Effects Of Different Plantation Stands On Soil Physical And Chemical Properties In Rocky Desertification Area Oleifera

The artificial forest planted for rocky desertification control in Southwest China has gradually entered the middle-aged forest stage now.Mastering the influence law of different artificial forest stands on soil physical and chemical properties in rocky desertification area is the prerequisite for formulating forest cultivation,forest renewal and forest sustainable utilization in rocky desertification area.In this study,12 near mature forest stands(Michelia maudiae Dunn,Lindera megaphylla Hemsl.,Liriodendron chinense(Hemsl.)Sargent.,Metasequoia glyptostroboides Hu&W.C.Cheng,Cinnamomum septentrionale Hand.-Mazz,Nyssa sinensis Oliv.,Choerospondiasaxillaris(Roxb.)Burtt et Hill.Corylus chinensis Franch.,Cupressus lusitanica Mill.Quercus acutissima Carruth.,Taiwaniacryptomerioides,Kalopanaxseptemlobus(Thunb.)Koidz.)and two types of comparison plots under the same site conditions in the national long-term scientific research base for comprehensive control of rocky desertification in Wuling Mountain were selected as the research objects,set the sample plot of each forest land as 20m ×20m and repeat it for 3 times,and the forest vegetation in the standard plot was comprehensively investigated,Stratified sampling was carried out on the soil of various forest stands,and the chemical and physical properties were measured.Through R language programming,mathematical analysis methods such as analysis of variance,cluster analysis and correlation analysis were used to analyze the total N of surface(0-15cm)soil samples of different plantations,the total Ca,total P,total Mg and total K of multi-layer mixed soil samples,as well as The contents of total Ca,total P and total Mg in soil at different depths of four plantation species of Nyssa sinensis Oliv.,Quercus acutissima Carruth.,Liriodendron chinense(Hemsl.)Sargent.,Choerospondiasaxillaris(Roxb.)Burtt et Hill.were comprehensively analyzed and studied.The results are as follows:(1)The plantation can promote the accumulation of total N content in topsoil.The soil total N content of different tree species is significantly different.Choerospondiasaxillaris(Roxb.)Burtt et Hill.(3.53g/kg)>Nyssa sinensis Oliv.(3.38g/kg)>Quercus acutissima Carruth.(3.26g/kg)>Corylus chinensis Franch.(3.07g/kg)>Micheliamaudiae Dun(2.90g/kg)>Liriodendron chinense(Hemsl.)Sargent.(2.76g/kg)>Kalopanaxseptemlobus(Thunb.)Koidz.(2.34g/kg)>Cinnamomum septentrionale Hand.Mazz(2.32g/kg)>Lindera megaphylla Hemsl.(2.27g/kg)>Cupressus lusitanica Mill.(2.23g/kg)>Taiwaniacryptomerioides(2.07g/kg)>Metasequoia glyptostroboides Hu&W.C.Cheng(1.45g/kg)The law of soil total N content is deciduous broad-leaved tree species>evergreen broad-leaved tree species>coniferous tree species.(2)The plantation had a decreasing effect on the content of total P in each layer of soil.The total P content of soil in each layer of plantation is mostly lower than that in each layer of wasteland,especially in the stands of Cupressus lusitanica Mill.,Cinnamomum septentrionale Hand.-Mazz,Kalopanaxseptemlobus(Thunb.)Koidz.The artificial forest can promote the total K content of each layer of soil,and there is a significant difference in the total K content of each layer of each forest,such as Quercus acutissima Carruth.(5.59g/kg)>Metasequoia glyptostroboides Hu&W.C.Cheng(5.06g/kg)>Liriodendron chinense(Hemsl.)Sargent.mixed forest(4.94g/kg)>Corylus chinensis Franch.(4.75g/kg)>Choerospondiasaxillaris(Roxb.)Burtt et Hill.(4.48g/kg)>Kalopanaxseptemlobus(Thunb.)Koidz.-1(3.85g/kg)>wasteland(3.36g/kg).The total Ca content of soil in each layer of most plantation was significantly higher than that in each layer of wasteland,Corylus chinensis Franch,Nyssa sinensis Oliv.and Quercus acutissima Carruth.are calcium rich,and the soils of Cupressus lusitan-ica Mill.,Kalopanaxseptemlobus(Thunb.)Koidz.and Cinnamomum septentrionale Hand.-Mazz stand are calcium deficient The total Mg content of soil in each layer of most plantation was significantly lower than that in wasteland.(3)There were significant differences in the contents of total P,Ca and Mg in different soil layers of four different plantations.According to the analysis of total P,Ca and Mg nutrient contents in the soil between each soil layer of the four plantations,each tree species has its own characteristics:Nyssa sinensis Oliv.is rich in calcium,Quercus acutissima Carruth.is slow in phosphorus,calcium and magnesium,Liriodendron chinense(Hemsl.)Sargent.is rich in phosphorus and magnesium,and Choerospondiasaxillaris(Roxb.)Burtt et Hill.is rich in phosphorus and magnesium.(4)Different plantations can promote soil physical properties,improve soil pore structure,water storage capacity and permeability.(5)Soil quality water content was significantly negatively correlated with soil bulk density,extremely positively correlated with maximum water holding capacity,capillary water holding capacity,field water holding capacity and capillary porosity,and significantly positively correlated with non capillary porosity.In this paper,the experimental results were systematically analyzed and discussed from the aspects of the impact of various afforestation tree species on soil physical and chemical properties and the cultivation and management measures of artificial forests in rocky desertification areas.