Variation behaviour of topsoil trait after fire in the deciduous forest, Yok Don National Park

Abstract

The article evaluated variation behaviour of grass feature, dry carpet,
humus tier, soil erosion and topsoil properties at experiment plots of
controlled fire in the period of 24 months at Yok Don National Park. The
results showed that: the fires had an influence on the characteristics of
vegetation, dry carpet and humus layer. Fire traits have dominated recovery
ability of grass, accumulation of dry carpet after blaze at T5 (after fire 24
months), reaching 80% compared to T0 (before fire). Dry carpet had the
weight and thickness at the time of T5 accumulatively attained 95.4% and
110% as opposed to T0. Amassment of humus tier reached over 100% as
against T0. Fires affected indirectly soil erosion. At the forest stand of 1, 2
and 3, the soil layer was eroded at 4.3 cm, 3.8 cm and 3.5 cm per year
respectively. The total Nitrogen (N), Phosphorus (P) and Potassium (K)
content of the topsoil were affected by blaze and the content of N and P decreased averagely 18.0% ,13.8% while K content averagely increased
21.4% after 24 months. Fires also had a huge impact on digestible Nitrogen
(NH4
+
), Phosphorus (P
2O5) and Potassium (K2O5) content that brought to
the decrease of NH4
+
and P
2O5 content being 27.6% and 28.4%
respectively. Meanwhile, the digestible K2O5 content was transformed and
synthesized better after 24 months with the rise of 44.5%. Apart from fo rest
fire, stand factor had an effect on metabolism and accumulation of NH 4
+
,
P
2O5 and K
2O5. Overall, controlled fires have changed the characteristics of
vegetation, dry carpet, humus tier, erosive intensification and chemical
properties of soil layer. The time for these factors to recover and amass
from 18 to 24 months.