Advanced Materials Research Vols. 1010-1012

Abstract: With the speeding up of the social transformation and the deepening of market economy, soil and water loss problem is increasingly appearing, and so it has becoming the core issue of ecological environment construction. This article attempts to field research as a logical starting point, combined with related literature, in order to Enshi G County as a case, not only discusses the basic situation of soil and water loss and its harm to ecological environment but also analyses its multi-dimensional causes. In the meantime, this paper argues that the effective governance of the soil and water loss lies in government-led social governance model, and also initial shows its policy implications.

Abstract: Morphological development of rill at hillslope formed a microrelief dynamic response system with soil erosion driven by rainfall. To reveal the formation mechanism of this system, scientifically quantification is the key problem. In recent years, domestic and foreign scholars had achieved fruitful results in rill evolution and quantized fields. This paper analysised the existing problems in the present research based on summarizing the current existing methods of rill morphology quantitation, and put forward the research direction in the future.

Abstract: Sediment deposition caused by debris flows is an important process controlling the evolution and regression of lake, and even a pervasive environmental problem. The frequent debris flows construct a vital links between mountain slope and Qiong Lake transporting lots of sediment into lake, and further making the lake depth and lake area shallower and smaller constantly. In the paper, we select the Guanba River in the northeast of Qiong Lake as a case studying the effect of debris flows on Lake depositon and the characteristics of typical debris flow, and document the sediment deposition in the Guanba River estuary. The control factors contributing to debris flow initiation indicate that the debris flows are drove by rainfall, earthquake and human activities together, and the occurrence frequency of debris flows in the study area will continue to increase.

Abstract: Analysising twenty-one silt dams in Jiuyuangou watershed and thirty-six silt dams in Tuwei River Watershed drilling hole sampling’s data, Jiuyuan gou Watershed’s silt dams in coarse sand size mainly concentrated in the 0.05mm,Tuwei River Watershed’s silt dams in coarse sand size mainly concentrated in the 0.05mm~0.10mm,The dam upstream sand size is generally larger than the dam downstream, sorting depends on sediment dam on the dam upstream tosand size, dam upstream sediment grain size is coarse separation effect is better, warping dam and reduction effect is more obvious.

Abstract: Reduction effects of grass on runoff and sediment yield and its mechanical mechanism of grass was studied under rainfall intensities of 45, 87 and 127mm/h with 20°slope gradient using simulated rainfall experiment. the results showed that average runoff rates ranged from 39.7 to 126.0 L/min for bare plots and 0.34 to 6.22 L/min for grass plots, and the runoff rates from grass plots were much less than from bare plots. Average sediment yields varied from 3636.7 to 9436.3 g/min for bare plots and from 26.7 to 581.5 g/min for grass plots. The critical flow shear stress of 2.85 N/m² on grass slope and 0.861 N/m² on bare slope were got under experiment condition. The sediment yield increased with the increase of flow shear stress. The experiment results are meaningful for quantifying runoff and sediment reduction and deepening soil erosion mechanical process also.

Abstract: Sediment transport capacity of slope runoff is an important hydrodynamic parameter in the establishment of soil erosion prediction model. According to simulated runoff-scouring experiments, sediment transport capacity of slope runoff under different conditions is calculated. The impact factors of sediment transport capacity of slope runoff were analyzed by the method of Mean Impact Value, and then the input variables including dry bulk density, slope, Inlet flow, outlet flow, hydraulic radius, flow rate were determined. GRNN model was established and optimized by Adaboost algorithm to forecast Sediment transport capacity of slope runoff. The validation results showed that the GRNN model was applied to Sediment transport capacity forecasting of slope runoff. In conditions of experimental training samples, GRNN model had better computed results compared to BP Neural network model, and Adaboost algorithm could effectively decrease error of GRNN model.

Abstract: The blacklands in northeast China is an important food producing area and marketable grain base, it plays an important part in the development of national food security. Serious losing of soil and water has become a bottle neck in the development of national economy for recent years. In order to understand the research trend on soil and water loss of Black Soils in Northeast China and to find its problems and shortcomings, the authors mainly analyzed the Present Situation and characteristics, the hazards, the causes, research methods and control measures of soil and water loss in blackland.

Abstract: Rhizoctonia solani Kühn is a causal pathogen responsible for many types of plant disease worldwide and a major soilborne fungal pathogen that severely impairs yield and quality of tobacco worldwide. Activities, pathogenicity of the cell wall-degrading enzymes produced by the Rhizoctonia solani from tobacco target spot disease both in liquid medium and in tobacco tissue were studied. The result showed that R. solani from tobacco can produce pectinase and cellulase both in vitro and vivo, and the activity of PG and PMG was the highest in vitro. The activity of Cx and β-glucosidase was the highest in vivo, and enzyme production ability of strong pathogenicity strains is stronger than the weak pathogenicity strains in vitro.

Abstract: we examined the photosynthetic responses of submerged marestail in three lakes using pulse amplitude modulated (PAM) fluorometry. Three lakes were studied across a gradient of water temperature, with low water temperature conditions in Grass Lake and Arrow Bamboo Lake, and higher water temperature in Five Colored Lake. In the field, electron transport rates (ETR_max) were measured as rapid light curves (RLCs) by in situ yield measurements. Submerged marestail showed higher photosynthetic activity in Five Colored Lake compared to the other lakes, a response consistent with the adaptation of marestail in Five Colored Lake to high water temperature. The optimal temperature for photosynthesis of submerged marestail in Jiuzhaigou is about 12 °C. These results indicate that in different lakes the function of these aquatic plants is associated with a diversity of place-dependent environmental conditions, especially water temperature that leads to pronounced differences in the plant’s ecophysiological reactions.

Abstract: Nutrition components of bamboo shoots sampled from 6 large-sized and shoots-based bamboo species in Yunnan were analyzed in this paper. The results showed that bamboo shoots were naturally green food with merits of high protein, fiber, ash content, low sugar and low fat, however with defects of sulfur-containing amino acid and calcium deficiency, consisting of essential amino acid such as aspartic acid, phenylalanine, tryptophan and lysine, also including other important microelements as iron, zinc and manganese, and vitamin E.