Effects of degradation succession of alpine wetland on soil organic carbon and total nitrogen in the Yellow River source zone, west China

Abstract

Wetland is an important carbon pool, and the degradation of wetlands causes the loss of organic carbon and total nitrogen. This study aims to explore how wetland degradation succession affects soil organic carbon (SOC) and total nitrogen (TN) contents in alpine wetland. A field survey of 180 soil-sampling profiles was conducted in an alpine wetland that has been classified into three degradation succession stages. The SOC and TN contents of soil layers from 0 to 200 cm depth were studied, including their distribution characteristics and the relationship between soil water content (SWC) and microtopography. The results showed that SOC and TN of different degradation succession gradients followed the ranked order of Non Degradation (ND) > Light Degradation (LD) > Heavy Degradation (HD). SWC was positively correlated with SOC and TN (p<0.05). As the degree of degradation succession worsened, SOC and TN became more sensitive to the SWC. Microtopography was closely related to the degree of wetland degradation succession, SWC, SOC and TN, especially in the topsoil (0–30 cm). This result showed that SWC was an important indicator of SOC/TN in alpine wetland. It is highly recommended to strengthen water injection into the wetland as a means of effective restoration to reverse alpine meadow back to marsh alpine wetland.