Soil Hydrological Characteristics And Emergy Analysis Of Ecological Benefits Of The Coastal Zone Protection Forest In Qingdao City

The construction of coastal shelterbelt plays an important role in ecological restoration of coastal vulnerable areas,there are many reasons in the construction and later management,such as too high planting density,single tree species selection,lack of tending management,it leads to many problems,such as poor ecological stability of coastal shelterbelt,dominant tree species compressing the living space of other tree species and so on,the overall quality of coastal shelterbelt system is low,the function of ecological service is weak.Therefore,the research on ecological benefits of coastal shelterbelts has received widespread attention.This paper chooses cangma mountain forest farm in Qingdao as the research area,four typical coastal shelterbelt vegetation types,namely Quercus acutissima Carruth.forest（QAC）,Pinus thunbergii Parl.forest（PTP）,Quercus acutissima Carruth.Mixed Pinus thunbergii Parl.forest（QAC×PTP）and Quercus acutissima Carruth.Mixed Robinia pseudoacacia Linn.forest（QAC×RPL）were studied,the method of combining field observation with indoor experiment is adopted,the composition and fractal characteristics of soil particles,soil physical and chemical properties,soil hydrology and litter water holding capacity of the four vegetation types were compared and analyzed;on this basis,based on emergy analysis theory,based on test data,the ecological benefits of coastal zone protection forest in Qingdao city were analyzed by emergy,this study provides a theoretical basis for the allocation and ecological benefit analysis of coastal zone protection forest in Qingdao city,at the same time,it provides a supplement and reference for the theoretical study of emergy analysis of ecological benefits of coastal shelterbelts.（1）The difference of soil particle composition,fractal parameters under four vegetation types varied greatly in the coastal zone protection forest in Qingdao city.The results showed that the soil clay and silt contents of the four vegetation types from large to small were as follows:QAC×RPL mixed forest>QAC×PTP mixed forest>QAC forest>PTP forest,and with the increase of soil depth,the clay and silt contents gradually decreased,while the sand content gradually increased.The single fractal dimension of soil particles in 0～40cm soil layer of four vegetation types in Qingdao cangma mountain forest farm is between 2.30 and2.62,the size follows:QAC×RPL mixed forest>QAC×PTP mixed forest>QAC forest>PTP forest;the single fractal dimension of soil particles in 0～20cm soil layer was larger than that in 20～40cm soil layer;the single fractal dimension of soil particles of four vegetation types has a very significant positive correlation with clay and silt content of soil,and a very significant negative correlation with sand content of soil;the Rényi spectrum of soil particles of four vegetation types in zangmashan forest farm of Qingdao is an inverse S-shaped curve,the capacity dimension is the largest,followed by the information dimension,and the correlation dimension is the smallest,D₀>D₁>D_2;the multiple fractal dimension D₀ of soil particles of four vegetation types has a significant positive correlation with clay and silt content of soil,and a significant negative correlation with sand content of soil.（2）The four vegetation types of the typical coastal zone protection forest in Qingdao city have a good improvement effect on soil physical and chemical properties,and significantly.The soil bulk density of the four vegetation types from large to small was as follows:PTP forest>QAC forest>QAC×PTP mixed forest>QAC×RPL mixed forest,the soil total porosity,capillary porosity and non capillary porosity of the four vegetation types followed the same rule:QAC×RPL mixed forest>QAC×PTP mixed forest>QAC forest>PTP forest;the content of total organic carbon（C）in soil was significantly higher than that of total nitrogen（N）and total phosphorus（P）,the contents of total organic carbon（C）,total nitrogen（N）and total phosphorus（P）in the four vegetation types were as follows:QAC×RPL mixed forest>QAC×PTP mixed forest>QAC forest>PTP forest,the contents of total organic carbon（C）,total nitrogen（N）and total phosphorus（P）decreased with the increase of soil depth.（3）The water-holding performance of four vegetation types litter layer and soil layer was remarkable in coastal zone protection forest in Qingdao city.The accumulation of litter in semi decomposed layer was greater than that in non decomposed layer,the water holding capacity of litter in semi decomposed layer was higher than that in non decomposed layer,the water holding capacity of litter layer of the four vegetation types showed a trend from large to small:QAC forest>QAC×PTP mixed forest>PTP forest>QAC×RPL mixed forest;the maximum soil water holding capacity,capillary water holding capacity and effective water holding capacity of QAC×RPL mixed forest were the highest,PTP forest is the smallest,and it decreases with the increase of soil depth;the steady infiltration rate of soil ranged from 1.42 to3.28 mm·min^-1,the results show that the infiltration capacity of soil is in accordance with the law:QAC×RPL mixed forest>QAC×PTP mixed forest>QAC forest>PTP forest.（4）The results of emergy analysis of ecological benefits of the coastal zone protection forest in Qingdao city showed that:it can be seen that the ecosystem transforms low quality energy into high quality energy,biodiversity conservation accounts for the highest proportion of total emergy.The total emergy flow of the coastal zone protection forest in Qingdao city is 1.19E+22（sej/a）,the input emergy is 4.61E+20（sej/a）,the output emergy is1.14E+22（sej/a）,.The input emergy of renewable resources is 3.50E+20（sej/a）,renewable resource emergy accounts for 2.94%of total emergy,the input emergy of non renewable resources is 1.11E+20（sej/a）,the emergy of non renewable resources accounts for 0.93%of the total emergy.The physical output emergy is 3.23E+21（sej/a）,physical output emergy account for 27.14%of total emergy,the emergy of intangible output is 8.22E+21（sej/a）,the emergy of intangible output accounts for 69.11%of the total emergy,it can be seen that the ecological value of intangible output is the largest,among them,water conservation1.03E+20（sej/a）,soil conservation 7.42E+19（sej/a）,carbon fixation and oxygen release 1.47E+20（sej/a）,forest nutrient fixation 1.91E+20（sej/a）,purification of atmospheric environment 2.16E+21（sej/a）,biodiversity protection 5.55E+21（sej/a）;the emergy analysis shows that biodiversity conservation is an important function of the coastal zone protection forest in Qingdao city,the emergy of ecosystem service function of the coastal zone protection forest in Qingdao city was as follows:Biodiversity Protection>purification of the atmosphere environment>forest nutrient fixation>carbon fixation and oxygen release>water conservation>soil and fertilizer fixation.