wAbstract
@In this study, dynamics of dissolved organic matter (DOM) and
mineralization of soil organic C and N in subtropical China were
investigated. Paddy and upland soils were derived from Tertiary
sandstone, Quaternary red clay and river alluvium with low, middle,
and high levels of soil fertility. Dissolved organic carbon contents
(DOC) varied from 3.8 to 68.7 mg/kg and dissolved organic nitrogen
contents (DON) ranged from 2.9 to 18.3 mg/kg, respectively, during
the experimental period. Both DOC and DON increased with increasing
soil fertility. The content of DOM was characterized by strong
seasonal fluctuation in soils, and seasonal patterns showed the
maximum value in Nov and the minimum in July. The contribution
of DOM to mineralization of C and N was significantly affected
by soil types and seasons. DOM removal significantly decreased
the cumulative organic C mineralization in soils derived from
Tertiary sandstone and River alluvium (by 1.6-20.3 with an average
of 7.1), while it did not significantly change those in soils
derived from Quaternary red clay. Similarly, the cumulative mineralization
of
N in paddy soils after DOM removal decreased by 6.7-27.3 over
seasons. In this study, DOM played an important role in soil C
and N mineralization in subtropical China. It appears that contribution
of DOM to mineralization of C and N in paddy soils was possibly
related to DOM content and composition.
Keywords: DOM dynamics; DOM removal; Mineralization of C N; Incubation;
Paddy soils; Subtropical Chinax
1. Introduction
2. Materials and methods
@2.1. Study site and soil collection
@2.2. Experimental methods
@@2.2.1. Removal of soil DOM
@@2.2.2. C mineralization
@@2.2.3. N mineralization
@@2.2.4. Analytic methods
@2.3. Statistic analysis
3. Results and analysis
@3.1. DOM contents among soil types, fertility levels and
seasons
@3.2. Effect of DOM removal on SOC mineralization
@3.3. Effect of DOM removal on SON mineralization
@3.4. Seasonal variation versus DOM removal effects on soil C
and N mineralization
4. Discussions
5. Conclusions
Acknowledgements
References