Applied Mechanics and Materials Vols. 522-524

Abstract: Evaluation of water-saving development level of irrigation management level is an important foundation to make the water-saving and irrigation policy, and improve irrigation management. This paper established a comprehensive evaluation system for the developing level of water-saving and irrigation management after comprehensively analysis of main contents of irrigation management. It include 4 secondary level indicators and 16 third-level indicators, and build a comprehensive evaluation model. Further more, entropy method and gradation analysis method were introduced to calculate the combination weight of each evaluation indices, which enhance the scientific in weight calculation, and a comprehensive evaluating model for irrigation management and water-saving developing level was established on the basis of it. The comprehensive evaluation of irrigation management and water-saving developing for Sichuan Province and 21 other regions was done by this model, and the results are accord with Sichuan Provinces actual situation of the irrigation management and water-saving developing. Therefore, the model of comprehensive evaluation for irrigation management and water-saving development level has a relative strong practicability, which can offer scientific guidance for irrigation management and water-saving development in different regions.

Abstract: To enhance the utilization efficiency of water and fertilizer resources, and improve agricultural ecological environment in resettlement area, a crop planting structure optimization model was established by the use of multiple objective linear programming (MOLP) method, and solved by two-phase algorithm. In this model, multiple targets, such as the economic, social and ecological benefits of this region were taken into account. The results showed that the MOLP model and its solution were feasible and practical. The optimized area of rice, corn and tobacco reduced by 16%, 100% and 76% respectively, and the optimized area of wheat and sugarcane increased by 82% and 78% compared with the current planting area. And the net economic and social benefits increased by 4% and 62%. The optimization scheme played a guiding role in the adjustment of agricultural structure, and promoted the sustainable development of agriculture in resettlement area.

Abstract: When energy crisis is somewhat relieved by the shale gas production, serious negative impacts are simultaneously created to the environment e.g. the regional underground water system will be seriously damaged. Currently, the shale gas production, which is blossoming in China at present, centralizes primarily in the South-west area, where the hydrological environment is quite complicated and pretty weak. In this paper, three threatens caused during the shale gas exploitation is summarized and the crisis source is also outlined. Furthermore, the probable solutions aiming at these problems are discussed, thereby the concept of ‘Water resources tolerance ability evaluation model in SouthWest China’ being proposed. This paper emphasizes that the further enhancement of environment monitoring, improvement of legislation in the related areas as well as domestic adjustment of production technologies are critical to balance the industrializing production and sustainable development.

Abstract: Interactions between civilizations and ethnic groups have generated a fusion of customs and lifestyles, with an important effect on plant genetic diversity. The loss of local species and varieties usually results in irreversible loss of the genetic diversity they contain, this has dangerously shrunk the genetic pool that is available for natural selection and art selection, and has consequently increased the vulnerability of agricultural crops to sudden changes in climate, and to the appearance of new pests. Currently, biotechnology and genomic selection have enabled the genetic alteration of crops, improved soil productivity, and enhanced weed and pest control, and benefit to the development of plant genetic diversity. For example, next generation sequencing (NGS) and bioinformatics, as the gold standard, they provide a powerful tool for discovery of domestication genes in crop plants and their wild relatives.The objectives of this article are to review the development of plant genetic diversity and summarize the research of biotechnology and genomics for plant. Then, we look forward and consider the significant of development of plant genetic diversity by biotechnology and genomics.

Abstract: The cassava green mite (Mononychellus mcgregori) was listed as a quarantine pest in the world. The risk of invasion of M. mcgregori was on the increasing with the development of foreign trade, especially in Guangxi province, China. Therefore the prediction of geographic distribution areas and pest risk analysis should be done urgently. In this paper potential geographic distribution areas of M. mcgregori in Guangxi were predicted with niche model MaxEnt. Through validating prediction result and analyzing technical parameter AUC-value, it is sure that niche model MaxEnt is suitable for predicting potential distribution areas of M. mcgregori in Guangxi. At the same time the useful method would be utilized to predict potential geographic distribution areas of other cassava pests.

