洪水漫溢对塔里木河中游河岸胡杨林土壤有机碳及活性组分的影响 postprint

Abstract: The ecological water transport of the Tarim River increases flood intensity on both sides of the basin,which has an important effect on the carbon cycle of the riparian Populus euphratica forest ecosystems. Westudied the P. euphratica forest in the middle reaches of the Tarim River and the content changes of organiccarbon and measured and analyzed the active components of the riparian P. euphratica forest at four differentstages (1 m before (W1); 4 days after (W2); 17 days after (W3); and after (W4)). We found that the soil organiccarbon (SOC) content was higher before and after overflow. The effect of flood overflow on the SOC content inthe 0-20 cm soil layer was more significant than that of the 20-100 cm soil layer. During the same stage, theSOC content decreased with soil layer depth. The dissolved organic carbon (DOC) and microbial biomass carbon(MBC) in the 0-10 cm and 40-100 cm soil layers were significantly increased on the 4th day of the overflowcompared to before the overflow. The contents decreased gradually with the extension of the overflow time. Thedifferences between each stage were significant (P < 0.05). The DOC/SOC and MBC/SOC in the same soil layerdiffered significantly as time since the overflow extended (P < 0.05). The extracted organic carbon (EOC) contentin the 0-10 cm soil layer before the overflow was higher than after the overflow. The EOC content in other soillayers during the overflow period was higher than before or after the overflow. The EOC/SOC in the 0-10 cmand 20-60 cm soil layers were significantly different at each overflow stage (P < 0.05). There was a significantlypositive correlation between SOC and DOC content from before the overflow to day 17 of the overflow (r > 0.69,n = 15) and a significantly positive correlation between EOC and DOC content after discharge (r = 0.54, n = 15).There was a significant correlation between SOC and DOC content before the overflow and at various stagesafter the overflow. Based on the above analysis, the flooding process in the middle reaches of the Tarim River hada significant effect on the distribution of SOC and the active components of the riparian poplar forest, withdifferences found in the sensitive soil layers of each component. SOC was most significant in the 0-20 cm soillayer. DOC and MBC were most significant in the 0-10 cm soil layer and the 40-100 cm soil layer, respectively,and EOC was most significant in the 20-60 cm soil layer. Thus, the observed change regularity has the dualcharacteristics of forest and wetland.