Five-year changes in soil organic carbon and total nitrogen in coastal wetlands affected by flow-sediment regulation in a Chinese delta

Abstract

Changes in the sources and sinks of soil organic carbon (SOC) and total nitrogen (TN) in wetland soils as indicators of soil quality and climate change have received attention worldwide. Soil samples were collected in 2007 and 2012 in the coastal wetlands of the Yellow River Delta and the SOC and TN were determined to investigate a five-year change in their content and stock in these wetlands as affected by flow-sediment regulation. Our results revealed that the soils in 2007 exhibited greater electrical conductivities, SOC content and density, and ammonium nitrogen (NH4+-N) levels in the top 10 cm soils (p < 0.05) compared with the soils in 2012. In general, the SOC and TN contents decreased with increasing soil depth. However, the highest ratios of soil organic carbon and total nitrogen (molar C/N ratios) were observed in the 30–40 cm soil layer. A significant SOC loss occurred (p < 0.05) in top 10 cm soils, but only a small change in SOC in the top 50 cm soils. Comparatively, TN levels did not show significant differences in the study period.

Ecological stoichiometric characteristics of Carbon (C), Nitrogen (N) and Phosphorus (P) in leaf, root, stem, and soil in four wetland plants communities in Shengjin Lake, China

“…In this study, the highest nutrient concentration of SOC, STN and STP was observed in C.schmidtii and V.natans respectively (Fig.2A, B, C) than the rest two species. This may be related with soil moisture contents as the previous study by (Bonetto et al, 1994; Wang et al, 2016) report indicated. Besides, in our study result, soil moisture (SMC) showed positive linear correlation between, SOC, STN and C: P ratio (Table 2), which can confirm this conclusion and coincide with the above two cited study results.…”

Effect of biochemical fraction of exogenous organic matter on CO2 emission from arid soil

“…However, organic C mineralization in soils causes CO 2 to be released into the atmosphere. In this condition, soil may be considered as a source of a greenhouse gas . Carbon dioxide emission from soil is primarily caused by microbial respiration through the decomposition of soil organic matter .…”

“…In this condition, soil may be considered as a source of a greenhouse gas. 5 Carbon dioxide emission from soil is primarily caused by microbial respiration through the decomposition of soil organic matter. 6 Large amounts of labile C input can directly improve soil microbial respiration.…”

Responses of soil physical, chemical and biochemical properties to short-term impact of tillage in an alfisol under maize (Zea mays L.) cultivation

“…Higher soil microbial populations and enzyme activities associated with SB tillage method compared with the other tillage methods may be related to changes in soil water content, pH, organic C and N levels. Soil moisture acts as the prime factor that stimulate microbial populations; soil pH, organic C and N levels might as well considerably influence the activity of microbes as they have been reported as regulators of this parameter (Subhani et al, 2001; Wang et al, 2016). The water contents of the soil, temperature and aeration regimes, and placement of microbial substrates assist in regulating the ecological niches and types of microorganisms which predominate under each of these tillage treatments (Subhani et al, 2001).…”