Background:Large-scale afforestation can significantly change the ground cover and soil physicochemical properties,especially the soil fertility maintenance and water conservation functions of artificial forests,which...Background:Large-scale afforestation can significantly change the ground cover and soil physicochemical properties,especially the soil fertility maintenance and water conservation functions of artificial forests,which are very important in semi-arid mountain ecosystems.However,how different tree species affect soil nutrients and soil physicochemical properties after afforestation,and which is the best plantation species for improving soil fertility and water conservation functions remain largely unknown.Methods:This study investigated the soil nutrient contents of three different plantations(Larix principis-rupprechtii,Picea crassifolia,Pinus tabuliformis),soils and plant-soil feedbacks,as well as the interactions between soil physicochemical properties.Results:The results revealed that the leaves and litter layers strongly influenced soil nutrient availability through biogeochemical processes:P.tabuliformis had higher organic carbon,ratio of organic carbon to total nitrogen(C:N)and organic carbon to total phosphorus(C:P)in the leaves and litter layers than L.principis-rupprechtii or P.crassifolia,suggesting that higher C:N and C:P hindered litter decomposition.As a result,the L.principis-rupprechtii and P.crassifolia plantation forests significantly improved soil nutrients and clay components,compared with the P.tabuliformis plantation forest.Furthermore,the L.principis-rupprechtii and P.crassifolia plantation forests significantly improved the soil capacity,soil total porosity,and capillary porosity,decreased soil bulk density,and enhanced water storage capacity,compared with the P.tabuliformis plantation forest.The results of this study showed that,the strong link between plants and soil was tightly coupled to C:N and C:P,and there was a close correlation between soil particle size distribution and soil physicochemical properties.Conclusions:Therefore,our results recommend planting the L.principis-rupprechtii and P.crassifolia as the preferred tree species to enhance the soil fertility and water conservation functions,especially in semi-arid regions mountain forest ecosystems.展开更多
Background: Land-use change and forest management may alter soil organic matter(SOM) and nutrient dynamics,due in part to alterations in litter input and quality. Acacia was introduced in eucalypt plantations establis...Background: Land-use change and forest management may alter soil organic matter(SOM) and nutrient dynamics,due in part to alterations in litter input and quality. Acacia was introduced in eucalypt plantations established in the Congolese coastal plains to improve soil fertility and tree growth. Eucalypt trees were expected to benefit from N2 fixed by acacia. However, some indicators suggest a perturbation in SOM and P dynamics might affect the sustainability of the system in the medium and long term. In tropical environments, most of the nutrient processes are determined by the high rates of organic matter(OM) mineralization. Therefore, SOM stability might play a crucial role in regulating soil-plant processes. In spite of this, the relationship between SOM quality, C and other nutrient dynamics are not well understood. In the present study, OM quality and P forms in forest floor and soil were investigated to get more insight on the C and P dynamics useful to sustainable management of forest plantations.Methods: Thermal analysis(differential scanning calorimetry(DSC) and thermogravimetry(TGA)) and nuclear magnetic resonance(solid state13 C CPMASS and NMR and31 P-NMR) spectroscopy have been applied to partially decomposed forest floor and soils of pure acacia and eucalypt, and mixed-species acacia-eucalypt stands.Results: Thermal analysis and13 C NMR analysis revealed a more advanced stage of humification in forest floor of acacia-eucalypt stands, suggesting a greater microbial activity in its litter. SOM were related to the OM recalcitrance of the forest floor, indicating this higher microbial activity of the forest floor in this stand might be favouring the incorporation of C into the mineral soil.Conclusions: In relation with the fast mineralization in this environment, highly soluble orthophosphate was the dominant P form in both forest floor and soils. However, the mixed-species forest stands immobilized greater P in organic forms, preventing the P losses by leaching and contributing to sustain the P demand in the medium term.This shows that interactions between plants, microorganisms and soil can sustain the demand of this ecosystem.For this, the forest floor plays a key role in tightening the P cycle, minimizing the P losses.展开更多
基金This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20100101)a Major Special Science and Technology Project of Gansu Province(18ZD2FA009)the National Natural Science Foundation of China(NSFC)(31522013).
