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ARS Home » Research » Publications at this Location » Publication #76950
Title: SYNCHRONY BETWEEN 15N LABELED TROPICAL LEGUME MULCHES AND PLANT N UPTAKE

Author
item GLASENER, K - NORTH CAROLINA STATE UNIV
item WAGGER, M - NORTH CAROLINA STATE UNIV
item MACKOWN, CHARLES

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/3/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Knowledge of the transformations and transfers of N in legume-based agroecosystems is essential for intelligent management of N. Field experiments were conducted to i) quantify the N accumulation of two legumes and determine the relative importance of leaves/stems and roots as sources of N by following N through a legume-soil-multi crop system, and to ii) determine the effectiveness of 15N labeling and rate of 15N assimilation i various plant parts. Desmodium ovalifolium and Pueraria phaseoloides were foliarly labeled with 15N, each 0.5m2 microplot receiving a total of 1/6 g of urea-labeled with 99 atom % 15N at one of 4 rates: 1/6 g x 1 application, 1/12 g x 2, 1/18 g 3, or 1/24 g x 4. In a second study the same two legumes, in 6m2 microplots, were labeled with multiple foliar spray applications of 15N, cut and applied to obtain one microplot containing labeled roots and unlabeled mulch and another microplot containing unlabeled roots and labeled mulch. A corn-rice-corn rotation was then established. Legume/crop tissues and soil were analyzed for 15N. Results from the two studies will provide information on N distribution to legume roots and shoots and relative contributions of plant parts to the N nutrition of succeeding crops, as well as elucidating legume N release dynamics across a corn-rice-corn cropping sequence in terms of plant available N and soil N pools.