Nitrogen use efficiency and nitrogen budget for conservation tilled wheat

Journal Article · · Soil Science Society of America Journal; (USA)

DOI:https://doi.org/10.2136/sssaj1988.03615995005200050035x· OSTI ID:5644727

Sharpe, R R; Harper, L A; Giddens, J E; Langdale, G W ^[1]

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1. USDA-ARS, Byron, GA (USA)

The objectives of this study were to determine the relative uptake rates of residual soil N and fertilizer N in conservation tilled winter wheat. These data were combined with soil mineralization and aerial NH{sub 3} flux data to present a N budget for the soil-plant-atmosphere system. Fertilizer N uptake was determined using ammonium nitrate tagged with 3.78 atomic % {sup 15}N. Fertilizer N uptake and N mineralization rates were determined four times during the spring growing season. Amounts of NH{sub 4} and NO{sub 3} in the top 0- to 300-mm soil layers were determined biweekly. Fertilizer N levels in the surface to 75-mm soil layers decreased rapidly due to plant uptake and immobilization. Of the N fertilizer utilized by the plants, 61% was absorbed in the first 28 d after application. During early vegetative growth stages, fertilizer N uptake was 1.33 kg ha{sup {minus}1} d{sup {minus}1}. After 4 to 5 wk, mineralization of fertilizer N became apparent and fertilizer N uptake rates increased until harvest. Influx of atmospheric N was small but total NH{sub 3} efflux from the soil-plant system was 15.5 kg N ha{sup {minus}1}. About 21% of the spring applied fertilizer N was lost through NH{sub 3} volatilization and losses of this magnitude need to be considered in N balance studies. Placement of fertilizer N below the surface soil layer may decrease immobilization and increase plant uptake of N.

• OSTI ID: 5644727
• Journal Information: Soil Science Society of America Journal; (USA), Journal Name: Soil Science Society of America Journal; (USA) Vol. 52:5; ISSN SSSJD; ISSN 0361-5995
• Country of Publication: United States
• Language: English

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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
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