Short-term Effects Of Moso Bamboo Invasion And Logging On Soil Greenhouse Gases Emissions In Chinese Fir Forest

Moso bamboo is a typical clonal plant that can spontaneously expand into the surrounding forests by relying on its powerful bamboo whip without interference.However,the Chinese fir forest is vulnerable to the invasion of moso bamboo due to its single tree species structure,which leads to soil fertility decline.The invasion of moso bamboo affected the growth of Chinese fir.Therefore,the invasion of moso bamboo could be controlled by cutting down moso bamboo to release the growth space of Chinese fir.However,moso bamboo invasion and logging will inevitably change the soil properties of forest land,which will affect soil greenhouse gas emissions.This study takes pure moso bamboo stands,Chinese fir released stands after cutting invaded moso bamboo,mixed stands of moso bamboo and Chinese fir and pure Chinese fir stands as the research objects,greenhouse gas emission flux were quantified with a static chamber-gas chromatography method with 3 replications.To study the short-term effects of moso bamboo invasion and harvesting on soil greenhouse gas emission flux and soil physical and chemical properties of Chinese fir forest;and explore the correlation between soil greenhouse gas emissions and soil indicators.It provides basic data for scientific understanding of the short-term response mechanism of Chinese fir forest soil greenhouse gas emissions to the invasion and logging of moso bamboo,provide theoretical basis for reducing regional greenhouse gas emissions.The main conclusions are as follows:(1)The soil MBC and MBN of the four types of forests all showed seasonal changes in summer and autumn significantly higher than those in winter(p<0.05).After the invasion of moso bamboo,the contents of MBC and MBN in the surface soil gradually decreased with the degree of invasion;the logging of moso bamboo leads to a decrease in the contents of soil MBC and MBN,which is specifically expressed as:CF>MF>RF>BF.(2)The soil inorganic nitrogen content(NH₄⁺-N,NO₃^--N)of the four forests all showed seasonal variation characteristics of high summer and low autumn.The soil NH₄⁺-N and NO₃^--N content increased and decreased with the deepening of moso bambooinvasion.The harvesting of moso bamboo results in a significant increase in soil NH₄⁺-N and NO₃^--N content(p<0.05).(3)Both harvesting and invasion of moso bamboo led to the increase of soil WSOC content.Specific performance:RF>BF>MF>CF,and the difference between the four forest stands is not significant(p>0.05).The seasonal variation of soil WSON in the four stands was consistent,that is,high in summer and low in winter.After the harvesting of moso bamboo,the content of soil WSON in soil increased significantly after moso bamboo logging(p<0.05).The content of WSON in the soil gradually decreases with the deepening of the invasion degree of moso bamboo,and the specific performance was:RF>CF>MF>BF.(4)The soils of the four forests are all represented as soil CO₂ and N₂O emission sources and CH₄ absorption sinks.The emission or absorption flux of the three greenhouse gases presents a consistent seasonal variation pattern with soil temperature and humidity.Compared with CF,moso bamboo harvesting and invasion significantly increase soil CO₂ and N₂O emissions(p<0.05),specifically as follows:BF>RF>MF>CF;For soil CH₄ absorption,the invasion of moso bamboo significantly increases soil CH₄ absorption flux,while moso bamboologging significantly reduces the soil's absorption of atmospheric CH₄(p<0.05),specifically:BF>MF>RF>CF.(5)The soil CO₂ and N₂O emissions are consistent with the correlation performance of soil indicators.Soil temperature,inorganic nitrogen and WSON were the main influencing factors.Soil moisture content and MBN have relatively weak influence on it.However,soil active organic carbon(MBC,WSOC)has no significant effect on soil CO₂ and N₂O emission(p<0.05).(6)Soil temperature,MBC,NO₃^--N and WSON are positively correlated with soil CH₄absorption(p<0.01).Soil MBN and NH₄⁺-N were positively correlated with soil CH₄ absorption(p<0.05);Soil moisture content and soil WSOC had no significant effect on soil CH₄ absorption(p<0.05).(7)In this study area,other scientific forestry measures such as bamboo shoot harvesting can be adopted to prevent the invasion and logging of moso bamboo from,which will increase the greenhouse gas emission flux.