Distribution characteristics and influencing factors of soil organic carbon in alpine ecosystems on the Tibetan Plateau transect, China

The undisturbed regions along the Qinghai-Tibet Highway crossing the natural zones of montane desert, alpine meadow-steppe, and montane shrub-coniferous forest were chosen as the study areas. Soil samples were collected at 23 sites and the relations between the influencing factors and distribution of soil organic carbon (SOC) content were studied. The results indicated that the order of SOC content for the whole soil profile with different vegetations and in the horizontal direction was shown as below: forest>shrub>meadow>steppe>desert. All the SOC contents of the top 10 cm soil layers of forest, shrub and meadow vegetations, as well as that of the top 20 cm soil layers in steppe, in the vertical direction, were higher than those of corresponding lower soil layers. However, the SOC content in the desert soil was in accordance. The grey correlative analysis between the climatic factors and SOC content in the top soil show that precipitation was the dominant climatic factor affecting the distribution of SOC in the Tibetan Plateau transect. The influence of precipitation on the horizontal distribution of SOC decreased with the increase of precipitation in the horizontal direction. The vertical distribution of SOC along the soil profile was greatly affected by precipitation or the soil clay content in top soil layers, and was clearly influenced by soil silt content or sand content in lower soil layers, as well. The influences of both soil bulk density and soil pH on the vertical distribution of SOC along the soil profile gradually declined. The plant biomass was the most important biotic factors affecting the distribution of the SOC. __________ Translated from Journal of Zhejiang University (Agriculture & Life Sciences), 2007, 33(4): 443–449 [译自: 浙江大学学报(农业与生命科学版)]     

白绒山羊生态舍饲养殖模式浅见

研究了传统放牧饲养方式和简单圈养方式的利与弊,根据北方养殖现状,提出了高效生态养殖的思路和实施方法。     

中国茶园生态系统资源价值的估算

本文以自然资源价值论为基础估算了中国茶园生态系统的资源价值,文中对茶园生态系统的直接生产价值、社会保障功能、有机物积累、营养物质循环、水源涵养、土壤固持、气体调节和文化价值及茶树种植过程的负面环境功能一一作出估算,最后得到中国茶园生态系统的服务价值总量为1301.7364亿元.     

Molecular complex of lignosulfonic acid/poly(vinyl pyridine) via ionic interaction: characterization of chemical composition and application to material surface modifications

Poly ion complexes of anionic lignosulfonic acid (LSA) with cationic poly(2-vinyl pyridine) or poly(4-vinyl pyridine) were prepared by mixing the polymer solutions in dimethyl sulfoxide or dilute hydrochloric acid. The complexes were formed as soon as the polymer solutions were mixed. Fourier transform infrared (FTIR) measurements for the complexes revealed the presence of strong ionic interactions between sulfonate anions of LSA and pyridinium cations of the vinyl pyridine (VPy) polymers. The strong interaction was supported by detection of a glass transition temperature (T _g) much higher than pristine T _g values of VPy polymers in differential scanning calorimetry. By using the ionic complexation, a coating of LSA onto VPy polymer films was undertaken to modify their original surface property. Formation of a thin complex film was confirmed by observation of absorption bands that are characteristic of the pyridinium cation in reflection FTIR spectra measurements, and by visualization of the attached LSA component in atomic force microscopy. This treatment resulted in the surface of the VPy polymer films becoming hydrophobic. An adhesion test was also conducted by pasting two veneered woods with the polymer complex, followed by shear-tearing them off. The adhesive strength of the complex was estimated to be 1.1 MPa. Part of this report was presented at the 55th (Kyoto, March 2005) and 56th (Akita, August 2006) Annual Meetings of the Japan Wood Research Society     

北京市市级森林生态系统自然保护区现状及发展对策

自1985～2000年,北京市建立市级森林生态系统类型自然保护区7个,总面积75 862 hm2.它们在开展保护监测、科学研究、教育培训、生态旅游等方面做了大量工作.目前还存在着权属不统一、人员无编制、经费投入不足、科技力量薄弱、法规不完备等问题,据此提出了若干发展对策.     

