In forest ecosystems, litter is an important source of organic matter that can alter soil physiochemical characteristics, microbial activities, and biomass. Tropical rainforest soils are considered a major source of atmospheric N2O. But few studies have reported the effect of the amount of litter on N2O emissions from tropical rain forests.
Researchers from Xishuangbanna Tropical Botanical Garden (XTBG) conducted a study to evaluate the effects of litter input and followed decomposition process on soil–atmosphere N2O fluxes. They aimed to quantify the contribution of litter to N2O effluxes. They further wanted to determine whether litter inputs, the decomposition process, soil, or climate were important controls on soil N2O efflux in Xishuangbanna tropical rainforest in SW China.
The researchers followed a paired study with a control treatment and a litter-removed treatment for two years, continuously monitoring the effects of these treatments on soil N2O efflux, fresh litter input, decomposed litter carbon and nitrogen, soil nitrate, ammonium , dissolved organic carbon), and dissolved nitrogen.
They found that the soil N2O efflux and litter contribution seasonally varied. There was a clear seasonal pattern in the contribution of the litter input to the soil N2O efflux in the Xishuangbanna tropical rainforest. Litter removal significantly reduced the soil-atmosphere N2O efflux.
Although the biomass of the litter input was the most important contributor to surface emissions of N2O, the combination of litter, soil, and climatic factors also influenced the litter contribution to N2O emissions both in Xishuangbanna forest
They also found that litter carbon input through decomposition process was the dominant factor regulating the soil–atmosphere N2O efflux, litter removal may influence not only the N2O emission dynamics but also the N2O emission mechanisms.