中国四省未开垦表土硫源识别研究     

XIAO Hua-Yun  LI Nan  LIU Cong-Qiang 《土壤圈》2015,25(1):140-149

The analysis of stable isotopes of sulfur(δ34S) is a useful tool for identifying sources of sulfur in soils. Concentrations and sulfur(S)isotopes of water-soluble sulfate(WSS), adsorbed sulfate(AS), residual sulfur(RS), and total sulfur(TS) in uncultivated surface soils of four Chinese provinces were systematically analyzed for identifying sources of S in the soils. Green and healthy mosses(Haplocladium microphyllum) were sampled as bioindicators. The mean WSS concentration(27.8 ± 23.4 mg kg-1) in the surface soils was lower than those of AS(101.4 ± 57.0 mg kg-1) and RS(381.5 ± 256.7 mg kg-1). The mean δ34S values of WSS and AS were very similar(about2.0‰), lower than those of RS(8.0‰) and TS(6.1‰). A significant linear correlation was found between the δ34S values of AS and WWS(y = 1.0002x- 0.0557, P 0.0001), indicating that sulfate adsorption in the soils did not markedly fractionate S. All S species in the soils of Guizhou Province were characterized by the lowest δ34S values, consistent with the most34S-depleted rainwater sulfate reported at Guiyang of Guizhou Province. The δ34S values of sulfate in mosses and rainwater previously reported were significantly linearly correlated with those of both WWS and AS in surface soils, suggesting that atmospheric S input was an important source for soil WSS and AS. However, there were no significant correlations between isotopic composition of rainwater sulfate and RS or TS.The slopes of all these significant linear correlations(soil/rainwater or soil/moss isotopic ratio) were 0.4–0.6, indicating that inorganic sulfate in the surface soils should be a result of mixing of deposited atmospheric sulfate with a more34S-depleted sulfate component possibly from mineralization of RS.  相似文献   

旱生藓类植物——厚肋流苏藓（Crossidium crassinerve）在陕西省的新记录及其生态作用     

刘永英  卜崇峰  孟杰  李敏  赵建成 《干旱区研究》2011,28(5):820-825

首次记录了厚肋流苏藓〔Crossidium crassinerve（De Not.）Jur.〕及流苏藓属（Crossidium）在陕西省的分布,详尽描述了该种的形态结构,对叶片绿色丝体细胞、蒴齿、基膜、孢子、生殖苞、假根等重要结构进行了扫描电镜观察。从茎、叶结构、绿色丝体、群落、繁殖方式等方面分析了适应干旱环境的特征,...  相似文献   

干旱人工植被区藻结皮光合固碳的时间效应研究     

苏延桂  李新荣  张志山  陈应武  鲁艳 《土壤学报》2011,48(3):570-577

研究了腾格里沙漠东南缘沙坡头地区不同建植年限(16、21、27、44和52a)人工植被区中发育藻结皮的净光合速率、年固碳量和累计固碳量变化特征,并分析了其与结皮生物学参数(盖度和生物量)和土壤表层0~3 cm有机碳含量的相关关系。结果表明:1)随着人工植被区建植年限的增加,藻结皮的最大净光合速率显著增加,从植被建植16a藻结皮的1.63μmol m-2s-1增加至植被建植52a的2.81μmol m-2s-1;藻结皮的最大光合速率与结皮生物量和结皮盖度呈显著正相关关系;2)藻结皮的年固碳量随植被区建植年限的延长呈指数增加,随着人工植被区建植年限的增加,藻结皮的年固碳量显著增加,从建植16a藻结皮的C 0.2 g m-2a-1增加到52a的C 2.78 g m-2a-1;3)植被区建植后,藻结皮的固碳总量经历两个阶段的变化,建植16a到27a,藻结皮固碳总量在C 2.2~6.2 g m-2,建植44a后,固碳总量增加到C 23.9 g m-2;并且,藻结皮的固碳总量与土壤表层有机碳含量呈显著线性正相关关系。以上研究结果说明,随着人工植被固沙区的演替,藻结皮发育成熟度逐渐提高,其光合固碳能力显著提高,有利于干旱区土壤有机碳的累计。  相似文献   

森林枯落物及其苔藓层阻延径流速度研究   总被引：17，自引：2，他引：17  

陈奇伯  张洪江 《北京林业大学学报》1996,18(1):1-5

运用室内水槽实验方法，研究了马尾松林枯落物层和枯落物与苔藓组合层对径流速度的影响．结果表明，径流速度与坡度和流量成正比，与枯落物量成反比，它们之间的幂函数关系非常密切．枯落物与苔藓组合层对径流速度的阻延效果比仅有枯落物层更明显  相似文献   