文摘Background:Large-scale afforestation can significantly change the ground cover and soil physicochemical properties,especially the soil fertility maintenance and water conservation functions of artificial forests,which are very important in semi-arid mountain ecosystems.However,how different tree species affect soil nutrients and soil physicochemical properties after afforestation,and which is the best plantation species for improving soil fertility and water conservation functions remain largely unknown.Methods:This study investigated the soil nutrient contents of three different plantations(Larix principis-rupprechtii,Picea crassifolia,Pinus tabuliformis),soils and plant-soil feedbacks,as well as the interactions between soil physicochemical properties.Results:The results revealed that the leaves and litter layers strongly influenced soil nutrient availability through biogeochemical processes:P.tabuliformis had higher organic carbon,ratio of organic carbon to total nitrogen(C:N)and organic carbon to total phosphorus(C:P)in the leaves and litter layers than L.principis-rupprechtii or P.crassifolia,suggesting that higher C:N and C:P hindered litter decomposition.As a result,the L.principis-rupprechtii and P.crassifolia plantation forests significantly improved soil nutrients and clay components,compared with the P.tabuliformis plantation forest.Furthermore,the L.principis-rupprechtii and P.crassifolia plantation forests significantly improved the soil capacity,soil total porosity,and capillary porosity,decreased soil bulk density,and enhanced water storage capacity,compared with the P.tabuliformis plantation forest.The results of this study showed that,the strong link between plants and soil was tightly coupled to C:N and C:P,and there was a close correlation between soil particle size distribution and soil physicochemical properties.Conclusions:Therefore,our results recommend planting the L.principis-rupprechtii and P.crassifolia as the preferred tree species to enhance the soil fertility and water conservation functions,especially in semi-arid regions mountain forest ecosystems.
基金supported by a TWAS-ENEA Research Training Fellowship Programme in Italy。
文摘Background: Land-use change and forest management may alter soil organic matter(SOM) and nutrient dynamics,due in part to alterations in litter input and quality. Acacia was introduced in eucalypt plantations established in the Congolese coastal plains to improve soil fertility and tree growth. Eucalypt trees were expected to benefit from N2 fixed by acacia. However, some indicators suggest a perturbation in SOM and P dynamics might affect the sustainability of the system in the medium and long term. In tropical environments, most of the nutrient processes are determined by the high rates of organic matter(OM) mineralization. Therefore, SOM stability might play a crucial role in regulating soil-plant processes. In spite of this, the relationship between SOM quality, C and other nutrient dynamics are not well understood. In the present study, OM quality and P forms in forest floor and soil were investigated to get more insight on the C and P dynamics useful to sustainable management of forest plantations.Methods: Thermal analysis(differential scanning calorimetry(DSC) and thermogravimetry(TGA)) and nuclear magnetic resonance(solid state13 C CPMASS and NMR and31 P-NMR) spectroscopy have been applied to partially decomposed forest floor and soils of pure acacia and eucalypt, and mixed-species acacia-eucalypt stands.Results: Thermal analysis and13 C NMR analysis revealed a more advanced stage of humification in forest floor of acacia-eucalypt stands, suggesting a greater microbial activity in its litter. SOM were related to the OM recalcitrance of the forest floor, indicating this higher microbial activity of the forest floor in this stand might be favouring the incorporation of C into the mineral soil.Conclusions: In relation with the fast mineralization in this environment, highly soluble orthophosphate was the dominant P form in both forest floor and soils. However, the mixed-species forest stands immobilized greater P in organic forms, preventing the P losses by leaching and contributing to sustain the P demand in the medium term.This shows that interactions between plants, microorganisms and soil can sustain the demand of this ecosystem.For this, the forest floor plays a key role in tightening the P cycle, minimizing the P losses.
