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Zhangye, China

Li X.,Shaanxi Normal University | Li X.,Shangluo College | Huang C.,Shaanxi Normal University
Journal of Natural Disasters | Year: 2014

Slackwater deposits (SWD) of 2012 flood were investigated and sampled in the main stream and tributaries of middle reaches of the Yellow River. Grain-size distribution and magnetic susceptibility were comparatively analyzed for the samples collected in different deposited places. The results show that magnetic susceptibility of the 2012 flood SWD at middle reaches of the Yellow River are (31.2-51.3) × 10-8m3/kg, very close to that of the Malan Loess at the middle reaches of the Yellow River. This means that they are newly deposited and are not influenced by the weathering and pedogenesis. The grain size of the 2012 flood SWD in the middle reaches of the Yellow River and tributaries is dominated by silt, and with a certain proportion of sand and clay. This indicates that they are deposited from the suspended sediment load of the floodwater at a high-stage stagnant environment. Compared with that in the Wuding River, Yanhe River and Beiluo River, The SWD in the main stream of the Yellow River contains more clay-sized particles. With the increase of transport distance, the particle size of the suspended sediment in middle reaches of the Yellow River would change gradually into thinner one. The results of this study give a reference to prevention and control of flood and soil erosion in the main stream and tributaries of the middle reaches of the Yellow River. Source

Li F.-H.,Shangluo College
Research Journal of Applied Sciences, Engineering and Technology | Year: 2013

In this study, improved principal component analysis method is put forward to avoid the shortage of comprehensive evaluation dealt with principal component analysis method. When the contribution rate of the first principal components is short of asks, we can choose to rotate factor loading matrix and select multiple main components and synthesize and weigh the variation coefficient and variance contribution as weight coefficient, to set up a comprehensive evaluation model. As an example of the main indicators of Shangluo city Industrial data, the comparative study uses factor analysis and improved model, systematic classification with cluster analysis. The result shows that comprehensive evaluation of the improved model in the practical problems is more reasonable and objective. © Maxwell Scientific Organization, 2013. Source

Peng X.,Shangluo College | Zhang S.,Northwest University, China
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2012

Agroforestry is the most effective way to restore the disturbed lands in the hilly region of Shangluo and to develop the currently poor local economy. In order to study the potential benefits of tree-based intercropping systems, photosynthesis, growth and yield of soybean (Qindou 8) (Glycine max L.) and salvia (Radin salviae Miltiorrhizae) were studied by measuring photosynthetic active radiation (PAR), plant water deficit and soil moisture in a 6-year-old plantation of walnut (Juglans regia L.) grown at a spacing of 5 m × 3 m in the hilly region in Shangluo. The effects of tree competition significantly reduced the PAR, the net photosynthetic rate (Pn), growth and yield of individual soybean or salvia plants growing near (within 1m near) tree rows. In 2010, daily plant water deficits were not significantly correlated with the Pn and growth and yield of the both crops. However, the soil moisture (15 30cm depth) was significantly correlated with biomass and yield of the crops. The PAR was highly correlated with growth and yield of the both crops, which indicated that competition for light is one of the key factors impacting crop yield. Possible remediation strategies were suggested that may reduce competitive interactions between the tree and crop species. Source

Yan H.,Northwest University, China | Peng X.-B.,Shangluo College | Xue J.-J.,Chungnam National University
Chinese Journal of Applied Ecology | Year: 2012

This paper studied the variations of leaf photosynthesis gas exchange, chlorophyll fluorescence, and free amino acid contents of Heyedysarum scoparium under the stress of different concentration NaCl, aimed to understand the effects of salt stress on the leaf physiological characteristics and free amino acid metabolism of the plant. Under mild salt stress, the photo-damage of the leaf photosystem II was avoided via the dissipation of excess excitation energy, and stomatal limitation was the main factor reducing the photosynthesis rate. With the increase of salt stress, the leaf photo-protection was not sufficient to avoid oxidative damage, and thus, the damage to photosystem II happened. Under the stress of 200 mmol NaCl·L-1, non-stomatal limitation was the main factor responsible for the inhibition of photosynthesis. The accumulation and metabolism of major free amino acids in H. scoparium leaves varied under salt stress. Under mild salt stress, the major free amino acids such as proline, glutamate, aspartate, and alanine had a significant accumulation, but with the further increase of salt stress, the aspartate and alanine contents in H. scoparium leaves decreased, while the synthesis and accumulation of praline increased. Source

Peng X.,Shangluo College | Zhang S.,Northwest Agriculture and Forestry University
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2013

Agroforestry systems promote ecological, social and economic benefits in comparison with traditional forestry systems. Agroforestry systems provide various products for household including but not limited to, food and medicinal products for humans and animals, timber for construction, fuelwood for domestic use and income for the household. They also contribute to environmental sustainability and can act as a buffer to climate extremes. In order to study the physioecological characteristics of soybeans and salvia grown in agroforestry systems, the photosynthetic characteristics and parameters of chlorophyll fluorescence were examined. The study sites were located in Shanghe village (latitude 33°50'19″N, longitude 109°53'38″E, elevation 451m a.s.l.), Shangluo, Shaanxi Province. The total extent of the study site is 8 hectares. In this study, soybeans (Glycine max L. Merr.) Qindou 8, and medical plant salvia (Radin salviae Miltiorrhizae) were selected as agricultural crops. Within the study site, best areas were selected to implement the two treatment combinations, walnut-soybeans and walnut-salvia, replicated 3 times. In addition, areas without walnut trees were also selected for control measurements. The walnut trees were planted in 2004 at a within row spacing of 3m and between row spacing of 5m. The tree rows were oriented north-south. Twelve sample locations around each tree were assigned in the following manner: 1) perpendicular to the tree trunk at 1m and 2.5 m east and west (4 locations), 2) and at the same distances (1m and 2.5m east and west) from the tree row at 1 m north (4 locations) and 1 m south (4 locations) of the tree trunk. At each time of sampling, a single leaf from the upper crop canopy was selected at the above indicated locations. The results indicated that photosynthetic active radiation (PAR) was reduced significantly from full daylight at 1m from the walnut tree rows. The diurnal variations of photosynthetic rate (Pn), stomata conductance (Gs) and transpiration rate (Tr) of soybean were also lower close to the tree rows. The diurnal variations of photosynthetic rate in salvia at different distances from the tree row were different, and there was a "lunch break" phenomenon observed. The photosynthetic parameters for both crops were lower in the agroforestry system compared to the rates measured in the control treatment. The total chlorophyll and apparent quantum yield (F{cyrillic}) for both crops increased, whereas the light compensation point (LCP) and light saturation point (LSP) decreased with increasing degree of shade. Meanwhile, the Fv/Fm, F{cyrillic}PSII and qP were significantly higher than those quantified in the control treatment for both crops, But, qNP decreased with increasing degree of shade, indicating that soybean and salvia have strong adaptability to low irradiance. The research area is located in the ShangLuo Mountain area, and the regional economic development is very slow, and land natural resources is also in short supply. Therefore, based on the results from this study, it appears that agroforestry systems can potentially restore these disturbed lands and contribute to the development of the economy in the hilly region in Shangluo. Source

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