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Denitrification Rates and Their Controlling Factors in Streams of the Han River Basin with Different Land-Use Patterns

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Pedosphere 2014年第4期24卷 516-528页

作者： S.P.JUNG Y.J.KIM H.KANG School of Civil and Environmental Engineering Yonsei UniversitySeoul 120-749(Korea) River and Coastal Research Division Korea Institute of Construction TechnologyGoyang 211-712(Korea)

Land-use patterns can affect various nutrient cycles in stream ecosystems, but little information is available about the effects of urban development on denitrification processes at the watershed scale. In the presented study, we investigated the controlling factors of denitrification rates within the streams of the Han River Basin, Korea, with different land-use patterns, in order to enhance the effectiveness of water resource management strategies. Ten watersheds were classified into three land-use patterns （forest, agriculture and urban） using satellite images and geographic information system techniques, and in-situ denitrification rates were determined using an acetylene blocking method. Additionally, sediment samples were collected from each stream to analyze denitrifier communities and abundance using molecular approaches. In-situ denitrification rates were found to be in the order of agricultural streams （289.6 mg N20-N m-2 d-1）〉 urban streams （157.0 mg N20-N m-2 d-1）〉 forested streams （41.9 mg N20-N m-2 d-l）. In contrast, the average quantity of denitrifying genes was the lowest in the urban streams. Genetic diversity of denitrifying genes was not affected by watershed land-use pattern, but exhibited stream-dependent pattern. More significance factors were involved in denitrification in the sites with higher denitrification rates. Multiple linear regression analysis revealed that clay, dissolved organic carbon and water contents were the main factors controlling denitrification rate in the agricultural streams, while dissolved organic carbon was the main controlling factor in the urban streams. In contrast, temperature appeared to be the main controlling factor in the forested streams.

关键词： denitrifier communities denitrifying genes nutrient cycle stream ecosystem

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STUDIES ON STRUCTURE AND FUNCTIONS OF MONGOLIAN OAK FORESTS

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Journal of Northeast Forestry University 1995年第3期6卷 65-70页

作者：王传宽桑运荣鲍淳松 Northeast Forestry University Harbin 150040 P.K. China

After the investigation and long-lerm research, the structure, succession, energy flow,nutrient and water cycles, produetivity, ete. of Mongolian oak (Quercus mongolica) forest ecosysteins are synthetically summarized. The oak, with a simple stand composition, naturally distributes at hilltops, where the soil is arid and inlfertile and lots of tree species can not grow, and stabilizes for a long period for its high adaptive capacity and long longevity, but it will grow better in good *** with other forest ecosystems in temperate zone, the oak forest has not only more intensive biological cycles of nutrients but higher productivity as well. Among the nine elements determined, the concentrations of Ca and Zn are the highest and lowest, amounling to 41 .99% and 0.0015%, respectiveiv. In the vegetation, the largest nutrient pool is root svstem, making up 47.75%, and the trunk steps the following, 25. 13%. Among the main secondary forest types in Maoershan region, the oak stands have not only highest biomass but best biomass structure for in which the biomass of trcc stratum reaches 95.6% of the total of the stands and that of trunk does 68.9% of the total of the tree. The oak stands have high steinflow, which amounts to 15.6% of the precipitation and carries a lot of nutrients, and high evapotranspiration, which is as high as 504. 1 mm and for which 77.45% of the total radiation (123.3 KJ. cm-2) is consumed as latent heat transter in the growing reason. The clearcutting of the oak stands will result in not only inereasing the surlace runoff and interflow percentage but also intensitying the loses of N, Ca, Mg and Fe. Finally, it is proposed to pay a great attention to *** and even planting the oak as high yield timber and water conservation forests.