GROWTH OF PRIMULA PLANT IN COIR DUST AND PEAT-BASED GROWING MEDIA     

S. Bagci  G. Cayci  C. Kütük 《Journal of plant nutrition》2013,36(6):909-919

This study was performed under greenhouse conditions, with coir dust, moss peat, and sedge peat as the main components of the growing media. The performance of the media was evaluated through the growth of the primula (Primula obconica) plant. In general, aeration capacities were found to be relatively low, except for growing media that included moss peat mixtures. Nevertheless, easily available water content of all growing media was found to be within the appropriate ranges. Total and water-available plant nutrient contents of coir dust, moss peat, and sedge peat significantly fluctuated. Ornamental parameters related to media treatments were statistically significant, with respect to visual score performances, total leaf numbers, crown width, and total plant fresh weights. This study determined that coir dust, which is an industrial by-product, could be utilized for up to 50% of the total composition of coir dust-moss peat based media in floricultural aims. As floricultural quality parameters considered, 50% coir dust and 50% moss peat and 25% coir dust and 75% moss peat gave good results as much as 100% moss peat.  相似文献   

Contents of heavy metal elements in copper mosses: Scopelophila ligulata,Scopelophila cataractae,and Mielichhoferia japonica and their substrates     

Yoshio Aikawa  Iwao Nagano  Shunjiro Sakamoto  Masaya Nishiyama  Satoshi Matsumoto 《Soil Science and Plant Nutrition》2013,59(4):835-842

Scopelophila ligulata (Spruce) Spruce, S. cataractae (Mitt.) Broth., and Mielichhoferia japonica Besch. (Mielichhoferia mielichhoferi (Hook.) Wijk et Marg. var. japonica (Besch.) Wijk et Marg.) are well known “copper mossess” which show peculiar ecological characteristics consisting of a preference for metal-rich soils, lithosols, rocks, etc. as their substrates. The total and water-soluble element contents in the substrates and heavy metal contents in the moss body were analyzed in this study. The results of these chemical analyses were as follows: The iron contents in the moss body and substrate of S. ligulata were higher than those of S. cataractae and M. japonica. On the contrary the copper contents of the former were lower than those of the latter. The pH values of substrate of S. ligulata were lower than those of S. cataractae and M. japonica. The concentrations of water-soluble iron and sulfate in the substrate of S. ligulata were higher than those of S. cataractae and M. japonica. On the contrary, the water-soluble copper concentrations in the substrate of S. ligulata were lower than those of the others. Although in the substrate of S. cataractae the iron content was several times higher than the copper content, in the moss body the copper content was higher than iron content.  相似文献   

Shrub modulates the stoichiometry of moss and soil in desert ecosystems,China     

Yonggang LI 《干旱区科学》2019,11(4):579-594

Desert mosses, which are important stabilizers in desert ecosystems, are distributed patchily under and between shrubs. Mosses differ from vascular plants in the ways they take up nutrients. Clarifying their distribution with ecological stoichiometry may be useful in explaining their mechanisms of living in different microhabitats. In this study, Syntrichia caninervis, the dominant moss species of moss crusts in the Gurbantunggut Desert, China, was selected to examine the study of stoichiometric characteristics in three microhabitats (under living shrubs, under dead shrubs and in exposed ground). The stoichiometry and enzyme activity of rhizosphere soil were analyzed. The plant function in the above-ground and below-ground parts of S. caninervis is significantly different, so the stoichiometry of the above-ground and below-ground parts might also be different. Results showed that carbon (C), nitrogen (N) and phosphorus (P) contents in the below-ground parts of S. caninervis were significantly lower than those in the above-ground parts. The highest N and P contents of the two parts were found under living shrubs and the lowest under dead shrubs. The C contents of the two parts did not differ significantly among the three microhabitats. In contrast, the ratios of C:N and C:P in the below-ground parts were higher than those in the above-ground parts in all microhabitats, with significant differences in the microhabitats of exposed ground and under living shrubs. There was an increasing trend in soil organic carbon (SOC), soil total nitrogen (STN), soil available phosphorous (SAP), and C:P and N:P ratios from exposed ground to under living shrubs and to under dead shrubs. No significant differences were found in soil total phosphorous (STP) and soil available nitrogen (SAN), or in ratios of C:N and SAN:SAP. Higher soil urease (SUE) and soil nitrate reductase (SNR) activities were found in soil under dead shrubs, while higher soil sucrase (STC) and soil β-glucosidase (SBG) activities were respectively found in exposed ground and under living shrubs. Soil alkaline phosphatase (AKP) activity reached its lowest value under dead shrubs, and there was no significant difference between the microhabitats of exposed ground and under living shrubs. Results indicated that the photosynthesis-related C of S. caninervis remained stable under the three microhabitats while N and P were mediated by the microhabitats. The growth strategy of S. caninervis varied in different microhabitats because of the different energy cycles and nutrient balances. The changes of stoichiometry in soil were not mirrored in the moss. We conclude that microhabitat could change the growth strategy of moss and nutrients cycling of moss patches.  相似文献   

