Residual Nitrate and Mineralizable Soil Nitrogen in Relation to Nitrogen Uptake by Irrigated Sugarbeets

Stanford, George and Carter, J.N. and Westermann, D.T. and Meisinger, J.J. (1977) Residual Nitrate and Mineralizable Soil Nitrogen in Relation to Nitrogen Uptake by Irrigated Sugarbeets. Agronomy Journal. 69(2):303-308.

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Abstract

Previously reported studies on N fertilization of sugarbeets
(Beta vulgaris L.) in southern Idaho revealed considerable
variation among sites in amounts of residual
soil NO₃ and N mineralized during short-term laboratory
incubations. Consequently, the amount of N fertilizer
needed to achieve near-maximum yields of sucrose differed
markedly. The purpose of this study was to determine
the feasibility of estimating amounts of N mineralized
in the root zone during the season, taking into
account site variations in temperature and soil water
regimes. Residual soil NO₃--N and mineralizable N to
approximate rooting depth were estimated for 21 field
sites in 1971 and six sites in 1972. The relative contributions
of these two N sources to total N uptake by the
crop, in the absence of applied fertilizer N, were then
assessed. Estimates of N mineralized in the upper 45-
cm soil layer for each successive month, ∆N, over a 6-
month period were derived using the expression, ∆N/
∆t kWN (k = fraction of N mineralized during each
month, ∆t, adjusted for average air temperature; and W
the estimated soil water content expressed as a fraction
of the available water storage capacity). Resulting
estimates of the fraction of potentially mineralizable N
converted to (NO₃- + NH₄+)-N between 1 April and
30 September ranged from 0.15 to 0.22 (mean ± S.D. =
0.18 ± 0.02) in 1971 and 1972. On the average, mature
sugarbeets recovered about 73% of the estimated N mineralized
(6 months) plus residual NO₃--N. The relative
contributions of these two sources of soil derived N, respectively,
were approximately 66 and 75%, as estimated
from multiple regression analyses.

Item Type:	Article
NWISRL Publication Number:	0397
Subjects:	Irrigated crops > Sugarbeet Soil > Chemistry > Nitrogen Mass Import - autoclassified (may be erroneous)
Depositing User:	Dan Stieneke
Date Deposited:	20 Nov 2010 21:51
Last Modified:	02 Feb 2017 17:47
Item ID:	334
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/334