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Jean de la Paix Mupenzi Lanhai Li Jiwen Ge Achal Varenyam Gabriel Habiyaremye Nzayisenga Theoneste Kamanzi Emmanuel 《地学前缘(英文版)》2011,2(4):599-607
This study has focused on the processes of soil degradation and chemical element concentration
in tea-growing regions of Rwanda, Africa. Soil degradation accelerated by erosion is caused not only
by topography but also by human activities. This soil degradation involves both the physical loss and
reduction in the amount of topsoil associated with nutrient decline. Soil samples were collected from
eleven tropical zones in Rwanda and from variable depth within each collecting site. Of these, Samples
from three locations in each zone were analyzed in the laboratory, with the result that the pH of all soil
samples is shown to be less than 5 (pH < 5) with a general average of 4.4. The elements such as iron (Fe),
copper (Cu), manganese (Mn), and zinc (Zn) are present in high concentration levels. In contrast calcium
(Ca) and sodium (Na) are present at low-level concentrations and carbon (C) was found in minimal concentrations. In addition, elements derived from fertilizers, such as nitrogen (N), phosphorous (P), and
potassium (K) which is also from minerals such as feldspar, are also present in low-level concentrations.
The results indicate that the soil in certain Rwandan tea plantations is acidic and that this level of pH may
help explain, in addition to natural factors, the deficiency of some elements such as Ca, Mg, P and N. The
use of chemical fertilizers, land use system and the location of fields relative to household plots are also
considered to help explain why tea plantation soils are typically degraded. 相似文献
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Analysis of snowmelt model for flood forecast for water in arid zone: case of Tarim River in Northwest China 总被引：1，自引：1，他引：0
Mupenzi Jean de la Paix Li Lanhai Ge Jiwen Habumugisha Jean de Dieu Nzayisenga Theoneste 《Environmental Earth Sciences》2012,66(5):1423-1429
Field studies were carried out in Tarim River Basin, Northwest China for analysis of snowmelt model for flood forecast for a river in arid zone. Snow is a major source for water availability in arid zone of Northwest China where 50% of snow cover withdrew by sublimation during dry and cold climatic condition. The analysis of weekly forecast of daily discharges was helped by the temperature index model, ARIMA model for temperature and flow, D-IUH runoff model and D-IUH model estimation where the temperature forecast was used as driving variable; the numerical simulations were carried out using SUSA® software for testing the sensitivity of the D-IUH to the input values of the parameter and an analysis of the forecast results against the set of input parameters resulted in a determination coefficient R 2 = 0.5. The standard deviation was 3.28 and the mean for the Tarim River was 5.37 (mm d?1) implying that the forecasted data is in strong agreement with the observed data. The combination of methods is better useful for calculation in order to avoid errors of appreciation. 相似文献
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