Agricultural production model adapt to climate change based on indigenous knowledge of ethnic minorities in Bac Kan province, Vietnam

Tran Van Dien and Dam Xuan Van

Indigenous knowledge and practices were investigated in the local communities that have been severely affected by the impacts of climate change in recent years in Bac Kan province. The manifestation and impact of climate change to agricultural production and livelihood of local people were identified and clarified in this area. Indigenous knowledge and practices in prediction, response and adaptation to extreme weather phenomena and climate change for agricultural production of the local communities were clarified and documented. Findings from the study showed that ethnic minority groups in the research area have a lot of indigenous knowledge and practices in agriculture production copping with extreme weather phenomena and climate change. Various local cultivars which are resistant to drought and cold are used by local ethnic minorities such as banana (Tay variety), rice (Bao Thai), mungbean (moc), local ginger cultivar and potato. Therefore banana, potato, ginger and mungbean are recommended for farmers in the Bac Kan province to grow as crops adapting to climate change. Many traditional practices in agriculture production coping with drought and cold conditions were also investigated such as indigenous practices in banana cultivation on sloping land; appropriate arrangement of the crop growing season in accordance with climate change conditions; weather forecast based on symptoms of natural condition etc. The study also reviewed agricultural policies relating to climate change at all levels and found that there was a big gap between current government policies with real problems occurred in the field due to climate change.

Methodology for erosion risk zoning in the city of Brazzaville study of case in the urban area

Kempena Adolphe, Bilembi David, Boudzoumou Florent, and Nganga Dominique

The erosion phenomenon produces severe damages in the city of Brazzaville. Although it is difficult to stop it at a local scale, their after-effects can be mitigated. The forward-moving urban border in the steep terrains of the natural space, causes forest and savannah disappearance. This forest and savannah reduction causes intense soil erosion processes that conduct to a poor vegetative cover and increase the level of surface drainage capacity. The lack of an appropriate cartography makes difficult land use planning in the city of Brazzaville. This work takes into account an erosion risk model based on georeferred data which is easier to reproduce in developing countries with a few number of available cartographic layers. Slope, land cover/land use and soils are analyzed to establish the cartography model for erosion risk. This cartography showed areas occupied by different classes of erosion risk.

Effects of drilling deep tube wells in the urban areas of Nairobi city, Kenya

Caroline Onyancha, Eliud Mathu, Sixtus Mwea and Wilson Ngecu

The number of boreholes for abstracting water from aquifers beneath Nairobi City increased from 2 in the year 1927 to about 2500 in the year 2009. According to the Republic of Kenya Population and Housing Census, the urban population of Nairobi City increased from 29,864 in 1928 to 3,138,295 in 2009. Substantial groundwater drawdown has been noted in individual boreholes that supply the growing population in some localities. The purpose of this study was to investigate the variation in water rest levels across Nairobi City during the 80 year period and estimate the surface settlement that can result from groundwater exploitation. The groundwater static level variations in space and time were analysed on Surfer 9 software and the average rest levels in boreholes between 1927 and 2009 were calculated. Using the hydrogeological data obtained from drilling, an estimate of ground settlement that could result from continuous drawdown was made from formulae obtained from past studies done elsewhere. The results indicate that that the groundwater rest levels have dropped with an average of 79 m in the last 80 years and a probable settlement of 0. 34 m to 5.9 m could result from groundwater depletion from aquifers and clay aquitards over a long period of time. Between the ground surface and the clay aquitards are the dense Nairobi Phonolite and/or Nairobi Trachyte. The probable settlement of 5.9 m should serve as a wakeup call to put up measures that can mitigate subsidence and the related consequences in Nairobi City. Indeed, 67% of the drop in rest levels has occurred in the last two decades during which more than 1000 additional wells have been drilled.

Reduced fluids in the crystalline basement and the sedimentary basin (on an example of Romashkin and Verkhne-Chonskoye oil fields)

Rimma P. Gottikh, Bogdan I. Pisotskiy and I. N. Plotnikova

The paper considers geochemical data on the composition of the reduced fluids that have been found to penetrate the rocks of crystalline basement and sedimentary cover of two regions of the two ancient platforms - East European and Siberian. The study was based on the detailed petrographic research, a wide range of up-to-date geochemical and nuclear physical methods to study the fluid impact on the geological medium, such as thermobarogeochemical, chromatographic, mass spectrometric, bitumen, f-radiographic, instrumental neutron activation and other analyses. The studies have shown that the above fluid systems, which penetrate into the sedimentary rocks from the crystalline basement in petroleum areas, are the complex, multicomponent systems, transporting the elements of lithophilous, chalcophilous and siderophilous groups, which differ in affinity to oxygen and sulphur. Associations of elements in the fluids can only be maintained by organic ligand complexes that permit the transportation of metals over considerable distances through the geological medium. The acquired geochemical and thermodynamic characteristics of the reduced fluids and their differentiation products from the crystalline basement and the sedimentary cover of the southern Siberian and eastern part of the East European platforms indicate that these were formed outside of the sedimentary cover and that the migration was directed upwards.