Results 11 to 20 of about 27,519 (160)
Soil Type Database of China: A nationwide soil dataset based on the Second National Soil Survey
中国科学数据, 2022 Derived from the Second National Soil Survey, Soil Type Database of China is the most comprehensive soil data resource on the national scale.
Shi Jianping, Song Ge
doaj +1 more source
Optical spectrum of the post-AGB Star HD56126 in the wavelength interval 4010-8790 Å Å [PDF]
Astrophysical Bulletin, 2007 The optical spectrum of the post-AGB star HD56126 identified with the infrared source IRAS07134+1005 is studied in detail using high spectral resolution observations (R = 25000 and 60000) performed with the echelle spectrographs of the 6-m telescope. A total of about one and a half thousand absorptions of neutral atoms and ions, absorption bands of C2,
V. G. Klochkova +3 more
openaire +1 more source
Measurement of the A-Value of the Intersystem Transition in Al II at 2670 Å: Å Progress Report [PDF]
International Astronomical Union Colloquium, 1984 Ratios of intensities of spectral lines produced in the radiative decay of collisionally-excited levels of atomic ions are versatile indicators of electron density in astrophysical plasmas when one of the lines involves a metastable level (see the review by Feldman 1981 and references therein). Radiative transition probabilities (A-values) and electron
B. Carol Johnson, H.S. Kwong
openaire +1 more source
Plant functional trait dissimilarity drives plant mixture effects on fine root biomass and trait variations. [PDF]
New PhytolSummary Fine roots are critical for soil resource uptake, yet how declining plant diversity alters fine root biomass (RB) and traits remains unclear. We tested how plant functional trait dissimilarity in shade tolerance, drought tolerance, growth rate, and nitrogen‐fixation ability drives variation in root attributes.
Peng S, Zhang Y, Chen HYH.
europepmc +2 more sources
Shuitu Baochi Xuebao, 2022 中国南方丘陵区存在着自然过程和人类活动交互影响的、土地利用—土地覆盖叠加变化的多种土壤景观，其土壤质量对乡村农业产业发展具有重要影响。在南京市远郊的溧水区晶桥镇芝山村域小流域，选取流域内生态保护的林地、农业利用的园地、旱地和稻田4种土壤景观，于秋季分别采集表土样品，测定土壤基础理化性质、土壤团聚体粒径组成及土壤微生物磷脂肪酸和胞外酶活性分布，分析土壤肥力、土壤团聚化、土壤生物活性等关键性质在不同土壤景观中的变异情况，并采用土壤质量评价方法探明土壤景观与表土质量的变化关系。结果表明，与原生林地相比 ...
赵正 +13 more
doaj
Effects of Biochar Application on Nitrogen and Phosphorus Availability in Soils: aReview [PDF]
, 2016 利用生物炭在贫瘠的土壤上培育出肥沃的"黑土"正成为土壤学家研究的热点.氮、磷等大量养分是衡量土壤肥力高低的重要指标,生物炭对其有效性影响表现出极大的复杂性.不同研究得出的结论不尽相同,关键是缺乏对其机制的深入研究.由于氮和磷的不合理利用还可能造成非点源污染而带来环境风险,再加之生物炭施用的不可逆性,必须确保生物炭在任何情况下都不会对土壤和环境带来不利的影响.为此,本文综述了生物炭添加对氮肥和磷肥在土壤-植物系统迁移转化过程中的作用,重点讨论了不同生物炭处理方式对土壤磷素吸附解吸和形态转化的影响 ...
张友 +4 more
core +1 more source
Shuitu Baochi Xuebao, 2002 采用对比分析的方法，研究了从自然土壤到森林土壤和农业土壤，最终演变为城市土壤的过程中，土壤质量的变化及其成因以及有机改土培肥措施对城市土壤质量有效性的影响。结果表明；城市土壤演变过程中土壤物理性质和养分含量发生了明显的变化。原始未受人为影响的五花草甸自然土壤的容重最小，农业老耕地土壤其次，森林土壤再次，城市土壤最大。城市绿化用地20－40cm土壤容重比别比森林土壤和农业土壤提高17.7%－43.7%和35.4%-93.9％。总孔隙度降低1.9%-13.0%和34.1%-52.4 ...
陈立新
doaj +2 more sources
Shuitu Baochi Xuebao, 2022 为探究不同气候条件下土壤水力参数对土壤水长程相关性的影响, 利用HYDRUS-1D模型, 以湿润、半干旱和干旱气候区的气象数据为驱动, 结合生成的砂土和黏壤土土壤水力参数集, 模拟生成土壤水时间序列集; 而后, 利用去趋势波动分析法对生成的土壤水数据进行长程相关性分析。结果表明: (1)土壤水标度指数(h)介于0.570~1.915, 土壤水中存在显著的长程相关性。砂土中土壤水变化主要表现为持续性, 黏壤土中持续性和反持续性均较为显著。(2)土壤水长程相关性与土层深度、黏粒含量、干旱指数存在正相关关系。(
李玲, 武冬冬, 王铁军, 狄崇利
doaj
塔里木沙漠公路防护林土壤微生物生物量与土壤环境因子的关系 [PDF]
, 2009 为探讨极端干旱区风沙土土壤微生物与土壤环境因子的作用规律,采用相关分析法研究了塔里木沙漠公路防护林地土壤微生物生物量与理化因子和酶活性的关系.结果表明:土壤容重和粒径减小(R0.85)时,防护林地中土壤微生物数量和生物量有增大趋势,由容重与微生物量的相关性主导;土壤养分含量与土壤微生物数量和生物量呈正相关,主要由速效养分和放线菌、微生物生物量C、P的相关性所致;土壤酶活性与土壤微生物数量和生物量的相关性差异较大,R在0.51～0.91,主要取决于蔗糖酶、磷酸酶与放线菌、微生物量C的相关 ...
周宏伟 +7 more
core
Taxonomic and functional diversity of urban bees of the world
Conservation Biology, EarlyView.Abstract Bees play a pivotal role in terrestrial environments. Urbanization can affect these organisms and the ecosystem services they provide. However, knowledge of the global diversity of urban bees is limited. Thus, we summarized data on urban bee species identities and occurrences; compared distributions of all bees with those found in urban ...
João C. F. Cardoso +10 more
wiley +1 more source