Influence of nitrogen on atrazine and 2, 4 dichlorophenoxyacetic acid mineralization in blackwater and redwater forested wetland soils

La influencia del nitrógeno en atrazina y la mineralización del acido 2, 4-diclorofenoxiacetico en agua negra y agua roja de suelos húmedos boscosos

Entry, J.A. (1999) Influence of nitrogen on atrazine and 2, 4 dichlorophenoxyacetic acid mineralization in blackwater and redwater forested wetland soils. Biology & Fertility of Soils. 29:348-353.

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Abstract

Microcosms were used to determine the influence
of N additions on active bacterial and fungal
biomass, atrazine and dichlorophenoxyacetic acid (2,4-
D) mineralization at 5, 10 and 15 weeks in soils from
blackwater and redwater wetland forest ecosystems in
the northern Florida Panhandle. Active bacterial and
fungal biomass was determined by staining techniques
combined with direct microscopy. Atrazine and 2,4-D
mineralization were measured radiometrically. Treatments
were: soil type, (blackwater or redwater forested
wetland soils) and N additions (soils amended with the
equivalent of 0, 200 or 400 kg N ha-1 as NH4NO3).
Redwater soils contained higher concentrations of C,
total N, P, K, Ca, Mn, Fe, B and Zn than blackwater
soils. After N addition and 15 weeks of incubation, active
bacterial biomass in redwater soils was lower when
N was added. Active bacterial biomass in blackwater
soils was lower when 400 kg N ha- 1 , but not when
200 kg N ha-1, was added. Active fungal biomass in
blackwater soils was higher when 400 kg N ha-1 , but
not when 200 kg N ha-1, was added. Active fungal biomass
in redwater soils was lower when 200 kg N ha-1 ,
but not when 400 kg N ha-1, was added. After 15 weeks
of incubation 2,4-D degradation was higher in redwater
wetland soils than in blackwater soils. After 10 and 15
weeks of incubation the addition of 200 or 400 kg N
ha-1 decreased both atrazine and 2,4-D degradation in
redwater soils. The addition of 400 kg N ha-1 decreased
2,4-D degradation but not atrazine degradation in
blackwater soils after 10 and 15 weeks of incubation.
High concentrations of N in surface runoff and groundwater
resulting from agricultural operations may have
resulted in the accumulation of N in many wetland
soils. Large amounts of N accumulating in wetlands
may decrease mineralization of toxic agricultural pesticides.

Item Type:	Article
NWISRL Publication Number:	0992
Subjects:	Soil > Chemistry > Nitrogen Mass Import - autoclassified (may be erroneous)
Depositing User:	Dan Stieneke
Date Deposited:	20 Nov 2010 21:54
Last Modified:	17 Nov 2016 15:46
Item ID:	716
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/716