Few studies have compared the variability of soil properties using different types of mulches in semi-arid forests.This study evaluated the changes in physico-chemical soil properties in a semi-arid forest of Central ...Few studies have compared the variability of soil properties using different types of mulches in semi-arid forests.This study evaluated the changes in physico-chemical soil properties in a semi-arid forest of Central Eastern Spain,where straw and pine wood chips were distributed as mulch three months after a wildfire.Soils were sampled under burned and unmulched and burned and mulched plots three and nine months after the treatments.The data was processed using Principal Component Analysis(PCA)and Analytical Hierarchical Cluster Analysis(AHCA).Mulching with straw or wood chips did not have any significant effects on the texture and chemical properties of burned sites few months after the treatment.In contrast,significant changes are expected over time in organic matter,nutrients and many ions.There were no significant differences in soil properties between the two mulches.These low changes were confirmed by PCA coupled with AHCA,which did not show a clear distinction among the three soil conditions.However,a noticeable and significant variability of many of these properties over time was evident.This study shows that mulching does not degrade of soil properties in the short-term after a wildfire and after post-fire treatments,and thus helps protect semi-arid forest ecosystems against the negative impacts of high-severity fires.展开更多
Quantitative weathering indices are efficient tools in determining the soil development from the underlying rocks.In order to evaluate the effects of climate on the soils developed under an arid to sub-humid climosequ...Quantitative weathering indices are efficient tools in determining the soil development from the underlying rocks.In order to evaluate the effects of climate on the soils developed under an arid to sub-humid climosequence in central Iran,twenty soil-development indices were compared.Twentyfour samples from six pedons were analyzed for routine physico-chemical and geochemical analyses using X-ray fluorescence(XRF).The lowest and highest calculated soil development indices were observed in the arid and sub-humid regions respectively.Among the studied indices,fifteen indices showed similar trends concerning the intensity of weathering.The consistency of such trends reveals the feasibility of using these indices to evaluate basalt weathering rate and soil development in arid,semi-arid and sub-humid regions.This study demonstrated that,among the evaluated weathering indices,the Weathering Index of Parker(WIP)and mass transfer coefficient(τ)were the most proper indices for predicting basalt weathering intensity.This is due to the fact that these indices use the highly mobile earth elements which are the most sensitive elements in basalt chemical weathering.The calculated indices were subdivided into three subgroups including the ratios of mobile/immobile,mobile/mobile and immobile/mobile elements based on the elements used in their calculation.The state of soil evolution was more accurately predicted compared to the other subgroups using the mobile/immobile subgroup of indices.Overall,the weathering indices calculated using the mobile elements are better indicators of weathering intensity,soil formation and the exogenous processes across the arid to sub-humid climosequence.展开更多
This study was conducted to analyze the variation of soil multifunctionality(SMF)along elevation and the driving factors in the Altun Shan.Soil samples(0–10 cm)were collected from 15 sites(H01 to H15)at every 200 m e...This study was conducted to analyze the variation of soil multifunctionality(SMF)along elevation and the driving factors in the Altun Shan.Soil samples(0–10 cm)were collected from 15 sites(H01 to H15)at every 200 m elevation interval,covering a total range from 900 m to 3500 m above mean sea level.We investigated climate factors(mean annual temperature,MAT;mean annual precipitation,MAP),soil environment(soil water content,electrical conductance,and pH),vegetation factors,and elevation to determine which of them are the main driving factors of the spatial variability of SMF in the Altun Shan.We explored the best-fit model of SMF along the changes in elevation using a structural equation model,performed variance partitioning analysis(VPA)on SMF with the“varpart”function to explain the relative contribution of various environmental factors to SMF changes,and used a random forest model for relative importance analysis.The results showed that SMF in the Altun Shan significantly increased with elevation in a linear trend.The main driver of changes in SMF was found to be MAP.Although the rise in elevation did not have a significant direct effect on changes in SMF,it could indirectly affect SMF by significantly influencing MAP,p H,MAT,and normalized difference vegetation index(NDVI).When considering climate,soil environment,and vegetation factors together,they explained 76%of the variation in SMF.The largest contribution to the variation in SMF was attributed to the independent effect of climate(0.31)and its interactive effect with soil(0.30).The relative importance of MAP on SMF changes was found to be the greatest.It is indicated that changes in SMF are caused by the combined effect of multiple environmental conditions.These findings are essential for understanding the spatial variability and drivers of SMF in dryland mountain ecosystems,especially concerning the function of mountain ecosystems in the context of global climatic changes.展开更多
Soils developed in the alluvium terraces of the River Nile at Khartoum North, Sudan was analyzed in an attempt to classify it as well as to refer them to their origin. Three river terraces comprising nine profiles wer...Soils developed in the alluvium terraces of the River Nile at Khartoum North, Sudan was analyzed in an attempt to classify it as well as to refer them to their origin. Three river terraces comprising nine profiles were selected to cover the physiographic positions. Lack of B horizon and carbonate accumulation were main pedogenic processes in subsurface horizons, whereas orhric epipedon was developed on top soil surface. The microscopic inspection of heavy sand mineralogy indicated that the origin of the sand was the Ethiopian plateau. The most abundant clay mineral was smectite, followed by illite, kaolinite and chlorite. The presences of micas (illite) and chlorite in all studied soil samples might emphasize that these soils were young from the pedological viewpoint and less weathered. The soils of the River Nile terraces at Khartoum North were classified into: Typic Torrifluvents (1st terrace), Entic Haplocambids (2nd terrace) and Typic Haplocambids (3rd terrace). Mineralogy analysis indicated that the Entisols and Aridisols of the River Nile terraces in the study area had the same origin that of the igneous and metamorphic rocks from Ethiopian plateau.展开更多
基金funded by the Spanish Research Agency(AEI)(project code PID2021-126946OB-I00)the financial support from the EPy RIS(SOE2/P5/E0811)project funded by the European Union through the SUDOE INTERREG Program。
文摘Few studies have compared the variability of soil properties using different types of mulches in semi-arid forests.This study evaluated the changes in physico-chemical soil properties in a semi-arid forest of Central Eastern Spain,where straw and pine wood chips were distributed as mulch three months after a wildfire.Soils were sampled under burned and unmulched and burned and mulched plots three and nine months after the treatments.The data was processed using Principal Component Analysis(PCA)and Analytical Hierarchical Cluster Analysis(AHCA).Mulching with straw or wood chips did not have any significant effects on the texture and chemical properties of burned sites few months after the treatment.In contrast,significant changes are expected over time in organic matter,nutrients and many ions.There were no significant differences in soil properties between the two mulches.These low changes were confirmed by PCA coupled with AHCA,which did not show a clear distinction among the three soil conditions.However,a noticeable and significant variability of many of these properties over time was evident.This study shows that mulching does not degrade of soil properties in the short-term after a wildfire and after post-fire treatments,and thus helps protect semi-arid forest ecosystems against the negative impacts of high-severity fires.