我国干旱沙漠地区不同类型土壤结皮的理化性质研究   总被引：3，自引：1，他引：2  

陈小红  段争虎 《干旱区资源与环境》2008,22(9)

本研究对我国干旱沙漠地区不同类型土壤结皮的理化性质特征进行了系统研究。研究结果表明:无论是不同地区还是同一地区不同发育程度的土壤结皮机械组成,它们的共同特征都是砂粒和粗粉粒含量相对较多,细粉粒和粘粒含量相对较少;从流沙到土壤结皮的形成过程中,粗粉粒是土壤结皮形成的关键基础。通过对同一地区不同发育程度的结皮机械组成比较说明结皮形成初期对颗粒组成有一定的要求,组成达到一定范围才能形成结皮,结皮一旦形成,随时间的增加,结皮厚度在不断增加,但质地基本不变。土壤结皮的形成过程是土壤养分和有机质不断富积的过程。各研究区的土壤结皮pH值相差不大,均在8左右,呈弱碱性;碱化度均≥5,处于碱化发育过程中。由于各地降水量和土壤母质发育的不同,不同地区以及同一地区不同发育程度的土壤结皮之间的CaCO3含量差异较大;同一地区土壤结皮的全盐量差异不大;不同地区土壤结皮的阴阳离子交换量差异较大,同一地区之间差异不大。该文对进一步研究土壤结皮的形成有一定的参考价值。  相似文献   

生物土壤结皮物理因子对植物种子萌发的影响     

邵晨曦  秦树高  冯薇  魏宝 《中国农业大学学报》2016,21(2):20-30

本研究采用冗余分析的方法,探讨了生物土壤结皮物理性质对小麦Triticum aestivum L.、黑豆Glycinemax merr L.、白菜Brassica rapavar.glabra和软尾生菜Lactuca sativa萌发的作用。结果显示:1)在结皮上表面:生物土壤结皮的厚度对4种植物种子萌发率均有反作用(P0.05,n=5);生物土壤结皮的抗压强度抑制软尾生菜的萌发率呈负相关(P0.05,n=5);生物土壤结皮的厚度与黑豆种子平均萌发时间呈正相关(P0.05,n=5)。2)在结皮下表面:生物土壤结皮的孔隙度和分形维数与小麦的萌发率呈正相关(P0.05,n=5);生物土壤结皮的厚度抑制了黑豆和白菜的萌发率(P0.05,n=5);生物土壤结皮的抗压强度对黑豆和软尾生菜萌发率起反作用(P0.05,n=5);生物土壤结皮容重的增加降低了小麦的萌发速率(P0.05,n=5);生物土壤结皮厚度增加减慢了黑豆、白菜和软尾生菜的萌发速率(P0.05n=5);生物土壤结皮抗压强度的增加降低了黑豆和白菜的萌发速率(P0.05,n=5)。结果表明,在结皮上表面,结皮厚度对4种植物种子萌发率均起抑制作用,尤其能够减慢胚根较为粗壮的黑豆种子的萌发速率。在结皮下表面,胚芽尖细的小麦可以利用结皮孔隙萌发;黑豆、白菜和软尾生菜由于子叶较大,不能利用生物土壤结皮的孔隙,其萌发率和萌发速率主要受生物土壤结皮的厚度或抗压强度抑制。  相似文献   

Microalgal species variation at different successional stages in biological soil crusts of the Gurbantunggut Desert,Northwestern China   总被引：1，自引：0，他引：1  

Bingchang Zhang  Yuanming Zhang  Jiancheng Zhao  Nan Wu  Rongyi Chen  Jing Zhang 《Biology and Fertility of Soils》2009,45(5):539-547

Biological soil crusts (BSC), most notably lichen crusts, develop and diversify in the Gurbantunggut Desert, the largest fixed and semi-fixed desert in China. Four different successional stages of BSC, including bare sand, microalgal crusts, lichen crusts, and moss crusts, were selected to determine successional changes in microalgal species composition and biomass and formation of BSC. A 10 × 10-m observation plot was established in an interdune region of the Gurbantunggut Desert and data were collected over an 8-year study period. The main results were: (1) different successional stages of BSC significantly affected the content of soil organic C and total and available N but not the total and available P and K content of soil; (2) composition of microalgal communities differed among the four successional stages; (3) significant differences in microalgal biomass were observed among the four successional stages; (4) bare sand was mainly uncompacted sand gains; (5) filamentous cyanobacteria, particularly Microcoleus vaginatus, were the dominant species in the early phase of crust succession. The presence of fungal mycelium and moss rhizoids prevented water and wind erosion.  相似文献