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 Wuest, S. B. Articles by Cassman, K. G. Search for Related Content PubMed Articles by Wuest, S. B. Articles by Cassman, K. G. Agricola Articles by Wuest, S. B. Articles by Cassman, K. G.

Fertilizer-Nitrogen Use Efficiency of Irrigated Wheat: II. Partitioning Efficiency of Preplant versus Late-Season Application

Dep. Crop and Soil Sciences, Washington State Univ., Pullman, WA 99164-6420
International Rice Research Institute, P. O. Box 933, 1099 Manila, Philippines.

^* Corresponding author.

Partitioning of N to grain is an important determinant of N-use efficiency in wheat (Triticum aestivum L.). This study evaluated the effects of N-fertilizer treatments on N partitioning, and compared the partitioning of labeled N applied at planting with labeled N applied at anthesis. A 2-yr field experiment was conducted with applications of 120, 180, or 240 kg N ha^–1 at planting and 0,30, or 60 kg N ha^–1 at anthesis. The mean N harvest index (NHI) of N acquired from fertilizer applied at planting was 0.70, compared to 0.89 for that N acquired from fertilizer applied at anthesis. Mean NHI of total plant N derived from all sources (fertilizer and soil) was 0.74. The amount of N applied at anthesis had little effect on N partitioning, but increasing rates of preplant N from 120 to 240 kg N ha^–1 caused a decrease in NHI averaging 0.10 the first yr and 0.04 the second yr. A second 2-yr experiment, using similar N treatments and a small dose (<1 kg ha^–1) of NH₄^–15N injected into the soil at anthesis verified these results. In the second experiment the effects of preplant N on NHI differed between cultivars; Yecora Rojo was considerably more efficient than Anza at high preplant N rates. Fertilizer N applied at anthesis was found in leaf, stem, and spike tissue 14 days after anthesis and contributed 4.2 to 16.8% of the N in each tissue at that time. Anthesis N fertilizer was also well distributed among structural, soluble, and ribulose-1,5-diphosphate carboxylase N factions of flag leaves. This study demonstrated that the early season N environment has a large influence on N partitioning at maturity, whereas N applied at anthesis has little effect on N partitioning and is allocated more efficiently to grain.

Received for publication March 7, 1991.

This article has been cited by other articles:

				L. R. Gibson, C. D. Nance, and D. L. Karlen Winter Triticale Response to Nitrogen Fertilization when Grown after Corn or Soybean Agron. J., January 1, 2007; 99(1): 49 - 58. [Abstract] [Full Text] [PDF]

				B. L. Ma, W. Yan, L. M. Dwyer, J. Fregeau-Reid, H. D. Voldeng, Y. Dion, and H. Nass Graphic Analysis of Genotype, Environment, Nitrogen Fertilizer, and Their Interactions on Spring Wheat Yield Agron. J., January 1, 2004; 96(1): 169 - 180. [Abstract] [Full Text] [PDF]

				M. A. Melaj, H. E. Echeverria, S. C. Lopez, G. Studdert, F. Andrade, and N. O. Barbaro Timing of Nitrogen Fertilization in Wheat under Conventional and No-Tillage System Agron. J., November 1, 2003; 95(6): 1525 - 1531. [Abstract] [Full Text] [PDF]

				M. J. Ottman and N. V. Pope Nitrogen Fertilizer Movement in the Soil as Influenced by Nitrogen Rate and Timing in Irrigated Wheat Soil Sci. Soc. Am. J., September 1, 2000; 64(5): 1883 - 1892. [Abstract] [Full Text]