC were 12 Oct. 2001 and 26 Oct. 2002. The soil type at WREC was a Matapex silt loam (fine-loamy, siliceous, semiactive, mesic Typic Hapludults) and at CMREC it was a Sassafras sandy loam (fine-loamy, siliceous, mesic, Alfic Normudults) (2002) and a Rumford loamy sand (coarse-loamy, siliceous, thermic, Typic Normudults) (2003).

The wheat at both locations was managed using standard pesticide practices when required. Weed control was accomplished with 73 mL ha^–1 Harmony Extra [thifensulfuron-methyl (50% by weight) and tribenuron-methyl (25% by weight)] at both locations each year. The herbicide was applied 3 Mar. 2002 and 15 Apr. 2003 at WREC and 12 Mar. 2002 and 14 Apr. 2003 at CMREC. An insecticide application of 210 g ha^–1 Warrior (lambda-cyhalothrin) was used on 7 Dec. 2001 to manage an outbreak of greenbug aphid (Schizaphis graminum Rondani) at WREC. The same insecticide and rate was used for cereal leaf beetle (Oulema melanopa L.) larvae at CMREC on 14 May 2003. The foliar fungicide, Tilt (propiconazole) was applied at a rate of 280 g ha^–1 on 17 Apr. 2002 at WREC (no fungicide was used during 2003) and 25 Apr. 2002 and 14 May 2003 at CMREC.

Plots were harvested with a Massey Ferguson 8-XP plot combine equipped with a Harvest Master data collection system (Juniper Systems, Logan, UT) that recorded grain weight, test weight, and moisture content as each plot was harvested. Harvest dates were 20 June 2002 and 30 June 2003 at WREC. The CMREC harvest dates were 25 June 2002 and 15 July 2003. Small samples (50 g) of wheat from each plot were collected during harvest and used for protein analysis. Protein was analyzed using Near Infrared Transmittance technology using an Infratec 1255 Grain Analyzer (Tecatur AB, Hoganas, Sweden).

A split plot arrangement of treatments within a randomized complete block experimental design with three replications at each location each year was used. The whole plot treatments during 2002 were a 2 x 4 factorial arrangement of the two cultivars and four fall/GS 2/3 N timing and rate applications. The N timing and rate applications were the use of either no fall N or 28 kg ha^–1 N at planting time coupled with GS 2/3 N applications of either 34 or 68 kg ha^–1 applied at Feekes GS 2/3. The split plots were N applications made at Feekes GS 5/6, 8, and/or 10.1, respectively. Growth stage 5/6 treatments were either 34 or 68 kg ha^–1. Late growth stage applications included either 0 or 17 kg ha^–1 N applied at GS 8 or 10.1 or at both 8 and 10.1. Each split plot comprised a harvest unit that was 1.5 x 9.1 m in size.

Some changes in the whole plot and split plot treatments were made for 2003 complying with the adaptive research approach used for this study. The cultivar Hondo was evaluated at only one location, CMREC, during 2003. Reasons for this change were the performance of Hondo during 2002, space limitations at WREC for 2003, and because multi-location yield performance trials conducted during 2001 and 2002 (Costa et al., 2001, 2002) had determined that Hondo consistently produced 5 to 20% less than top producing SRWW cultivars, indicating that it would not be the hard wheat cultivar of choice for Maryland producers. In those same multi-location yield tests, Charter produced over 7% more than the top producing SRWW cultivars (Costa et al., 2002). Additionally, changes were made to the fall/GS 2/3 N treatments (whole plots). Three fall N application treatments were evaluated during 2003. They were no fall N application, 28 kg ha^–1 available N using ammonium sulfate (AS), and 28 kg ha^–1 available N using urea-ammonium nitrate (UAN). Changes in GS 2/3 N treatments were also made during 2003. The lower rate for GS 2/3 N application was increased from 34 to 50 kg ha^–1. The upper rate for GS 2/3 remained at 68 kg ha^–1. For the split plot N treatments, the GS 5/6 lower application rate increased from 34 to 50 kg ha^–1 and the upper rate remained at 68 kg ha^–1. The last change based on the 2002 results was the discontinuation of the late stage application of 17 kg ha^–1 at both GS 8 and 10.1. Late stage applications during 2003 were zero and 17 kg ha^–1 N at either GS 8 or 10.1.

