Study On Ecological Benefits Of 5 Kinds Of Ecological Public Welfare Forests

This study was conducted in 5 forests?broadleaved forests of Zeilaokeng,Baishigang and Xianrenchun,and coniferous and broadleaved mixed forests of Dadiaoekeng and Baishigang?in the Yunyong forest farm of Foshan,Guangdong.The nutrient content,specific leaf area,photosynthetic characteristics,chlorophyll fluorescence parameters ofleaves,litter,understory plant diversity,soil physical properties and biochemistries were determined.The aim of this study was to provide theoretical basis for the cultivation and maintenance management of ecological forest.The results were as follows:For 5 ecological forests,the soil bulk density,total soil porosity,p H ranged from 1.03to1.32 g·cm^-3,49.91 to 60.97%,and 4.21 to 4.45,respectively.Soil organic matter content ranged from 17.69 to 34.46 g·kg^-1,and contents of total N,total P,total K,total Ca,total Mg ranged from 0.73 to 1.26 g·kg^-1,0.183 to 0.25g·kg^-1,8.58 to 23.91g·kg^-1,91.33 to333.16 mg·kg^-1 and 431.69 to 712.22 mg·kg^-1,respectively.Soil contents of Alkali hydrolyzable nitrogen,available P,available K,exchangeable Ca and exchangeable Mg ranged from 74.34 to 109.65,0.16 to 8.79,29.19 to 53.62,20.28 to 54.41 and 6.35 to 8.85mg·kg^-1,in respectively.Activities of soil catalase,acid phosphatase and urease ranged from 2.17 to 3.31 g·mL^-1,367.13 to 935.48mg·kg^-1 and 452.13 to 566.75 mg·kg^-1,respectively.The number of bacteria,fungi and actinomycetes in the soil ranged from 3.04to 10.76×10⁵,1.97 to 20.98×10² and 5.02 to 46.71×10³ g^-1,respectively.The contents N,P,K Ca and Mg of the main plants of the Zailaokeng were 14.25g·kg^-1,0.56 g·kg^-1,7.71 g·kg^-112.12 g·kg^-1and 0.95 g·kg^-1,respectively;whereas N content of coniferous and broadleaved mixed forest of Dadiaokeng,Baishigang,broadleaved forest of Baishigang and Xianrenchun ranged from 16.51 to 21.71,15.51 to 22.87,12.17 to17.62and 14.49 to 38.18 g·kg^-1,respectively;their P content ranged from 1.08 to 1.14,0.90 to 1.45,0.63 to 0.97and 0.56 to 1.82 g·kg^-1,respectively,K content ranged from 11.87to 18.90,7.26 to 25.87,4.48 to 17.41and 7.12 to 24.45 g·kg^-1,respectively;Ca content 4.20to 8.09,5.22 to 10.65,4.60 to 9.08and 1.43 to 5.67 g·kg^-1,respectively;Mg content ranged from 1.54 to 1.94,0.51 to 2.09,0.68 to 1.81and 0.61 to 1.09 g·kg^-1,respectively.Among the leaf SPAD of main trees was 60.21 in b roadleaved forests of Zeilaokeng,and that ranged 41.24 to 54.56,34.07 to 45.84,38.66 to 50.83 and 39.85 to 43.55inconiferous and broadleaved mixed forests of Dadiaoekeng and coniferous and broadleaved mixed forests of Baishigang,and broadleaved mixed forests of Baishigang and broadleaved mixed forests of Xianrenchun,respectively.The net photosynthetic rate?P_n?of the main plants was 2.23?mol·m^-2·s^-1in broadleaved forests of Zeilaokeng,and that ranged from 2.19 to 5.89,4.01 to 9.28,4.05 to9.04and 3.67 to 5.38?mol·m^-2·s^-1 inconiferous and broadleaved mixed forests of Dadiaoekeng and coniferous and broadleaved mixed forests of Baishigang,and broadleaved mixed forests of Baishigang and broadleaved mixed forests of Xianrenchun,respectively.Maximum fluorescence parameters?F_m?of the main plants in broadleaved forests of Zeilaokeng was 332.25,and that ranged from 267.10 to 305.25,273.00 to 331.25 241.00 to327.33and 304.00 to 342.00 in coniferous and broadleaved mixed forests of Dadiaoekeng and coniferous and broadleaved mixed forests of Baishigang,and broadleaved mixed forests of Baishigang and broadleaved mixed forests of Xianrenchun,respectively.Litter storage and maximum water holding capacity ranged from 11.82 to15.22kg·m^-2and 23 to 111%in 5 kinds of ecological forest,respectively,and content of litter N,P and K ranged from11.82 to 15.22,0.38 to 0.59 and 0.93 to 3.39 g·kg^-1,respectively.Simpson index,Shannon-Wiener diversity index,Evenness index J_swand J_siranged from0.5 to 0.79,0.69 to 1.60,0.26 to 0.62 and 0.62 to 1.79 in shrub layer and ranged from0.61 to 0.84,1.07 to 2.03,0.28 to 0.38and 0.76 to 0.97 in the herb layer in the five forests,respectively.Correlation analysis indicated thatsignificant correlationsexistedbetweensoil physical properties and nutrient,betweensoil nutrient and enzyme,betweensoil nutrient and litter nutrient,betweensoil nutrient and microorganism number,betweensoil enzyme and microorganism number,betweenlitter nutrient and microorganism number,between specific leaf area and leaf nutrient,soil nutrients as well astree leaf nutrient,betweensoil enzyme and tree leaf nutrient.There were significant correlations between net photosynthetic rate and leaf nutrients,fluorescence,specific leaf area and leaf SPAD of trees.