Management Options to Conserve and Sequester Carbon in the Agricultural Sector of the Former Soviet Union

Several management practices are available to conserve and sequester C in the agricultural sector of the former Soviet Union (FSU). The highest rate of C accumulation would result from the implementation of a no-till management option which will only continue during the first ten years until new C equilibrium is reached. Agroforestry management options provide a longer period for C accumulation, but at a lower rate. It is possible that the longest period of C conservation may be achieved by increasing the area under perennial grasses in the crop rotation. During the first decade of implementation of the management practices, the amount of C conserved or sequestered would be approximately equal to the current rate of net C sequestration in FSU forest sector. At present, agricultural soils and vegetation of the FSU store approximately 120 Pg C; the accumulation of soil organic matter is 0.032 Pg C yr^-1. The annual C loss in the FSU agricultural sector was estimated at 0.21 Pg C yr^-1.     

肯尼亚退化红树林港湾悬浮泥沙交换和输移动力机制

本文主要研究了肯尼亚姆瓦彻湾(属于浅潮滩红树林湿地)泥沙交换的动力机制.该港湾属于半日潮,大、小潮的潮差分别为.2m和1.4m,大潮高水位的水面面积为17km2.     

An approach to the fluctuation mechanism of ecotone

In this paper,the relationship among land productivity,population pressure and the fluctuation mechanism of ecotone is analyzed,taking coumties and banners of southeast Inner Mongolia plateau as an example,which is the most fragile part in the farming and husbandry interleaving belt of north China due to its severe desertification degree and low level of economic development.The Cv for the total output value of agriculture decreases from southeast to northwest,with the same rule as which the overloading population cumulated distributes,and both indicators have close relation with the high linear coefficient of 0.83.These reveal the fluctuation mechanism for ecotone:fluctuation of the level of economic development is a scientific and practical measure both to weakness degree and to instability of ecotone,because it is a synthesized response to the variation of climate as well as irrational land uses,which reinforce and magnify the fluctuation.In detail,the heavier the population overloading,the severer the grassland reclamation,the stronger the dependence of regional productivity on rainfall,the lower the level of economic development,the rougher the fluctuation of ecotone,but the weaker the PRED system.     

Strategies of a bark beetle, Pityogenes bidentatus, in an olfactory landscape

 Volatiles from leaves or bark of nonhost birch (Betula pendula) and Norway spruce (Picea abies) dramatically reduced the attraction of the bark beetle, Pityogenes bidentatus (Coleoptera: Scolytidae), to their aggregation pheromone components (cis-verbenol and grandisol) in the field. In addition, odors from both the needles and bark of the host Scots pine (Pinus sylvestris) similarly inhibited attraction. Monoterpenes of pine and spruce (α-pinene, β-pinene, terpinolene, and 3-carene) as well as ethanol, chalcogran and some nonhost green leaf alcohols [(Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, and 1-hexanol], also reduced catches. Collections of volatiles from the field-tested plant tissues indicated they released monoterpenes in amounts similar to the synthetics that inhibited responses. The various plant and insect sources of these inhibitory compounds indicate that P. bidentatus bark beetles have evolved several strategies to increase their fitness by avoiding nonhost and unsuitable host trees in a complex olfactory landscape. Received: 6 June 2000 / Accepted in revised form: 25 September 2000     

Regulation of hepatocyte proliferation

After partial hepatectomy the low proliferation rate of hepatocytes increases dramatically. This is based on a feed-back system whose central link is a liver cell proliferation hormon, the so-called hepatopoietin. The hormon originates from the Peyer's patches: after their resection, the liver cell proliferation after partial hepatectomy decreases by about 80%. Hepatopoietin effects organ specific but species nonspecific.