Decomposition of reed leaf and non-leaf litter in the air and on the ground in the Yellow River Delta, China

The decomposition of standing litter is a vital but easily neglected process. Most studies always focused on the decomposition of leaf litter on the surface of soil or sediment, whereas the decomposition of leaf and non-leaf litter in the air is often overlooked. A field experiment was conducted in the Yellow River Delta to investigate the decomposition of leaf and non-leaf (culm and sheath) litter (Phragmites australis) in the air and on the ground. The results showed that the litter on the ground decomposed faster than the standing litter due to its larger enzyme activities, and the remaining mass of litter on the soil surface was 73–87% of the standing litter. The culm litter had the largest mass remaining among three types of litter owing to the lowest enzyme activities and the largest initial C/N and C/P of the culm litter. Concerning the dynamics of nutrient, nitrogen and phosphorus in leaf and non-leaf litter were first released and then enriched at two decomposition interfaces. Of the three types of litter, the culm litter had the highest N remaining after 360 days of decomposition due to the largest initial C/N of the culm litter. Our findings emphasize the importance of standing litter decomposition in the wetlands of the Yellow River Delta, and suggest that the decomposition of non-leaf (culm and sheath) litter of emergent macrophytes should not be ignored in wetlands.