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Search Results: 1 - 10 of 4670 matches for " semi-arid areas "
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Efecto del riego con aguas residuales sobre propiedades químicas de suelos de la planicie de Coro, Estado Falcón
Zamora,Frank; Rodríguez,Nectali; Torres,Duilio; Yendis,Héctor;
Bioagro , 2008,
Abstract: with the purpose of determining the potential use of wastewaters as alternative for irrigation in the semi-arid areas of falcon state, it was evaluated the effect on chemical properties of soils in three production zones located in the coro plains: one under permanent irrigation of pasture, other with intermittent irrigation of vegetables, and an area of virgin soils without use of wastewaters. results showed that the permanent use of wastewater on pasture improved soil fertility because it led to increments in the organic matter, p, k, and mg contents. however, the continuous use of the wastewater increased the soil content of cadmium and lead at levels that could be harmful to health due to probable crop contamination with heavy metals.
Trace Element Concentrations in Some Traditional Diets Consumed in Selected Parts of Eastern Province of Kenya  [PDF]
David M. Maina, Lydia W. Njenga, John M. Onyari, Benjamin N. Kyalo
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.37075
Abstract: Dietary quality is vital in maintaining sound nutritional status. The ecological conditions thus influence the type of diets and their nutritional quality. The purpose of this study was to determine the trace element/mineral content of some of the commonly consumed diets in Machakos, Kitui, Makueni and Mwingi districts. Decorticated maize, beans and finger millet flour samples were purchased from the local markets. For each category, a total of ten samples were collected from each district. The samples were put in plastic bags, sealed and transported to the laboratory in the Institute of Nuclear Science & Technology, University of Nairobi for preparation and analysis. The cooking of the samples was carried out according to local traditional methods. In the decorticated samples, mean copper concentrations were observed to be below 20 μg·g-1; mean zinc concentrations ranged from 34 to 63 μg·g-1 and mean manganese concentrations were in a similar range of 34 to 78 μg·g-1. The mean iron concentrations were significantly high with a range of 161 μg·g-1 to 287 μg·g-1. A similar trend was observed in the beans where the mean copper concentrations varied from 11 to 33 μg·g-1, mean zinc concentrations ranged from a low value of 24 μg·g-1 to a high value of 35 μg·g-1, mean manganese concentrations varied from 33 μg·g-1 to 98 μg·g-1 and the mean iron concentrations ranged from 227 μg·g-1 to 647 μg·g-1. The cooked Muthokoi samples from Machakos district had relatively high mean trace element concentrations: manganese—109 μg·g-1; iron—280 μg·g-1; copper—19 μg·g-1; and zinc—41 μg·g-1. The only exception was mean iron concentrations which were extremely high in samples from Mwingi District where the concentrations varied from 73 μg·g-1 to 1597 μg·g-1. In finger millet flour, the mean manganese concentrations varied from 95 to 290 μg·g-1, whereas the mean iron concentrations ranged from 127 μg·g-1 to 259 μg·g-1. In contrast, the mean copper and zinc concentrations were low in comparison to the manganese and iron concentrations. As a whole, the mean copper concentrations in the diets are significantly low compared to the other three trace elements. However, the total content is not necessarily a reflection of the amount assimilated in the body. Finger millet was found to be an excellent source of manganese and iron whereas beans were observed to be
Effects of Hydrogels on Soil Moisture and Growth of Cajanus cajan in Semi Arid Zone of Kongelai, West Pokot County  [PDF]
Cheruiyot Gilbert, Sirmah Peter, Ng’etich Wilson, Mengich Edward, Mburu Francis, Kimaiyo Sylvester, Bett Erick
Open Journal of Forestry (OJF) , 2014, DOI: 10.4236/ojf.2014.41006
Abstract:

Studies on the effects of hydrogels on soil amendments, moisture conservation and growth of Cajanus cajan in arid and semi-arid lands were carried out. Seedlings of C. cajan were established both in the nursery and in the field with and without hydrogels. In the field, three replications were used with three levels of hydrogels concentration (7 g, 11 g, and 15 g). Control seedlings were established in soils without hydrogels. In the nursery, root collar diameters and heights were measured every two weeks up to eight weeks. Seedlings established without hydrogels in the nursery were transplanted into field soils with none, 7 g, 11 g and 15 g of hydrogels. Root collar diameters and heights were again measured every month for three months. In addition, soil was collected randomly once every month from the base of each seedling and analyzed for soil moisture using standard laboratory procedures. All data were subjected to analysis of variance. The results show that growth in both the height and root collar diameter of the species was

