The Ground Litter Decomposition In Different Components Of Phragmites Australis And Influence Factors In Minjiang River Estuary

Phragmites australis is one of the dominant species in the Minjiang estuary,the ground litter decomposition in different components of Phragmites australis have an great influence on the formation and evolution of soil organic matter.The decomposition were measured using the mesh bags methords, laboratory experiment, molybdenum antimony colorimetry to study the different components of Phragmites australis litter decomposition characteristics and affecting factors.Results of this study are as follows:(1) The ground litter decomposition in different components of Phragmites australis at different rates, leaf Phragmites australis:0.0067 d-1> inflorescence Phragmites australis: 0.0064 d-1> 80-130 cm stem Phragmites australis:0.0035 d-1>130-180 cm stem Phragm ites australis:0.0029 d-1>30-80 cm stem Phragmites australis:0.0028 d-1>0-30 cm stem Phragmites australis:0.0019 d-1(2) The ground litter decomposition in different components of Phragmites australis have different decomposition rates in different stages of decomposition, lodging stages of deco mposition rate significantly greater than standing dead phase.(3) The ground different components of Phragmites australis litter in carbon concentra tion showed different trends, the different components of litter in a net release of carbon elements (NAI<100%).(4) The ground different components of Phragmites australis litter in nitrogen concentra tions showed fluctuated changes, in terminal phase of experiment, the nitrogen con ce ntr ation of litter has excessed its initial concentration, other components have occurred in the nitrogen release (NAI<100%), besides the litter of 0-30 cm stem Phragmites australis and 30-80 cm stem Phragmites australis occurred nitrogen accumu lation,(5) The ground different components of Phragmites australis litter in phosphorus concen tration showed different trends, after the decomposition of 15 days, showed a rapidly decrease of phosphorus concentration, NAI coefficient showed that have occurred in the release of phosphorus elements (NAI<100%).(6) During the early stage of litter decomposition, the losing of different element in different ways, the losing of carbon element by mineralization, the losing of nitrogen and phosphorus element by leaching.(7) The ground litter decomposition rate in different components of Phragmites australis was significantly negatively correlation with the C/N, it was negatively correlation with N/P,C/P.(8) The higher concentration of nitrogen and phosphorus inputing inhibited the rate decomposition of Phragmites australis litter.(9) The ground litter decomposition rate in different components of Phragmites australis was significantly positive correlation with soil temperature, air temperature, tidal temperature, tidal salinity, it was significantly negatively correlation with the level of tide water, the average wind speed.(10) The decomposition of litter have influence on soil temperature,soil salinity,soil pH, but there was no significant difference.