Abstract: Response of gas exchange to VPD in leaves of four trees (Prunus serrulata, Prunus lannesiana, Populus deltoides I-69 (I-69) and Populus × euramericana Neva (I-107)) at the campus of Shandong University in Jinan, Shandong Province were measured. The result showed that: the stomatal conductance increased with increasing VPD, and g_s reached g_s-max at intermediate VPD, and a steady decline in g_s with further increases in VPD. This response pattern was fitted by a parabolic curve (g_s=aD²+bD+c, D=VPD, R²>0.52). The g_s-max at intermediate VPD with changing VPD showed that there was an optimal VPD (or RH) to plants. Therefore, while VPD (or RH) was higher or lower than the optimal VPD (or RH) of plant, g_s would decrease. The response of g_s to VPD in I-69 and I-107 were much more sensitive than P. serrulata and P. lannesiana.

Abstract: Climate change will result in the distribution range of plants that have changed and the impact on wildlife habitat quality. We will explore the Baima Snow Mountain Nature Protection Area Abies georgei population structure change and climate change impact on the growth of Abies georgei population, which can offer theoretical basis for biodiversity protection. Understanding the ecological characteristics is necessary to analyse its population structure and probe into the causes. We set up 27 sample plots for field study above 3300m of Baima Snow Mountain in the northwest of Yunnan Province. We mapped age class distribution and number of survival individuals at different altitudes for analyzing the population age, structure and quantitative characteristics. Abies georgei has a stable development on mid-altitude. The population at mid-altitude showed a growing trend with a large proportion of saplings and number of individuals decreased with increase of age. The age structure and densities of low altitude shows a distinct increase in the number of survival individuals. Compared with other altitudes, Abies georgei population of each age classes is reasonable, except declining of age class I. The abnormal growth of juveniles at low and high altitudes, which may be caused by climate changes, becomes the disadvantage of Abies georgei population in the future.

Abstract: This paper explores the behavior model of urban forest recreationists and provides an analysis on the relationships between the constructs of destination image, recreation benefits, perceived value and behavioral intentions. Statistic materials suggest that the four principal components of destination image construct are accessibility, attractiveness, brand and amenities, while the major factors of recreation benefits include functional, social and emotional benefits. Structural equation modeling (SEM) technique being applied, the results indicate that destination image has both direct and indirect effects on the behavioral intentions, and the recreation benefits influences the behavioral intentions through perceived value as a moderating variable. In addition, the relationship path of destination image recreation benefits perceived value behavioral intentions has been proved evident in this study.

Abstract: Growth characteristics of nutritional and reproductive tiller of Poa viridula L. were studied with no quadrate sampling method. The results showed that the number of leaves and biomass of nutritional tiller were more than reproductive plants, but the height was less than reproductive plants. The biomass and plant height of nutritional or reproductive tiller was in line with the exponential function relationship, leaf biomass and plant biomass accorded with the linear relationship. The growth of reproductive organs spike, spike length and biomass of reproductive plants conformed to the power function relationship, and had reached a very significant level.

Abstract: Characteristics of seed-setting of two Leymus chinensis ecotypes under saline-alkali soil and sandy soil habitats on Songnen plain were studied, such as number of grains and seed-setting percentage. The results showed that number of grains and seed-setting percentage of two L. chinensis ecotypes fluctuated within a certain range. Variation coefficients of single spike grain number and seed-setting percentage were 79.37% and 87.2% higher. The number of grains and seed-setting percentage of two L. chinensis ecotypes under saline-alkali soil habitat were lower than those under sandy soil habitat. Significance test showed that seed-setting percentage of two L. chinensis ecotypes, and the single spike grain number of grey-green L. chinensis ecotypes between saline-alkali soil habitat and sandy soil habitat were significant or very significant. In results, the sexual reproduction of two L. chinensis ecotype populations had a stronger adaptation for the habitats, the two ecotypes take the same adaptable reproduction strategy, due to the change of habitat condition, the characteristics of seed-setting have a plastic changes accordingly, and individual difference in population under the same habitat was resulted by microhabitat differences.