关键词： Mongolian oak Structure Energy flow nutrient cycle Water cycle Productivity

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Heavy Metals in Agricultural Soils of Central Ethiopia: The Contribution of Land Use Types and Organic Sources to Their Variability

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Open Journal of Soil Science 2016年第6期6卷 99-112页

作者： Nigatu Alemayehu Minase Mary M. Masafu Abule Ebro Geda Azage Tegegne Wolde International Livestock Research Institute Addis Ababa Ethiopia University of South Africa Pretoria South Africa

In the present study, about 94% of the arable land had a phosphorus deficiency (available P ·kgǃ). To compensate for this deficiency, high amounts of phosphorous fertilization were applied to soils to get better crop yield. In the past two decades, soil organic matter has sharply declined from 34.8 g/kg in late 1980s’ to 12.0 g/kg in 2010. The soil has moderate to high cation exchanging capacity (CEC) in the range of 45 - 58 Meq/100 gm. The low soil organic carbon, high CEC and high phosphorus fertilization could lead to poor heavy metal availability to plants. Nevertheless, DTPA extractable concentrations were 40.5 mg/kg for copper, 35.5 mg/kg for iron, 134 mg/kg for manganese, 2.1 mg/kg for nickel, 2.6 mg/kg for lead and 53.5 mg/kg for zinc. All the available micronutrients seem to be adequate for plant growth. In terms of toxicity, the values of Cu, Fe, Mn, Zn, Ni and Pb found in the present investigation were lower than those of above critical value set by the international guidelines and other researchers. Variations in heavy metal content in the soil were attributed due to differences in land use types and disparity in organic sources amongst the plant and animal composites. For better crop productivity, more organic matter should be added to the soils. The traditional nutrient cycling practices, such as manure application, allow crop residue to decay on fields, fallowing and rotational cropping has to be followed to rehabilitate the soil and buildup both macro-and micro-nutrients to their natural level.

关键词： Phosphorous Toxicity Micronutrients Organic Carbon nutrient cycle

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Coffee Agroforestry with Some Timber Shade Trees： Study on Carbon Stock, Mineral cycle, and Yield

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Journal of Agricultural Science and Technology(B) 2011年第8期1卷 1232-1237页

作者： A. A. Prawoto F. Yuliasmara Indonesian Coffee and Cocoa Research Institute （ICCRI） PB. Sudirman 90 Jember Indonesia

Coffee cultivation by using shade trees is simple of agroforestry, this system could get better ecosystem service and sustainable agricultural. The aims of this research are to study the possibility of some species of industrial woods as shade trees of Coffea canephora. The research was conducted in Jember, Indonesia （45 m asl., D rainfall type according to Schmidt and Ferguson）, and arranged in split plot design. The main plots were （A） coffee-T, grandis （3 m × 2.5 m ×12 m）, （B） coffee-P, falcataria single row （2.5 m ×6 m）, （C） coffee-P, falcataria double rows （3 m× 2.5 m × 12 m）, （D） coffee-P, falcataria vat. Solomon （3 m× 2.5 m × 12 m）, （E） coffee-M, azedarach （3 m ×5 m ×22.5 m）, （F） coffee-H, macrophyllus （3 m ×5 m ×12.5 m）, and （G） coffee-Leucaena sp. （3 m × 2.5 m） as control. The sub plots were coffee clones, i.e., BP 534, BP 409, BP 936, dan BP 939. Among those timber trees, Leucaena was planted as the alternative shade trees. The result showed that in comparison with control, all of coffee agroforestry system improved carbon sequestration. Total C-stock on （B） was highest, i.e., 1,007 percent to control while the lowest one was （A） 317.44% to control. During one year observation, litter weight of H. macrophyllus was heaviest followed by T. grandis. The lightest litter was obtained from M. azedarach. Based on its mineral contents, litters of T. grandis potentially supplied back nutrients that equaled to total Urea, SP-36, KC1, Dolomite, and Kieserite as much as 574.14 g; P. falcataria 287.57 g, P. falcataria var. Solomon 453.59 g, M. azedarach 450.84 g, H. macrophyllus 877.56 g, and Leucaena 445.12 g per tree per year. Because of heavily fallen leaves of M. azedarach during dry season and conversely too dense shading of H. macrophyllus, bean yield at 4 and 5 years old by using both species were consistently lower than that under T. grandis, P. falcataria and control. At those ages, effect of clone on cherry yield was still not consistent but there was a tende

关键词： Coffea canephora agroforestry C-sequestration nutrient cycle yield.

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