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Abstract
Onokpise, O.U.,
J. Moody, K. Outcalt and S.K. Bambo. 2007. Impact of prescribed and
non-prescribed fire treatments on soil nitrogen in the flatwoods of Florida. JEMREST
3:286-303.
DOI: 10.4029/2007jemrest3no129
Prescribed
fire is now considered an important tool for managing forests and forest
ecosystems. However, there is only very limited knowledge available for
understanding the impact of such fire treatments on the soil nutrient
composition of treated forests, particularly the flatwoods of Florida.
Therefore, a study was conducted at the Myakka River State Park (MRSP) in Sarasota, Florida,
to determine the effects of fire treatments on soil nitrogen. The
experimental design was a randomized complete block design with three blocks
and five treatment plots within each block. Soil samples were collected from
randomly selected 50 m x 50 m grid points, before and after prescribed fire
and/or mechanical (mowing and chop) treatments were applied. Samples were
subjected to laboratory analysis for ammonium (NH4+) and nitrate (NO3-) nitrogen
(N) respectively. Results indicated that soil moisture (range of 5 to19%) was
below levels favorable for soil microbial activity immediately after fire
treatments. Prescribed fire favored high production of ammonia nitrogen in
moist locations, while the reverse occurred in dry areas. Higher rates of NO3- nitrogen were obtained from a combination of
fire and mechanical fire fuel treatments. The MRSP exhibited relatively high
carbon to nitrogen (C: N) ratios in the range of 24:1 to 33:1. Thus
prescribed fire as a management tool has little or no negative effects on the
soil N composition of this particular flatwood in Florida.
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