基金Agriculture and Natural Resources,University of Tehran for financial support of the study(Grant No.7104017/6/18)。
文摘Quantitative weathering indices are efficient tools in determining the soil development from the underlying rocks.In order to evaluate the effects of climate on the soils developed under an arid to sub-humid climosequence in central Iran,twenty soil-development indices were compared.Twentyfour samples from six pedons were analyzed for routine physico-chemical and geochemical analyses using X-ray fluorescence(XRF).The lowest and highest calculated soil development indices were observed in the arid and sub-humid regions respectively.Among the studied indices,fifteen indices showed similar trends concerning the intensity of weathering.The consistency of such trends reveals the feasibility of using these indices to evaluate basalt weathering rate and soil development in arid,semi-arid and sub-humid regions.This study demonstrated that,among the evaluated weathering indices,the Weathering Index of Parker(WIP)and mass transfer coefficient(τ)were the most proper indices for predicting basalt weathering intensity.This is due to the fact that these indices use the highly mobile earth elements which are the most sensitive elements in basalt chemical weathering.The calculated indices were subdivided into three subgroups including the ratios of mobile/immobile,mobile/mobile and immobile/mobile elements based on the elements used in their calculation.The state of soil evolution was more accurately predicted compared to the other subgroups using the mobile/immobile subgroup of indices.Overall,the weathering indices calculated using the mobile elements are better indicators of weathering intensity,soil formation and the exogenous processes across the arid to sub-humid climosequence.
基金the Tianshan Talent Plan(2022TSYCCX0001)Natural Science Foundation of Xinjiang(2022D01D083)+1 种基金the National Natural Science Foundation of China(U2003214 and 41977099)the Ecological Processes and Biological Adaptation team for financial and experimental instrumentation help。
文摘This study was conducted to analyze the variation of soil multifunctionality(SMF)along elevation and the driving factors in the Altun Shan.Soil samples(0–10 cm)were collected from 15 sites(H01 to H15)at every 200 m elevation interval,covering a total range from 900 m to 3500 m above mean sea level.We investigated climate factors(mean annual temperature,MAT;mean annual precipitation,MAP),soil environment(soil water content,electrical conductance,and pH),vegetation factors,and elevation to determine which of them are the main driving factors of the spatial variability of SMF in the Altun Shan.We explored the best-fit model of SMF along the changes in elevation using a structural equation model,performed variance partitioning analysis(VPA)on SMF with the“varpart”function to explain the relative contribution of various environmental factors to SMF changes,and used a random forest model for relative importance analysis.The results showed that SMF in the Altun Shan significantly increased with elevation in a linear trend.The main driver of changes in SMF was found to be MAP.Although the rise in elevation did not have a significant direct effect on changes in SMF,it could indirectly affect SMF by significantly influencing MAP,p H,MAT,and normalized difference vegetation index(NDVI).When considering climate,soil environment,and vegetation factors together,they explained 76%of the variation in SMF.The largest contribution to the variation in SMF was attributed to the independent effect of climate(0.31)and its interactive effect with soil(0.30).The relative importance of MAP on SMF changes was found to be the greatest.It is indicated that changes in SMF are caused by the combined effect of multiple environmental conditions.These findings are essential for understanding the spatial variability and drivers of SMF in dryland mountain ecosystems,especially concerning the function of mountain ecosystems in the context of global climatic changes.
文摘Soils developed in the alluvium terraces of the River Nile at Khartoum North, Sudan was analyzed in an attempt to classify it as well as to refer them to their origin. Three river terraces comprising nine profiles were selected to cover the physiographic positions. Lack of B horizon and carbonate accumulation were main pedogenic processes in subsurface horizons, whereas orhric epipedon was developed on top soil surface. The microscopic inspection of heavy sand mineralogy indicated that the origin of the sand was the Ethiopian plateau. The most abundant clay mineral was smectite, followed by illite, kaolinite and chlorite. The presences of micas (illite) and chlorite in all studied soil samples might emphasize that these soils were young from the pedological viewpoint and less weathered. The soils of the River Nile terraces at Khartoum North were classified into: Typic Torrifluvents (1st terrace), Entic Haplocambids (2nd terrace) and Typic Haplocambids (3rd terrace). Mineralogy analysis indicated that the Entisols and Aridisols of the River Nile terraces in the study area had the same origin that of the igneous and metamorphic rocks from Ethiopian plateau.