土壤吸附作用对土壤水分有效性的影响

围绕土壤结皮生物是否可以对夜间土壤吸附水输入产生响应展开研究。假定-1.5 MPa作为土壤水分有效性的临界值,通过观测降水后清晨和午后0~3 cm土壤含水量,分析土壤水分的有效性和空间异质性;并利用连续记录气象数据,建立表层土壤含水量与水汽压饱和差数量关系。结果表明:土壤吸附作用提高了土壤水分对土壤结皮生物的有效性,并延长了土壤结皮生物对降水脉冲的响应时段。在古尔班通古特沙漠东南部的不同部位,凝结吸附作用对沙面水分条件影响很大(特别是干旱季节),水分条件由好到坏依次为:沙垄西坡面、沙垄垄顶、沙垄东坡面和垄间低地。     

洋葱伯克氏菌群不同基因型菌株对几种重要植物病原真菌的抑制作用及其潜在致病性

从玉米和水稻根围分离到70株不同基因型的洋葱伯克氏菌,对这些菌株进行了拮抗植物病原菌的筛选,并对高拮抗菌株进行了潜在致病性和安全性分析。结果表明,有46株洋葱伯克氏菌对一种或多种病菌有较高的拮抗活性。在不同的洋葱伯克氏菌基因型内,以基因型Ⅴ内拮抗菌株占的比例最高,对所测5种病原真菌的平均拮抗菌株比率为80．0％,其中部分菌株表现出很强的拮抗活性。筛选出的4株高拮抗菌株对洋葱不具有致病性,同时也未检测到与人体致病相关的BCESM毒力基因。     

混合盐碱胁迫对燕麦种子萌发及幼苗生理生化特性的影响

为了探讨燕麦种子和幼苗的耐盐碱能力及在盐碱胁迫下的变化规律,采用纸上发芽法和砂培法,研究了混合盐碱胁迫对燕麦种子萌发及幼苗生理生化特性的影响.结果表明:随着盐碱胁迫浓度的增强,燕麦种子的发芽率、发芽指数、活力指数和幼苗生长与对照相比都呈下降趋势;而燕麦叶片中细胞膜透性增强和丙二醛含量增加,其中白燕1号较白燕7号增加幅度大,表明白燕1号比白燕7号对盐碱胁迫更敏感,受盐碱危害程度较重;同时燕麦叶片内游离脯氨酸和可溶性糖累积,且随着盐碱胁迫浓度的增强呈增大趋势,其中白燕7号增加幅度大,表明白燕7号可能主要通过积累脯氨酸和可溶性糖来进行渗透调节缓解逆境毒害作用,其中白燕1号在盐碱胁迫浓度100～200 mmol/L时,游离脯氨酸和可溶性糖含量下降,但其机理还有待于进一步研究.综合分析表明两个品种耐盐碱能力为:白燕7号＞白燕1号.     

旱地生态系统生态流与价值流耦合途径的研究

在界定了旱地生态系统基础上,阐述了旱地生态系统的物质流、能量流、信息流和价值流的基本特征,分析了制约旱地生态系统生态流与价值流耦合的主要因素,提出了实现旱地生态系统生态流与价值流耦合的基本途径。     

杨柳树在长春市街路广场园林生态系统中的地位研究

利用样地调查方法,对长春市街路与广场的树木结构进行分析,结果表明：街路与广场共有杨柳树172617株,杨树的平均胸径为19．8cm,平均树高8．5m;柳树的平均胸径为20．0cm,平均树高7．5m。杨柳树的总生物量为83805．5t,总叶面积为14851196．9m^2。杨柳树每年可以制造干物质4629．2t,吸收二氧化碳6786．6t,放出氧气4939．4t,吸滞灰尘5755．4t,吸收二氧化硫44．1t。