| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Dep. of Crop and Soil Sciences, Washington State Univ., Pullman, WA, 99164-6420
* Corresponding author (Email: pan{at}wsuvml.csc.wsu.edu).
Nitrogen use efficiency (grain weight per unit of N supplied from soil or fertilizer) can be reduced by overfertilization, suboptimal yields, and N losses. Nitrogen is typically fall-applied in eastern Washington for soft white winter wheat (Triticum aestivum L.) production, and is therefore subject to overwinter losses or accumulation in deep soil layers. Increasing grain protein levels of soft white winter wheat have been attributed in part to excessive N application rates and high residual N levels. Spring N applications were evaluated over four site-years as an option to all-fall applied N for reducing N inputs and improving N use efficiency, thereby allowing producers to maintain productivity while controlling grain protein. Five to six N rates ranging from 0 to 140 kg ha–1 for the all-fall N applications were compared with fall-spring split applications of 84 to 140 kg total N ha–1. Nitrogen was applied in the spring by topdressing (TD) or with a spoke-wheel point-injection (PI) system. A 15N experiment was conducted at two locations during the second year to quantify N uptake from fertilizer and soil N. High preplant residual N conditions resulted in limited responses to added N. Nitrogen use efficiency was 26 to 44% lower in the 140 kg ha–1 fall-applied N treatments than in the zero-N control. Reduced N use was related to N losses from the system and to decreased N utilization efficiency (grain weight produced per unit plant N). Spring-applied N, with point injection or topdressing, maintained or increased N use efficiency compared with equivalent all-fall N rates of 84 and 112 kg N ha–l. More 15N-labeled fertilizer (7–16% more) was recovered with a split N application than with fail-applied N at the same total rate of 112 kg N ha–1. At maturity, 68% of plant N was from soil sources with a split application, compared with 80% with an all-fall application. These results suggest spring-N applications with point injection or topdressing can improve fertilizer N recovery and N use efficiency over preplant applications in dryland winter wheat.
Received for publication June 24, 1993.
This article has been cited by other articles:
|
|
 |
|
  B. N. Otteson, M. Mergoum, J. K. Ransom, and B. Schatz Tiller Contribution to Spring Wheat Yield under Varying Seeding and Nitrogen Management Agron. J., February 29, 2008; 100(2): 406 - 413. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Gan, S. S. Malhi, S. Brandt, F. Katepa-Mupondwa, and C. Stevenson Nitrogen Use Efficiency and Nitrogen Uptake of juncea Canola under Diverse Environments Agron. J., February 26, 2008; 100(2): 285 - 295. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Hong, J. G. White, R. Weisz, C. R. Crozier, M. L. Gumpertz, and D. K. Cassel Remote Sensing-Informed Variable-Rate Nitrogen Management of Wheat and Corn: Agronomic and Groundwater Outcomes Agron. J., March 2, 2006; 98(2): 327 - 338. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. W. Woolfolk, W. R. Raun, G. V. Johnson, W. E. Thomason, R. W. Mullen, K. J. Wynn, and K. W. Freeman Influence of Late-Season Foliar Nitrogen Applications on Yield and Grain Nitrogen in Winter Wheat Agron. J., May 1, 2002; 94(3): 429 - 434. [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]
|
|
|
|
 |
|
 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]
|
|
|
|
|
|
A. Limon-Ortega, K. D. Sayre, and C. A. Francis Wheat Nitrogen Use Efficiency in a Bed Planting System in Northwest Mexico Agron. J., March 1, 2000; 92(2): 303 - 308. [Abstract] [Full Text]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| The SCI Journals | Crop Science | Vadose Zone Journal | |||
| Journal of Natural Resources and Life Sciences Education |
Soil Science Society of America Journal | ||||
| Journal of Plant Registrations | Journal of Environmental Quality |
The Plant Genome | |||