Properties of Solar Radiation over Chinese Arid and Semi-Arid Areas
干旱半干旱区太阳辐射特征

HU Bo,WANG Yue-Si,LIU Guang-Ren,
HU Bo
,WANG Yue-Si,LIU Guang-Ren

大气和海洋科学快报 , 2009,
Abstract: Climatic characteristics of broadband solar radiation (Rs) in Chinese arid and semi-arid areas are reported in this study. The annual average daily Rs in the arid and semi-arid areas is 16.3 ± 5.77 and 15.3 ± 5.16 MJ m 2 d 1, respectively. The highest value (17.2± 5.84 MJ m 2 d 1) appears in an arid area at Linze. The lowest value appears in the semi-arid area of Ansai. Pronounced seasonal variation of Rs is observed with the highest value in summer and the lowest in winter. The clearness index showed similar seasonal pattern at most sites, with the minimum observed in the summer and the highest values in winter at both arid and semi-arid areas. The seasonal variation of the ratio of Rs to its extraterrestrial value Kt in the arid area is more significant than that observed in the semi-arid region, and it is caused by the different range of variation of water vapor between arid and semi-arid areas. The seasonal fluctuations in Rs and Kt are mainly controlled by the water vapor content in these areas. The aerosol particles have significant influence on Rs and Kt at stations with higher aerosol burden.
Riparian Areas of Greece: Their Definition and Characteristics
G. N. Zaimes,V. Iakovoglou,D. Emmanouloudis,D. Gounaridis
Journal of Engineering Science and Technology Review , 2010,
Abstract: Riparian areas are unique and of high importance ecosystems because they are adjacent to surface freshwater bodies suchas streams, rivers and lakes. They are the semi-aquatic transitional zones (ecotones) between terrestrial and aquatic ecosystems.Water, soil and vegetation are the three main characteristics that differentiate them compared to other ecosystems.Furthermore, they are present in all biomes (from deserts to tropical forests) and are found in a great range of hydrologic andgeomorphologic conditions that results in a great variety of riparian habitat types. In Greece, there are five major riparianforest habitat types that also occur in most of the semi-arid Mediterranean regions. Frequent disturbance is another uniquecharacteristic that differentiates riparian areas. The major disturbances that shape riparian areas in Greece are unpredictedflood and drought events, as well as fires but to a lesser degree. Wetlands are another important semi-aquatic ecosystemsthat many consider as synonymous to riparian areas. In reality, these two ecosystems overlap but they are also different sincewetlands are considered as “wetter” and less disturbance driven than riparian areas.
Possible effects of changes in the meteorological state over semi-arid areas on the general well-being of weather-sensitive patients
Naomy S Yackerson, Ljuba Bromberg, Batiah Adler, Alexander Aizenberg
Environmental Health , 2012, DOI: 10.1186/1476-069x-11-26
Abstract: Under test was the group of 20 hypertensive weather-sensitive patients; their blood pressure, pulse rate and appearance of 4 symptoms of discomfort sensations: arthritic pain, unjustified anxiety, severe headache and inexplicable tiredness- were registered. Symptoms are classified in ICD-9 code (780–790) and scored on a 4-point scale. Results were defined as positive (no departure from the range of normal values) or problematic; the daily number of the latter results was collected under the name “pathological reactions” NPR if at least two of these 7 checked symptoms (of one patient) were outside the normal range. Comparison of the current weather conditions with their means, questioning of patients and repeated examinations are used to gain information. The data was analyzed employing the SAS statistical software. Pearson and Spearman correlations were used, applied on the best and worst days, when a minimum and a maximum of pathological changes NPR in the patients’ well-being were observed. The statistical significance was p?<?0.05 in all cases.~1500 medical observations and verbal statements were registered in the Primary Care Clinic (Be’er-Sheva, Israel) during 2001–2002. No meaning correlation was found between NPR and absolute values of temperature, humidity and atmospheric pressure. Variations in wind speed WS and direction were expressed in blood pressure changes and in exacerbation of discomfort of various degrees. Unfavorable conditions correspond to days with dominant desert air streams and to high WS, when NPR reaches 85.7%; during the days with prevalent sea breeze NPR was ≤22.9%. The role of wind direction in NPR occurrence is prevalent when WS?>?4?m·s-1. The Spearman test gives higher correlation than Pearson test (ρ?~?0.14, p?<?0.03 against ρ?~?0.1, p?<?0.04).NPR is more affected by the air streams than by absolute values of meteorological parameters. The method of this study might give to family doctors some additional tools to predict deterioration
Fungos micorrízicos arbusculares em bananeiras cultivadas no Vale do Submédio S?o Francisco
Melo, Adriana Mayumi Yano de;Maia, Leonor Costa;Morgado, Luiz Balbino;
Acta Botanica Brasilica , 1997, DOI: 10.1590/S0102-33061997000200003
Abstract: in the region of the s?o francisco valley, where irrigated agriculture is responsable for high production of fruits for exportation, banana is one of the most expanded crops in cultivated areas. in order to know the arbuscular mycorrhizal fungi associated with this crop, samples from the rhizosphere of banana plants were collected in four areas with different soil characteristics, being identified the species: acaulospora longula spain & schenck, a. morrowiae spain & schenck, a. rehmii sieverding & toro, a. scrobiculata trappe, a. spinosa walker & trappe, a. tuberculata janos & trappe, entrophospora infrequens (hall) ames & schneider, gigaspora ramisporophora spain, sieverding & schenck, glomus diaphanum morton & walker, g. etunicatum becker & gerd., g. intraradices schenck & smith, g. macrocarpum tui. & tui., g. mosseae (nicol. & gerd.) gerd. & trappe, g. occultum walker and scutellospora sp. the rate of colonization of banana roots by arbuscular mycorrhizal fungi in the investigated areas was around 55%.
The causes of land landscape changes in semi-arid area of Northwest China: a case study of Yulin city