Economic analyses for the 2 yr were conducted using some basic assumptions regarding the wheat price received for the harvested crop and the cost of the fertilizer inputs and application expenses. The base selling price used for the wheat for 2002 was the average 2002 Pennsylvania price for SRWW for the 6-mo period (July–December 2002) following harvest ($124.68 Mg^–1) plus the $7.33 Mg^–1 premium offered per the contract for HRWW that was delivered to the designated Pennsylvania mills. The base selling price used during 2003 was $122.84 Mg^–1 with the same $7.33 Mg^–1 premium as per the contract for HRWW production. Protein premiums for each year were determined on a per-plot basis and added to the price received for wheat production for each plot. The 2002 protein premiums (established by the contract before planting 2002 crop) were $7.33, $11.00, and $14.67 Mg^–1 for protein contents of 110 to 119 g kg^–1, 120 to 129 g kg^–1, and 130 g kg^–1 or greater, respectively. During 2003, the protein premiums were reduced by the contracting company for unknown reasons to $1.83, $3.67, and $5.50 Mg^–1 for the same protein regime. Cost of application was based on custom rates for Maryland (Maryland Agric. Statistics Service, 2002a). Application of fall N was assumed done using the grain drill and at the time when the wheat was planted. One-third of the $29.64 ha^–1 planting rate ($9.88 ha^–1) was used for the fall fertilizer application cost. Growth stage 2/3 N application was made in conjunction with the application of herbicide in the spring. The custom spraying rate is $17.29 ha^–1 and $7.41 ha^–1 of that application rate was assessed for applying the N. Each of the GS 5/6, 8, and 10.1 applications was charged the full spraying rate of $17.29 ha^–1. These late stage applications were made with the assumption that tramlines were established in the field with minimum distance between tramline centers of 12 m so that the yield loss potential caused by the tramlines was negligible (Sammons et al., 1989). The cost of N was calculated on a kilogram of available N basis ($0.57 kg^–1) determined by the 2002 northeast regional average price for urea–ammonium nitrate (USDA-NASS, 2003). For 2003 calculations, AS was priced at $0.94 kg^–1 of available N using that product's 2002 average price for the south central region (USDA-NASS, 2003). Net return was the total amount received for the wheat determined by yield x (SRWW base price for the year + $7.33 Mg^–1 production premium + protein premium for each year) less the cost of inputs (costs of fertilizer used and custom application rates).

All data were subjected to analysis of variance using PROC MIXED procedure (Littell et al., 1996) of SAS (SAS Inst., 1995). Data were first analyzed combined over locations with all effects except replications considered fixed. If interactions between location and the other variables were determined, individual location analyses of variance were conducted. Mean separation analyses were conducted using Fisher's protected LSD (P 0.05) unless otherwise noted.

	RESULTS AND DISCUSSION

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
Weather
The 2 yr of this study had extraordinarily different weather conditions. The 2002 crop year started (fall 2001) with timely planting into soils that had adequate moisture for germination. The period from October 2001 through February 2002 was much drier than normal (Table 1). Near normal precipitation during March at both locations and during April at CMREC (Table 1) produced adequate levels of soil moisture for both locations allowing the crop to attain excellent grain fill. Both locations received less rainfall than normal during May and June, but this proved to be ideal weather conditions during grain fill and while the crop matured. Little disease pressure was observed during this drier than normal period. The crop was harvested at both locations on a timely basis protecting the excellent quality (i.e., test weight and yield) of the wheat. Overall, 2002 was considered ideal for wheat production and was confirmed by the state's record yield for SRWW (Maryland Agric. Statistics Service, 2002b).

Yield Results—2002
Significant yield differences were observed between the two locations and between the two cultivars. The WREC produced an average yield of 6746 kg ha^–1 over all treatments compared with 5570 kg ha^–1 at CMREC. Charter was the superior cultivar, producing 6544 kg ha^–1 averaged over the two locations compared with only 5604 kg ha^–1 for Hondo.

Hondo had wheat yields that were not significantly different across the four fall/GS 2/3 N treatments (Table 2). Field observations (no data) of Hondo indicated that it is a cultivar that produces considerably more vegetative growth than Charter. Charter produced grain yield that was comparable to Hondo for the no fall N plus 34 kg N ha^–1 at GS 2/3 treatment. For the other three fall/GS 2/3 N treatments, Charter produced significantly more grain (Table 2). The most encouraging response from a nutrient management perspective for Charter occurred for the no fall N plus 68 kg N ha^–1 at GS 2/3 that produced as well as either of the treatments that used 28 kg N ha^–1 of N in the fall (Table 2).

