| This experiment used four typical artificial young forests(Pinus tabuliformis forests,Pinus bungeana forests,Fraxinus chinensis forests and Sophora japonica forests)of Beijing Daxing district which were newly built as research objects to analyze the changes of soil physical and chemical properties before and after application of organic compound fertilizer.The soil fertility evaluation was carried out by the modified Nemero index method.In addition,the growth of forest trees,leaf nutrient content,chlorophyll content,leaf area,leaf dry weight and leaf water content were measured and compared to study the fertilization effects and to explore the efficient and economical amount of fertilizers.The main conclusions are as follows:(1)After applying different concentrations of organic compound fertilizer,the changes of soil physical and chemical properties of Pinus tabulaeformis forest and Pinus bungeana forest showed similarity.The effects of 30kg per plant fertilization treatment on improving the soil bulk density,field water holding capacity,soil capillary water holding capacity,soil total porosity,soil total nitrogen,soil available potassium and the soil organic matter content of Pinus tabulaeformis forests and Pinus bungeana forests were the best.25kg per plant fertilization treatment was more suitable for improving the soil available phosphorus content.20kg per plant fertilization treatment could improve the soil alkalinity well.However,the changes of soil physical and chemical properties of Pinus tabulaeformis forests and Pinus bungeana forests also showed different characteristics.The effects of 25kg per plant fertilization treatment was the best to improve the soil saturated water content of Pinus tabulaeformis forest,while the Pinus bungeana forests had the highest soil saturated water content under the treatment of 30kg per plant fertilization concentration.(2)The fertilization treatment of 20kg per plant had a significant effect on increasing the field water holding capacity of the Fraxinus chinensis forests in 0?20cm soil layer,while 25kg per plant fertilization treatment was more suitable to increase the soil saturated water content,soil total porosity and the soil available potassium content in 0?20cm soil layer,soil water holding capacity in 20?40cm soil layer,and to reduce the soil bulk density.The fertilization treatment of 30kg per plant in the Fraxinus chinensis forests had a good effect on reducing soil alkalinity and improving the soil capillary water holding capacity,soil total nitrogen content,soil organic matter and soil saturated water content.soil total porosity and soil available potassium content in 20?40cm soil layer(3)The improvement effects of the soil bulk density,soil water holding capacity,soil saturated water content,soil capillary water holding capacity,soil total porosity and soil total nitrogen content in the Sophora japonica forests were the best under the fertilization treatment of 20kg per plant.The fertilization treatment of 30kg per plant had good effects on the soil pH value improvement in 0-20cm soil layer,and the content of soil available phosphorus,soil available potassium and soil organic matter under that fertilization concentration was the highest in the Sophora japonica forests.Besides,the fertilization treatment of 25kg per plant was more suitable for improving the soil alkalinity in 20?40cm soil layer(4)According to the soil fertility evaluation based on the modified Nemero index method,the soil fertility of 0?20cm soil layer is better than that of 20?40cm soil layer in general.The soil organic matter content of Pinus tabulaeformis forests were the lowest.Under the fertilization treatment of 30kg per plant,the soil fertility of that forests was the highest.The soil available potassium content of Pinus bungeana forests was the lowest,which needed to be paid attention to.The Pinus bungeana forests had the highest soil fertility under the fertilization treatment of 30kg per plant in 0?20 cm soil layer,while the highest fertility in the 20?40 cm soil layer appeared under the fertilization treatment of 25kg per plant.The soil organic matter of the Fraxinus chinensis forests was the lowest,and it should be artificially supplemented with organic matter.In 0?20cm soil layer,the soil fertility of the Fraxinus chinensis forests was the highest under the fertilization treatment of 20kg per plant while the fertilization treatment of 30kg per plant was more suitable to improve soil fertility in 20?40 cm soil layer.The soil available phosphorus content of the Sophora japonica forests was the lowest so that phosphorus should be supplemented with for direct absorption of trees.in 0?20cm soil layer,the fertilization treatment of 30kg per plant in the Sophora japonica forests was more conducive to improving the soil fertility,while the soil fertility in the 20?40cm soil layer under the fertility treatment of 20kg per plant was the highest.(5)Under the fertilization treatment of 25kg per plant,the height and diameter at breast height of the Pinus tabulaeformis forests was higher than other fertilization treatment.The fertilization treatment of 30kg per plant was more conducive to the cultivation of high-quality Pinus bungeana,but the fertilization treatment of 25kg per plant was more economical to promote the growth of the base diameter and the height under the premise of ensuring better growth of the forests.The fertilization treatment of 30kg per plant had the best effects on promoting the height and diameter at breast height growth of the Fraxinus chinensis forests.The fertilization treatment of 30kg per plant was conducive to the growth of the diameter at breast height in the Sophora japonica forests,while the fertilization treatment of 25kg per plant had a good effect on the height growth of that forests.(6)The fertilization treatment of 25kg per plant was more suitable for supplementing the nitrogen elements required for the growth of the Pinus tabulaeformis forests in the summer,and the fertilization treatment of 30kg per plant was more conducive to preventing the nitrogen 'nutrient dilution' in the late autumn of the Pinus tabulaeformis forests.The fertilization treatment of 30kg per plant had better effects on providing the phosphorus and potassium elements of the Pinus tabulaeformis forests.The fertilization treatment of 25kg per plant could better supplement the nitrogen and phosphorus elements required during the whole growth period of the Pinus bungeana forests,which was more effective on providing the potassium in the autumn.The fertilization treatment of 30kg per plant was more conducive to improving the potassium content of the Pinus bungeana forests in the summer.The fertilization treatment of 25kg per plant was more suitable for supplementing the nitrogen and phosphorus required for the growth,while the fertilization treatment of 30kg per plant had better effects on providing the potassium during the whole growth period and phosphorus needed in the autumn to the Fraxinus chinensis forests.For the Sophora japonica forests,the fertilization treatment of 30kg per plant was better for supplementing the total nitrogen,total potassium during the growth and providing the phosphorus content of the leaves required in the summer,while the fertilization treatment of 25kg per plant was more suitable for increasing phosphorus required in the late autumn.(7)For the Pinus tabulaeformis forests and the Pinus bungeana forests,the fertilization treatment of 25kg per plant had the highest content of the chlorophyll a,chlorophyll b and total chlorophyll,while the fertilization treatment of 30kg per plant fertilization could improve those of the Fraxinus chinensis forests and the Sophora japonica forests.(8)The fertilization treatment of 25kg per plant was more suitable for increasing leaf area,leaf dry weight and leaf water content of the Pinus tabulaeformis forests and the Pinus bungeana forests,while the fertilization treatment of 30kg per plant was better for increasing leaf area,leaf dry weight and leaf water content of the Fraxinus chinensis forests and the Sophora japonicu forests. |
PDF Full Text Request