GUO Liying,REN Zhiyuan,LIU Yansui,

地理学报 , 2006,
Abstract: Rapid land landscape change has taken place in many arid and semi-arid regions such as the vulnerable ecological area over the last decade. In this paper, we quantified land landscape change of Yulin in this area between 1985 and 2000 using remote sensing and GIS. It was found that fallow landscape decreased by 125,148 hm2 while grassland and woodland increased by 107,975 hm2 and 17,157 hm2, respectively. The major factors responsible for these changes are identified as the change in the government policy on preserving the environment, continued growth in mining, and urbanization. The efforts in restoring the deteriorated ecosystem have reaped certain benefits in reducing the spatial extent of sandy land through replacement by non-irrigated farmland, woodland and grassland. On the other hand, continued expansion of mining industry and urbanization has exerted adverse impacts on the land landscape. At present regional economic development conflicts directly with the protection of the natural environment. Such a conflict has caused the destruction to the land resources and fragmentation of the landscape accompanied by land desertification, the case is even serious in some localities.
Modeling Gross Primary Production by Integrating Satellite Data and Coordinated Flux Measurements in Arid and Semi-Arid China
WANG He-Song,JIA Gen-Suo,FENG Jin-Ming,ZHAO Tian-Bao,MA Zhu-Guo,
WANG He-Song
,JIA Gen-Suo,FENG Jin-Ming,ZHAO Tian-Bao,MA Zhu-Guo

大气和海洋科学快报 , 2010,
Abstract: Assessing large-scale patterns of gross primary production (GPP) in arid and semi-arid (ASA) areas is important for both scientific and practical purposes. Remote sensing-based models, which integrate satellite data with input from ground-based meteorological measurements and vegetation characteristics, improve spatially extended estimates of vegetation productivity with high accuracy. In this study, the authors simulated GPP in ASA areas by integrating moderate resolution imaging spectral radiometer (MODIS) data with eddy covariance and meteorological measurements at the flux tower sites using the Vegetation Photosynthesis Model (VPM), which is a remote sensing-based model for analyzing the spatial pattern of GPP in different land cover types. The field data were collected by coordinating observations at nine stations in 2008. The results indicate that in the region during the growing season GPP was highest in cropland sites, second highest in woodland sites, and lowest in grassland sites. VPM captured the temporal and spatial characteristics of GPP for different land covers in ASA areas. Further, Enhanced Vegetation Index (EVI) had a strong liner relationship with GPP in densely vegetated areas, while the Normalized Difference Vegetation Index (NDVI) had a strong liner relationship with GPP over less dense vegetation. This study demonstrates the potential of satellite-driven models for scaling-up GPP, which is a key component for studying the carbon cycle at regional and global scales.
Morphological Diversity of Populations of the Genus Prosopis in the Semiarid Chaco of Northern Cordoba and Southern Santiago Del Estero  [PDF]
Marisa Jacqueline Joseau, Aníbal Ramón Verga, María del Pilar Díaz, Norma Beatríz Julio
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.411261
Abstract:

The objective of this study consisted in the characterization of morphological variability presented in the Prosopis population in the corridor that unites the semiarid with the arid region in Argentina. In this region, four species of Prosopis get in contact (P. chilensis, P. flexuosa, P. alba and P. nigra). Due to the fact that these species make fertile hybrids, this corridor has an enormous diversity. The mothers allowed the differentiation of five morphologic groups, which from the point of view of classic taxonomy have been classified in 16 taxa. Only groups 3 and 4 presented intermediate characteristics. The morphologic study of the descendants showed that the regrouping of the intermediate groups had a high error rate. This fact reaffirms the condition of intermediate groups. The canonical correlation analysis between the morphologic variables of the

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