基于检索1950-2016年发表在中国知网、Google Scholar、Web of Science等数据库的文章,筛选出关于我国退耕还草工程与土壤有机碳的文献123篇(126个研究地点)。基于筛选文献,提取了农田和恢复草地的土壤有机碳含量、土壤有效养分含量、...基于检索1950-2016年发表在中国知网、Google Scholar、Web of Science等数据库的文章,筛选出关于我国退耕还草工程与土壤有机碳的文献123篇(126个研究地点)。基于筛选文献,提取了农田和恢复草地的土壤有机碳含量、土壤有效养分含量、恢复时间和气候等数据735条,旨在探究我国退耕还草工程对土壤有机碳含量的影响及其主导因素。结果表明:1)农田恢复为草地后,土壤有机碳含量呈先下降后上升趋势(时间拐点约为第6年),整体上退耕还草工程使土壤有机碳含量提高了19.8%。2)土壤有机碳的正响应随土壤深度增加而减弱,且深度超过1 m时其正响应不明显。3)土壤有效氮是影响土壤有机碳恢复的主要因素,而土壤有效磷和植物功能群对其影响不大。4)沿着增加的水分梯度,土壤有机碳的恢复效果由负变正,转变阈值为25.15 (干旱指数)。总体而言,我国退耕还草工程对土壤有机碳含量的影响为正效应,此效应受环境梯度和恢复时间的共同影响。本研究能够为我国土地利用变化背景下土壤碳库管理的相关决策提供科学依据。展开更多
Soil salt transformation plays an important role in the freeze-thawing process,which is also one of basic problems of cryopedology. The very special law is made up of the two time salt-moisture transfer under freeze-t...Soil salt transformation plays an important role in the freeze-thawing process,which is also one of basic problems of cryopedology. The very special law is made up of the two time salt-moisture transfer under freeze-thawing condition. Based on the latest research at home and abroad,through the investigation of soil moisture-salt change in the freeze-thawing process,the conclusion is made that the soil water potential gradient is the main driving force of soil salt movement and the factors are of quantities. The research shows that,when freezing,temperature drops,salt and moisture move towards frozen layer. All make the salinity content of the frozen layer increase significantly. In the thawing process,salinity and moisture in the soil move up again with evaporation and makes the salt second migration.展开更多
Time-domain reflectometry was used to make continuous measurements of soil moisture to 18 sample points with depth of 2 m for 36 months in a typical artificial secondary oak forest located in a hilly area on Zijin Mou...Time-domain reflectometry was used to make continuous measurements of soil moisture to 18 sample points with depth of 2 m for 36 months in a typical artificial secondary oak forest located in a hilly area on Zijin Mountain in the suburbs of Nanjing,China.The data were then used to examine the patterns of soil moisture variations on temporal and spatial scales and predict the relationships between soil moisture and major factors of both meteorology and topography.Water in the topsoil was active,and the upper 30 cm of soil supplied about 43% of the water content variation during the whole year.This difference of water content changes among layers could be due to the distribution conditions of some soil physical properties.When initial soil moisture was in the range from 10% to 40%,the impact of a single storm event on soil moisture was extremely significant,especially on sunny slope.Both climate and slope condition were related to soil moisture change,and the impact of slope gradient on soil moisture was higher that on shady slope.Moreover,root uptake was another important path of soil water consumption.展开更多
为了探究施用生物炭后土壤性质和重金属形态随时间变化过程,通过5种矿区土壤的玉米(Zea mays L.)盆栽实验,研究施用生物炭后土壤和孔隙水性质、梯度扩散薄膜(diffusive gradients in thin films,DGT)技术测定的Zn浓度(CDGT-Zn)和欧共体...为了探究施用生物炭后土壤性质和重金属形态随时间变化过程,通过5种矿区土壤的玉米(Zea mays L.)盆栽实验,研究施用生物炭后土壤和孔隙水性质、梯度扩散薄膜(diffusive gradients in thin films,DGT)技术测定的Zn浓度(CDGT-Zn)和欧共体标准物质局共识(Bureau of Community right-to-know,BCR)有效态Zn含量(弱酸提取态Zn^(+)可还原态Zn,C_(BCR-Zn))随时间变化的过程。施用生物炭后,随土壤培养时间的增加,土壤阳离子交换量(cation exchange capacity,CEC)增加了20.35%~65.65%,孔隙水pH上升0.34~1.02个单位,溶解性有机碳(dissolved organic carbon,DOC)浓度CDOC先升后降,最终下降了8.21%~33.23%,孔隙水Zn浓度(C_(pw-Zn))下降了17.46%~49.67%,C_(DGT-Zn)、C_(BCR-Zn)分别下降了18.64%~50.00%、23.33%~64.71%。随玉米栽培时间的增加,土壤CEC增加了7.94%~28.97%,C_(DOC)、C_(pw-Zn)、C_(DGT-Zn)、C_(BCR-Zn)分别下降了10.43%~41.26%、9.62%~34.21%、10.42%~30.70%、14.68%~61.62%,孔隙水pH无明显变化。生物炭能明显改变土壤和孔隙水性质,降低Zn的生物有效性,从而降低土壤中过量Zn对玉米的危害。展开更多
