HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Fiez, T. E. Articles by Miller, B. C. Search for Related Content PubMed Articles by Fiez, T. E. Articles by Miller, B. C. Agricola Articles by Fiez, T. E. Articles by Miller, B. C.

Nitrogen Use Efficiency of Winter Wheat among Landscape Positions

Department of Crop and Soil Sciences, Washington State Univ., Pullman, WA 99164-6420

*Corresponding author (pan{at}wsuvml.csc.wsu.edu).

ABSTRACT

Spatially variable N fertilizer application may reduce environmental impacts and increase the economic return of N fertilization. To achieve these benefits, N recommendations must account for within-field differences in the amount of N required to produce a unit of yield (unit N requirement, UNR). Component analysis was used to determine the sources of variation in the UNRs of winter wheat (Triticum aestivum L.) among landscape positions. The UNRs were divided into two components, N uptake efficiency (plant N/N supply) and N utilization efficiency (grain yield/plant N) observed in N rate trials (0–140 kg N ha^–1 fall applications) established on footslope, south backslope, shoulder, and north backslope positions of two farms for 2 yr. Variation in the UNR among the 16 landscape positions studied was most associated with differences in N uptake efficiency (r = –0.80), although N utilization efficiency (r = –0.62) also contributed to the variation. Nitrogen uptake efficiency among landscape positions declined as more fertilizer was required to reach optimum yield (r = –0.56) due to low N fertilizer uptake efficiencies (plant N/N fertilizer). Nitrogen fertilizer uptake efficiency was related to the degree of apparent N loss (r = –0.87), indicating that N availability limited N uptake efficiency among landscapes. Overall, low N fertilizer uptake efficiencies (<50%) and high N loss percentages (>50%) indicate the need to reduce N losses and lower UNRs, particularly on north-facing backslopes susceptible to N leaching.

WSU Crop and Soil Sciences Departmental Paper no. 9406-08.

Received for publication June 20, 1994.

This article has been cited by other articles:

				Z. Cui, X. Chen, Y. Miao, F. Zhang, Q. Sun, J. Schroder, H. Zhang, J. Li, L. Shi, J. Xu, et al. On-Farm Evaluation of the Improved Soil Nmin-based Nitrogen Management for Summer Maize in North China Plain Agron. J., May 7, 2008; 100(3): 517 - 525. [Abstract] [Full Text] [PDF]

				Y. Miao, D. J. Mulla, P. C. Robert, and J. A. Hernandez Within-Field Variation in Corn Yield and Grain Quality Responses to Nitrogen Fertilization and Hybrid Selection Agron. J., January 5, 2006; 98(1): 129 - 140. [Abstract] [Full Text] [PDF]

				K. F. Bronson, J. W. Keeling, J. D. Booker, T. T. Chua, T. A. Wheeler, R. K. Boman, and R. J. Lascano Influence of Landscape Position, Soil Series, and Phosphorus Fertilizer on Cotton Lint Yield Agron. J., July 1, 2003; 95(4): 949 - 957. [Abstract] [Full Text] [PDF]

				M. Mamo, G. L. Malzer, D. J. Mulla, D. R. Huggins, and J. Strock Spatial and Temporal Variation in Economically Optimum Nitrogen Rate for Corn Agron. J., July 1, 2003; 95(4): 958 - 964. [Abstract] [Full Text] [PDF]

				A. J. Eagle, J. A. Bird, W. R. Horwath, B. A. Linquist, S. M. Brouder, J. E. Hill, and C. van Kessel Rice Yield and Nitrogen Utilization Efficiency under Alternative Straw Management Practices Agron. J., November 1, 2000; 92(6): 1096 - 1103. [Abstract] [Full Text]