Decomposition and return of C and N of plant litters of Phragmites australis and Suaeda salsa in typical wetlands of the Yellow River Delta, China

Abstract

Litter decomposition is the key process of nutrient cycling and energy flowing in wetlands, which is also one of the important processes to maintain wetland ecosystem functions. The litter decomposition and C and N returns of Phragmites australis and Suaeda salsa were investigated during the growing period in typical wetlands f the Yellow River Delta with different flooding frequencies using litter bag technique in order to study the effects of flooding frequencies on litter decomposition and nutrient return of wetland plants. The results showed that during the study period, the litter weight loss rate and C return rate of Phragmites australis were lower than those of Suaeda salsa, while N return rate (64.3%) was higher compared to Suaeda salsa(43.3%) under the same flooding patterns. Flooding frequency had a significant effect on the processes of litter decomposition and nutrients returns of Phragmites australis and Suaeda salsa. Seasonally-flooded Phragmites australis had the highest decomposition rate, but the tidally-flooded Phragmites australis had a higher N return rate. However, the C return rate of the short-term-flooded Phragmites australis showed higher values in respective to others. Suaeda salsa had higher return rates of C and N elements and weight loss rate in tidally flooded wetlands than those in in short-term-flooded wetlands.