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Rapid recuperation of soil nitrogen following agricultural abandonment in a karst area, southwest China.
- Source :
- Biogeochemistry; Sep2016, Vol. 129 Issue 3, p341-354, 14p
- Publication Year :
- 2016
-
Abstract
- Soil nitrogen (N) dynamics are crucial for ecosystem development and carbon sequestration. However, N dynamics during post-agriculture succession have not been well understood. Here soil N dynamics during post-agriculture succession were investigated in a subtropical karst area, southwest China. The succession sequence includes grassland (~10 years), shrubland (~29 years), secondary forest (~59 years) and primary forest with cropland as reference. The soil is calcareous lithosols. Soil N stock (0-15 cm) in the cropland (335.2 ± 55.1 g N m) was not significantly different from that in the grassland, but was elevated by 120 to 221 % in the later three succession stages. Across the sequence, soil N accumulated with an average rate of 12.4 g N m yr. Soil N stock recovered to the primary forest level in about 67 years following agricultural abandonment. NO concentrations increased while NH concentrations decreased with years following agricultural abandonment. High NO concentrations (66.5-120.9 mg N kg) may imply N saturation in the shrubland, secondary forest and primary forest. Rates of net N mineralization and nitrification increased with succession. δN of soil, leaves and litter was significantly elevated in the later three succession stages relative to the grassland, indicating that the N cycle became more open with succession. N release from bedrock weathering was likely a potential N source in addition to atmospheric N deposition and biological N fixation. Our study suggests that N would not be the limiting nutrient for secondary succession and ecological restoration in the karst region of southwest China. [ABSTRACT FROM AUTHOR]
- Subjects :
- NITROGEN in soils
KARST
CARBON sequestration
ECOSYSTEM dynamics
Subjects
Details
- Language :
- English
- ISSN :
- 01682563
- Volume :
- 129
- Issue :
- 3
- Database :
- Complementary Index
- Journal :
- Biogeochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 117956328
- Full Text :
- https://doi.org/10.1007/s10533-016-0235-3