Protein Content—2002
A combined location ANOVA was performed for the protein data for 2002. Significant interactions were observed for location x fall/GS2/3 main plot effects and location x GS 5/6, 8, and 10.1 N management (split plot effects) so each location's protein data was analyzed separately. Hondo produced 7 to 8 g kg^–1 more protein at both locations (Table 5). There was approximately 10 g kg^–1 more protein produced at CMREC than at WREC. At CMREC, both Hondo and Charter had protein contents for the 0 fall N plus 68 kg N ha^–1 at GS 2/3 treatment that were equal to the protein contents attained for either of the two treatments that used 28 kg N ha^–1 in the fall (Table 5). The same response for both cultivars occurred at WREC for the no fall N plus 68 kg N ha^–1 treatment (Table 5). The use of fall N had not produced any yield benefit at either location during 2002 (Table 2) and now there was no protein improvement. This indicated that the use of fall N for HRWW production should consider a number of criteria including previous crop, soil type, residual N, and weather conditions rather than using it as a standard practice.

However, the combined analysis did indicate a significant location x GS 5/6, 8, and 10.1 N treatment interaction. At CMREC, 17 kg N ha^–1 applied at GS 10.1 resulted in a significant increase in protein for Charter compared with no N application at GS 8 or 10.1 for either the 50 or 68 kg N ha^–1 at GS 5/6 treatments (Table 7). This same 17 kg N ha^–1 applied at GS 10.1 at CMREC only produced significantly more protein than the 17 kg N ha^–1 applied at GS 8 when 50 kg N ha^–1 at GS 5/6 was used (Table 7). At WREC, the late stage (GS 8 or 10.1) N applications differed for the two GS 5/6 N treatments. When 50 kg N ha^–1 was applied at GS 5/6, there was a significant increase in protein when 17 kg N ha^–1 was applied at GS 8 compared with the amount of protein attained when no GS 8 or 10.1 N applications were used (Table 7). There were no significant protein content differences among the three treatments for the GS 5/6 rate of 68 kg N ha^–1 (Table 7). A key point for the late applications (GS 5/6, 8, and 10.1) during 2003 was that all treatments produced protein concentrations that met the level required by the contract to receive the maximum protein premium of $5.50 Mg^–1.

Test weight at both locations during 2002 easily exceeded 772 kg m^–3 for both Hondo and Charter. The year 2002 was an excellent small grain production year. Though precipitation amounts were below normal during the winter and spring months, there was enough rainfall received to provide adequate moisture for grain fill. Dry conditions prevailed during harvest to allow the wheat to be harvested without any rainfall events, causing reductions in test weight.

The year 2003 was the opposite of 2002 regarding precipitation. The winter and spring months received above normal precipitation with the wet conditions continuing through the grain fill and crop maturation phases of growth. Even the harvest period was affected by numerous rain events that resulted in wheat that had test weight well below the 772 kg m^–3 minimum required to be considered eligible for quality premiums.

Economic Analysis—2002
To ultimately determine the practicality for the N management treatments evaluated, an analysis of the financial return that farmers could attain using the various management strategies described in this study was conducted. A combined ANOVA over locations for the net return values for 2002 indicated that significant differences in net return were observed between the two locations and among the fall/GS 2/3 N treatments (whole plot effects) as well as for the GS 5/6, 8, and 10.1 treatments (split plot effects). Wheat produced at WREC netted approximately $148 ha^–1 more than at CMREC. This was not surprising, given the differences in soil productivity that exist between those two locations and can exist among the various soil types comprising Maryland's landscape.

For the fall/GS 2/3 treatments, there were distinct differences between the two cultivars with Charter clearly producing the better net return (Table 8). Hondo showed no differences in net return among the four fall/GS 2/3 treatments (Table 8). Charter produced the best net return when no fall N plus 68 kg N ha^–1 at GS 2/3 was used (Table 8).

Economic Analysis—2003
Since Hondo was grown only at CMREC during 2003, ANOVA for net return was conducted for each location. Hondo produced significantly less net return than Charter across all the comparable treatments (Table 10). At both locations, Charter attained a net return for both of the treatments that used 0 fall N that was not significantly different from the net return attained for the four treatments that included 28 kg N ha^–1 (Table 10).

	CONCLUSIONS

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

	ACKNOWLEDGMENTS

 
The authors express their gratitude to the farm support staffs at the Wye and Central Maryland Research and Education Centers for their significant contributions toward the successful completion of this project. This project was funded by a grant from the Chesapeake Fields Institute.

	NOTES

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
Mention of trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product by Univ. of Maryland and does not imply its approval to the exclusion of other products or vendors that may also be suitable.

	REFERENCES

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 

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This Article Abstract Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Kratochvil, R. J. Articles by Sultenfuss, M. Search for Related Content PubMed Articles by Kratochvil, R. J. Articles by Sultenfuss, M. Agricola Articles by Kratochvil, R. J. Articles by Sultenfuss, M. Related Collections Nitrogen Wheat Nutrient Management