Changes in soil properties across a chronosequence of vegetation restoration on the Loess Plateau of China

Soil fertility is important for vegetation growth and productivity. The relationship between vegetation and soil fertility is important for both scientific and practical reasons. However, the effects of soil fertility on vegetation development and succession are poorly documented on the Loess Plateau. In this study, we compared soil properties of the Yanhe Watershed in northern Shaanxi across five different land uses (shrubland, farmland, natural grassland, woodland and artificial grassland) and a chronosequence of soils undergoing restoration for 5, 10, 15, 20, 25, 30, 35, 40 and 45 years. We found that revegetation had a positive effect on soil bulk density decrease, total porosity and capillary porosity increase in the surface soil layers but not in the subsurface layer. Additionally, soil organic matter, total nitrogen, available nitrogen and available potassium were greater at shrubland and woodland sites compared with other land uses. Total phosphorus and available phosphorus were greater at farmland sites. Results of the study indicate that revegetation on eroded soil can produce important increases in soil fertility on older plantations and in areas with natural succession.     

植被性状与高原鼢鼠栖息地适合度的关系

本研究以鼠群密度代表生境适合度,在高原鼢鼠(Myospalax baileys)5个密度梯度上对植被盖度、高度、地上生物量和植物多样性等性状指标进行了分析.结果表明,植被性状的各项指标均与鼠群密度存在显著的相关性.其中,植被盖度和高度与高原鼢鼠种群密度表现为极显著线性相关,地上生物量和植物多样性表现为非线性(单峰曲线)...     

青藏高原藏羊狂蝇蛆的形态学观察

应用低倍显微镜和实体显微镜对采自青藏高原等地区的羊狂蝇一期幼虫、二期幼虫、三期幼虫的形态特征进行了详尽的观察并对不同海拔高度地区的样本的细微形态结构进行了比较,发现它们之间仅有较小的个体差异,其基本特征性形态显示一致,从而确认青海省的6个县市、甘肃省的3个县市的狂蝇蛆同属一种。     

黑头噪鸦的活动区、种群密度和栖息地利用

黑头噪鸦(Perisoreus internigrans)是我国青藏高原高山针叶林的特有鸟类,种群数量稀少,一些基本生活史资料至今依然缺乏.我们于2001-2004年间对该物种在卓尼和九寨沟地区的种群状况和栖息地选择进行了研究.研究表明黑头噪鸦通常以平均3.8只个体构成的“群体”形式活动,平均家域大小为42.0 ha,...     

黄土丘陵区黑穗醋栗引种试验报告

对从国内牙引进的１５个黑穗醋栗品种，进行生物学特性和生态适应性，经济效益等观察与分析，初步得出品种中牡丹８０－１－１和薄皮表现最好。其单株产量分别为０．３６ｋｇ和０．３０ｋｇ，每公顷产量为６３００ｋｇ，果实出汁率为７５％。根系呈网状结构，保水固土能力强。     

蒙古高原鸦葱属植物分类和地理分布研究

确认了蒙古高原有鸦葱属植物10种；把ScorzoneraikonnikoviiLipsch.etKrasch.和S.manshuricaNakai并入了S.austriacaWilld.；把S.sinensisLipsch.etKrasch.划为S.austriacaWilld的一个变种；对《内蒙古植物志》（第2版，第4册）所描述的一些种的不确切分布进行了更正、补充；《内蒙古植物志》（第2版，第4册）记载的S.muriculataChang应为河西菊属HexiniaH.L.Yang的河西菊H.polydicotoma(Ostenf.)H.L.Yang，该种在内蒙古没有分布；确定了蒙古高原鸦葱属植物的区系地理成分；编制了蒙古高原鸦葱属植物分种检索表。     

牧场草在黄土高原地区的引种栽培试验

美国Regar牧场草在黄土高原地区引种后的适应性很强 ,除风沙区为一般适生区外 ,其他各类型区均为适生中心区。其生长迅速 ,产草量较高 ,草质适口性好 ,生态经济利用价值很高 ,栽培技术简便易行 ,是黄土高原十分理想的一种兼用型引进牧草 ,在饲料、水土保持等方面具有广阔的推广前景     

绿色饲用植物--细绿萍在黄土高原引种栽培

原产于美国的细绿萍70年代在西方国家广泛应用，中国科学院引进我国后，经过多年的驯化已经适宜我国北方地区养殖，作为优质的家畜饲料引进陇东黄土高原栽培，推广，具有产量高、宜推广、经济效益、社会效益、生态效益显著的特点。     

Geographic variations in particle size distribution of the last interglacial pedocomplex S1 across the Chinese Loess Plateau: Their chronological and pedogenic implications

Due to northwestward attenuation of the summer monsoon and northwestward intensification of loess deposition during the last interglacial, the last interglacial pedocomplex S1 gradually differentiated from the northwest to the southeast. The three paleosols (S1S1, S1S2, S1S3) corresponding to the marine isotope sub-stages 5a, 5c, and 5e and the two intercalated loess units (S1L1, S1L2) corresponding to the marine isotope sub-stages 5b and 5d are completely preserved at northwestern sections. Towards southeast, both the S1L1 and S1L2 were annexed by the subsequent paleosol development (S1S1 and S1S2) and the three paleosols (S1S1, S1S2, and S1S3) were partially welded. At the southeasternmost site, the three soil-forming events (S1S1, S1S2, and S1S3) repeatedly occurred in a single paleosol profile. The three observed orders of particle-size variations are interpreted to have imprinted important chronological and pedogenic signatures. First-order variations, i.e., a remarkable difference between the interglacial pedocomplex S1 and the glacial loess units (L1 and L2), implies that the S1 parent material was considerably finer in the source areas or/and the proximity to the source areas was much farther during interglacial period than during the preceding (L2) and following (L1) glacial periods. Second-order variation, i.e., the parenthetical trends in > 63 μm and < 10 μm fraction curves, might have resulted from the delayed response of the source material supplies to the climate changes. The third-order variations in < 10 μm fraction correspond well to the variations in frequency-dependent magnetic susceptibility, suggesting that pedogenically formed finer particles (i.e., < 10 μm fraction) and the associated ultra-fine paramagnetic minerals as expressed by the frequency-dependent susceptibility occurred only as a minor component of the < 10 μm fraction. The third-order variations seem to be obscured by soil welding and annexation at southeastern sections where the paleosols within the S1 were partially or completely welded. The laboratory data-indicated < 10 μm fraction peaks of the third-order and field-observed clay coatings on ped-faces, together with carbonate leaching and accumulation, in the paleosols within the S1 indicate occurrence of within-S1 material translocation. To sum up, it is unrealistic to reconstruct high-resolution climatic records from the S1 pedocomplex because a number of factors might have undermined the validity of the particle size as a winter monsoon proxy. These factors include weathering in the source areas, in situ post-depositional weathering and fine fraction translocation, and downward penetration of soil formation into underlying previously deposited materials on stable land surfaces.