Effects Of Economic Forest Development And Cultivation On Soil Hydrophysical Properties In Ta-pieh Mountain Area

In order to explore the influence of economic forest development and cultivation methods on the hydro-physical properties of forest soils in hilly areas,sample plots were set up in Jinzhai County,Dabie Mountain Province,Anhui Province,with chestnut and oil tea economic forest soils as the target,and the changes of hydro-physical properties of economic forest soils under different development and cultivation methods were investigated using soil in situ tests,sample tests and simulation analysis.The sample plots of different development and cultivation(management)methods of chestnut forest were set up as downhill cultivated chestnut forest(PBL),chestnut-tea intercropped chestnut forest(JBL),and abandoned cultivated restored chestnut forest(ZBL),with ecological forest(STL)as the control.The sample plots of different development and cultivation(land preparation)methods of oil tea forest were set up as PYC and TYC,and the oil tea forest was developed from abandoned and restored chestnut forest(ZBL),and this forest was used as the control.The tests were analyzed for soil infiltration,mechanical composition,agglomerates,porosity and soil organic matter in the different sites.Main findings and conclusions.1.Soil hydro-physical properties in chestnut forests under different development and cultivation(management)methodsThe hydro-physical properties of the soil in the forest were significantly lower in the PBL compared to the STL.The main characteristic indicators are as follows(0-20 cm soil layer):the content of clay-powder particles decreases(6.79%),the content of sand particles increases(10.75%),the soil particle-size dimension D decreases(1.70%),the soil mechanical composition becomes coarser;the large mechanical stable aggregate R_0.25(m)and large water stable aggregates R_0.25(w)decreases(8.28%and 8.53%),mechanical stable man weight diameter MWD_mand water stable man weight diameter MWD_wbecame smaller(13.79%and11.11%),the degree of soil agglomeration and stability decreased;the total porosity?_t,capillary porosity?_cand non-capillary porosity?_nbecame smaller(10.63%,12.77%and6.24%)in soil pore composition,and the total pore water storage W_t,capillary pore water storage W_cand non-capillary pore water storage W_nbecame smaller.W_t,W_cand W_ndecreased(10.63%,12.77%,and 6.24%),and the initial and steady infiltration rates?₀and?_cdecreased(29.17%and 52.92%).The hydro-physical properties of the forest soil were significantly improved in the ZBL compared to the PBL.The main characteristic indicators were(0-20 cm soil layer):the content of clayey powder particles increased(7.70%),the content of sand particles decreased(10.27%),and D increased(1.84%),the soil mechanical composition became finer;the soil R_0.25(m)and R_0.25(w)increased(6.63%and 9.11%),MWD_mand MWD_wbecame larger(13.76%and 12.71%),the degree of soil agglomeration and stability increased;?_t,?_cand?_nincreased in soil pore composition(7.75%,10.08%and 3.33%),soil W_t,W_cand W_nincreased(7.75%,10.08%and 3.33%%);?₀and?_cincreased in soil infiltration properties(34.93%and 83.33%).The soil hydro-physical properties of JBL were also significantly higher than those of down-slope PBL,but lower than those of ZBL.2.Soil hydro-physical properties of oil tea forests under different development and cultivation(land preparation)methodsThe soil hydro-physical properties of the stands were reduced after the ZBL were developed into oil tea stands.And the soil hydro-physical properties of the stand under both development cultivation(land preparation)methods were better in the TYC than in the PYC.The main characterization indicators of soil hydro-physical properties of TYC compared to PYC are reflected in(%change in soil size from 0 to 20 cm):higher clay-powder particle content(12.62%),smaller sand particle content(14.28%),and larger soil D(3.94%),finer soil mechanical composition;higher soil R_0.25(w)(1.11%),larger MWD_w(1.77%),higher degree of soil agglomeration and stability;larger?_tand?_c(3.27%and 4.33%)and higher soil W_tand W_c(3.27%and 4.33%)in soil pore composition;and larger?₀and?_c(5.27%and 17.29%)in soil infiltration properties.3.Soil infiltration process model simulation and infiltration rate influence factor correlation analysisSoil infiltration model(Philip,Kostiakov,Kostiakov-lewis,Horton model)was used to fit the infiltration observation data,which showed that Horton model was more suitable for simulating soil infiltration process and characteristic parameters(?₀and?_c)of economic forest land under different development and cultivation methods.The correlation analysis of soil infiltration rate influencing factors showed that soil?_cwas significantly positively correlated with soil porosity(?_t,?_cand?_n),soil R_0.25(m)and R_0.25(w),and soil organic matter content,and negatively correlated with soil bulk density.