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Recovery of Fertilizer Nitrogen Under Field Conditions Using Nitrogen-15

Carter, J.N. and Bennett, O.L. and Pearson, R.W. (1967) Recovery of Fertilizer Nitrogen Under Field Conditions Using Nitrogen-15. Soil Science Society of America Proceedings. 31(1):50-56.

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An experiment was conducted under field conditions to study
the movement and recovery of N15-enriched nitrogen fertilizer
added to soil in the forms of NaNO2 and (NH4)2SO4. The plots
consisted of the soil mass inside cylinders 30 or 60 cm in diameter,
which were pressed into the soil to a depth of 45-60 cm. These
plots were either seeded to sudangrass (sorghum sudanense)
or left uncropped. The plant tops, roots, and the soil, by 15-cm layers, were analyzed for total N and excess N15 content.

Recovery of added N15 from the 32 plots ranged between 96.3
and 101.8%, and averaged 99.0%. There was no significant
difference in recovery of the fertilizer N due to the percent of
excess N15 in the fertilizer, size of plot, exposure to natural
rainfall, cropping, N source, or the time of application of the
fertilizer. Wide variation in recovery of excess N15 occurred with
core sampling and it was found necessary to remove, weigh, mix
and subsample the entire soil mass from within the rims. The
small amounts of unrecovered N were probably due to procedural
errors in the field and laboratory, and leaching and root growth
beyond the sampling zone. There was no indication of any N
loss in the gaseous form.

The fate of applied fertilizer N was followed under field
conditions using N15-enriched nitrogen fertilizer applied to the
soil in situ enclosed by large steel cylinders. Total recovery
of the fertilizer N from these experiments after 8 weeks ranged
from 88 to 96%, but dropped as low as 77% after 10 months.
Recovery of the fertilizer N was greater from an ammonium
source than from nitrate. Better recovery of fertilizer was
obtained when the plots were cropped to sudangrass rather than
left fallow. Doubling the rate of application of the fertilizer N
from 336 to 672 kg/ha did not affect percent of total recovery.
The 4 to 12% of fertilizer N unrecovered after 8 weeks appears
to be due to a loss in the gaseous form, since special precautions
were taken to restrict leaching and to eliminate errors in sampling
and analysis.

Item Type: Article
NWISRL Publication Number: 0067
Subjects: Soil > Amendments > Fertilizer
Mass Import - autoclassified (may be erroneous)
Depositing User: Dan Stieneke
Date Deposited: 20 Nov 2010 21:53
Last Modified: 03 Jan 2017 21:20
Item ID: 517