Field measurements of N-utilization efficiency and nitrate movement in soils using $sup 15$N-depleted fertilizer

Conference · Wed Jan 01 04:00:00 EST 1975

OSTI ID:4155390

Broadbent, F E

A field experiment consisting of 48 plots on Yolo fine sandy loam was set up with 4 levels of fertilizer, 0, 90, 180, and 360 kg N/ha applied as (NH$sub 4$$)$$sub 2$SO$sub 4$ containing less than 0.003 at. percent $sup 15$N. Three irrigation regimes equivalent to 1/3, 3/3, and 5/3 of the normal evapotranspiration (ET) curves for maize at this location were used. Isotopic composition of components of the maize crop was very uniform at a given fertilizer level. Efficiency of fertilizer N uptake by the crop ranged from 33 percent at the 360 kg level to 53 percent at the 90 kg level. Analysis of soil solutions at various depths in the soil over the season showed that very little fertilizer-derived nitrate moved below the root zone unless both fertilizer level and amount of water applied was excessive. (auth)

• Research Organization: Univ. of California, Davis
• NSA Number: NSA-33-007650
• OSTI ID: 4155390
• Country of Publication: IAEA
• Language: English

Related Subjects

*FERTILIZERS
*MAIZE
*NITRATES-- DIFFUSION
*NITROGEN 15-- UPTAKE
*SOILS
551201*
AGRICULTURE
EFFICIENCY
N48830* --Life Sciences--New Tracer Techniques--Other