植物多样性格局作为生物多样性维持的一个重要方面可揭示群落构建的信息,反映物种对环境的适应性。结合样带调查和实验分析的方法,研究新疆艾比湖湿地自然保护区内水盐梯度下荒漠植物多样性格局及其与土壤环境因子间关系。结果表明:(1)...植物多样性格局作为生物多样性维持的一个重要方面可揭示群落构建的信息,反映物种对环境的适应性。结合样带调查和实验分析的方法,研究新疆艾比湖湿地自然保护区内水盐梯度下荒漠植物多样性格局及其与土壤环境因子间关系。结果表明:(1)高、低水盐样地(SW1,SW2)土壤容积含水量(SVWC)和电导率(EC)分别为16.65%和12.02 m S/cm及2.63%和1.91m S/cm,水盐变化主要影响草本和部分灌木群落的植物组成;(2)高水盐生境下植物群落无明显趋势性分布,低水盐生境下植物种依水盐和营养元素呈区域性分布。(3)高水盐生境下荒漠植物的多度分布呈对数正态模型,低水盐条件下符合Zipf模型,多度分布的变化反映了群落组成结构的水盐梯度响应;(4)SW1样地多样性总体显著高于SW2样地,土壤p H、SVWC和硫(S)对植物多样性有不同程度的极显著影响。综上可知,荒漠植物分布及多样性格局与土壤环境间关系呈一定的水盐梯度响应规律,本研究可为该地区植被恢复和土壤盐渍化治理提供科学依据。展开更多
文摘Soil salt transformation plays an important role in the freeze-thawing process,which is also one of basic problems of cryopedology. The very special law is made up of the two time salt-moisture transfer under freeze-thawing condition. Based on the latest research at home and abroad,through the investigation of soil moisture-salt change in the freeze-thawing process,the conclusion is made that the soil water potential gradient is the main driving force of soil salt movement and the factors are of quantities. The research shows that,when freezing,temperature drops,salt and moisture move towards frozen layer. All make the salinity content of the frozen layer increase significantly. In the thawing process,salinity and moisture in the soil move up again with evaporation and makes the salt second migration.
基金Project(TD2011-01)supported by the Fundamental Research Funds for the Central Universities,China
文摘Time-domain reflectometry was used to make continuous measurements of soil moisture to 18 sample points with depth of 2 m for 36 months in a typical artificial secondary oak forest located in a hilly area on Zijin Mountain in the suburbs of Nanjing,China.The data were then used to examine the patterns of soil moisture variations on temporal and spatial scales and predict the relationships between soil moisture and major factors of both meteorology and topography.Water in the topsoil was active,and the upper 30 cm of soil supplied about 43% of the water content variation during the whole year.This difference of water content changes among layers could be due to the distribution conditions of some soil physical properties.When initial soil moisture was in the range from 10% to 40%,the impact of a single storm event on soil moisture was extremely significant,especially on sunny slope.Both climate and slope condition were related to soil moisture change,and the impact of slope gradient on soil moisture was higher that on shady slope.Moreover,root uptake was another important path of soil water consumption.
文摘为了探究施用生物炭后土壤性质和重金属形态随时间变化过程,通过5种矿区土壤的玉米(Zea mays L.)盆栽实验,研究施用生物炭后土壤和孔隙水性质、梯度扩散薄膜(diffusive gradients in thin films,DGT)技术测定的Zn浓度(CDGT-Zn)和欧共体标准物质局共识(Bureau of Community right-to-know,BCR)有效态Zn含量(弱酸提取态Zn^(+)可还原态Zn,C_(BCR-Zn))随时间变化的过程。施用生物炭后,随土壤培养时间的增加,土壤阳离子交换量(cation exchange capacity,CEC)增加了20.35%~65.65%,孔隙水pH上升0.34~1.02个单位,溶解性有机碳(dissolved organic carbon,DOC)浓度CDOC先升后降,最终下降了8.21%~33.23%,孔隙水Zn浓度(C_(pw-Zn))下降了17.46%~49.67%,C_(DGT-Zn)、C_(BCR-Zn)分别下降了18.64%~50.00%、23.33%~64.71%。随玉米栽培时间的增加,土壤CEC增加了7.94%~28.97%,C_(DOC)、C_(pw-Zn)、C_(DGT-Zn)、C_(BCR-Zn)分别下降了10.43%~41.26%、9.62%~34.21%、10.42%~30.70%、14.68%~61.62%,孔隙水pH无明显变化。生物炭能明显改变土壤和孔隙水性质,降低Zn的生物有效性,从而降低土壤中过量Zn对玉米的危害。
文摘植物多样性格局作为生物多样性维持的一个重要方面可揭示群落构建的信息,反映物种对环境的适应性。结合样带调查和实验分析的方法,研究新疆艾比湖湿地自然保护区内水盐梯度下荒漠植物多样性格局及其与土壤环境因子间关系。结果表明:(1)高、低水盐样地(SW1,SW2)土壤容积含水量(SVWC)和电导率(EC)分别为16.65%和12.02 m S/cm及2.63%和1.91m S/cm,水盐变化主要影响草本和部分灌木群落的植物组成;(2)高水盐生境下植物群落无明显趋势性分布,低水盐生境下植物种依水盐和营养元素呈区域性分布。(3)高水盐生境下荒漠植物的多度分布呈对数正态模型,低水盐条件下符合Zipf模型,多度分布的变化反映了群落组成结构的水盐梯度响应;(4)SW1样地多样性总体显著高于SW2样地,土壤p H、SVWC和硫(S)对植物多样性有不同程度的极显著影响。综上可知,荒漠植物分布及多样性格局与土壤环境间关系呈一定的水盐梯度响应规律,本研究可为该地区植被恢复和土壤盐渍化治理提供科学依据。