Black soils, characterized by their thick, dark horizons enriched with organic matter, epitomize highly fertile soils. However, their fertility precipitates intense land use, engendering challenges such as soil erosio...Black soils, characterized by their thick, dark horizons enriched with organic matter, epitomize highly fertile soils. However, their fertility precipitates intense land use, engendering challenges such as soil erosion, nutrient depletion, pollution, compaction, salinization, and acidification. Notably, these soils are significant contributors to global greenhouse gas emissions, primarily due to substantial losses in soil organic carbon. Despite these challenges, black soils are pivotal for global food production. This paper delineates the implementation of digital soil mapping for the global cartography of black soils and human interference on these soils. Predominantly distributed in Eastern Europe, Central and Eastern Asia, and North and South America, black soils cover an approximate area of 725 Mha, with the Russian Federation,Kazakhstan, and China collectively have over half of this area. Agriculturally,these soils underpin significant proportions of global crop yields, producing 66% of sunflower, 30% of wheat, and 26% of potato outputs. The organic carbon content in the upper 30 cm of these soils is estimated at 56 Gt.Sustainable management of black soils is imperative for ensuring food security and addressing climate change on a global scale.展开更多
The effect of a high magnetic field on the microstructural evolution of a peritectic Al—18 at.%Ni alloy during directional solidification and its dependence on pulling speed were investigated.At a low pulling speed,t...The effect of a high magnetic field on the microstructural evolution of a peritectic Al—18 at.%Ni alloy during directional solidification and its dependence on pulling speed were investigated.At a low pulling speed,the application of a 2 T magnetic field triggered the appearance of a primary Al_(3)Ni_(2)phase.At higher pulling speeds,a high magnetic field application induced primary Al_(3)Ni_(2)phase segregation that formed close to the central alloy regions.For all pulling speeds,the application of a high magnetic field induced bulk Al_(3)Ni/Al eutectic formation on the upper and lower parts of the alloys,and promoted elongated growth of the peritectic Al_3Ni phase along the magnetic field direction.Microstructural analysis indicated that microstructural evolution that was induced by high magnetic fields can be attributed to solute migration and melt flow that is regulated by magnetic,Lorentz,and thermoelectric magnetic forces and their coupling effects during peritectic solidification.展开更多
文摘Black soils, characterized by their thick, dark horizons enriched with organic matter, epitomize highly fertile soils. However, their fertility precipitates intense land use, engendering challenges such as soil erosion, nutrient depletion, pollution, compaction, salinization, and acidification. Notably, these soils are significant contributors to global greenhouse gas emissions, primarily due to substantial losses in soil organic carbon. Despite these challenges, black soils are pivotal for global food production. This paper delineates the implementation of digital soil mapping for the global cartography of black soils and human interference on these soils. Predominantly distributed in Eastern Europe, Central and Eastern Asia, and North and South America, black soils cover an approximate area of 725 Mha, with the Russian Federation,Kazakhstan, and China collectively have over half of this area. Agriculturally,these soils underpin significant proportions of global crop yields, producing 66% of sunflower, 30% of wheat, and 26% of potato outputs. The organic carbon content in the upper 30 cm of these soils is estimated at 56 Gt.Sustainable management of black soils is imperative for ensuring food security and addressing climate change on a global scale.
基金the National Natural Science Foundation of China(Nos.51690161,51774086,and 21701022)the Fundamental Research Funds for the Central Universities(Nos.N180915002,N170902002 and N170908001)Liaoning Innovative Research Team in University,China(No.LT2017011)。
文摘The effect of a high magnetic field on the microstructural evolution of a peritectic Al—18 at.%Ni alloy during directional solidification and its dependence on pulling speed were investigated.At a low pulling speed,the application of a 2 T magnetic field triggered the appearance of a primary Al_(3)Ni_(2)phase.At higher pulling speeds,a high magnetic field application induced primary Al_(3)Ni_(2)phase segregation that formed close to the central alloy regions.For all pulling speeds,the application of a high magnetic field induced bulk Al_(3)Ni/Al eutectic formation on the upper and lower parts of the alloys,and promoted elongated growth of the peritectic Al_3Ni phase along the magnetic field direction.Microstructural analysis indicated that microstructural evolution that was induced by high magnetic fields can be attributed to solute migration and melt flow that is regulated by magnetic,Lorentz,and thermoelectric magnetic forces and their coupling effects during peritectic solidification.
