US EPA

1575164 

Journal Article 

Effects of NH4+ and NO3- on litter and soil organic carbon decomposition in a Chinese fir plantation forest in South China 

Zhang, W; Wang, S 

2012 

1 

Soil Biology and Biochemistry
ISSN: 0038-0717
EISSN: 1879-3428 

47 

116-122 

10.1016/j.soilbio.2011.12.004 

WOS:000301562600015 

Soil organic carbon (SOC) dynamics and nutrient
availability determine the soil quality and fertility in a Chinese fir plantation forest in
subtropical China. Uniformly C-13-labeled Chinese fir (Cunninghamia lanceolata) and alder (Alnus
cremastogyne) leaf litter with or without 100 mg NH4+ or NO3- were added to the soil. The purpose
was to investigate the influence of N availability on the decomposition of the litter and native
SOC. The production of CO2, the natural abundance of C-13-CO2, and the inorganic N dynamics were
monitored. The results showed that Chinese fir (with a high C:N ratio) and alder (with a low C:N
ratio) leaf litter caused significant positive priming effects (PEs) of 24% and 42%,
respectively, at the end of the experiment (235 d). The PE dynamics showed that positive PE can
last for at least 87 d. However, the possible occurrence of a significant negative PE with a
sufficient incubation period is difficult to confirm. The application of both NH4+ and NO3- was
found to have a stimulating effect on the decomposition of Chinese fir and alder leaf litter in
the early stage (0-15 d) of incubation, but an adverse effect in the late stage. Compared with
NO3-, NH4+ caused a greater decrease in the PE induced by both Chinese fir and alder leaf litter.
The effects of NH4+ and NO3- on the PE dynamics had different patterns for different incubation
stages. This result may indicate that the stability or recalcitrance of SOC, especially in such
plantation forest soils, strongly depends on available leaf litter and application of N to the
soil. (C) 2011 Elsevier Ltd. All rights reserved. 

Inorganic N; C-13-labeled litter; Priming effect; Chinese fir; Soil organic carbon