Search

The conventional evaluation methods for the state of agricultural environmental geological system mainly use the support vector regression (SVR) model to process the evaluation samples, which is vulnerable to the influence of the sensitive loss function, resulting in the high difference of the evaluation entropy. Therefore, a new evaluation method for the state of agricultural environmental geological system needs to be designed based on the optimized particle swarm optimization algorithm. That is to say, combining with the evolution process of regional agricultural environmental geology, the accurate state evaluation target is selected, the state evaluation system of agricultural environmental geology system is constructed, and the state evaluation model of agricultural environmental geology system is designed combined with the optimized particle swarm optimization algorithm, so as to complete the state evaluation of geological system. The results demonstrated the suggested methodology assesses the state of an agricultural environmental geological system. Key factors included soil texture (0.254), soil nutrient (0.118), and soil pH (0.256). It showed that the designed evaluation method of agricultural environmental geological system state based on optimized particle swarm optimization algorithm has good evaluation effect, reliability and certain application value, and has made certain contributions to the formulation of reasonable agricultural ecological protection scheme. [ABSTRACT FROM AUTHOR]

[Objective] Species composition and flora of vascular plants in the middle and upper reaches of the Yarlung Zangbo River were analyzed, to provide scientific basis for the estimation and protection of plant diversity, construction of ecological security shelter for the Tibetan Plateau. [Methods] In the middle and upper reaches of the Yarlung Zangbo River, quadrat (line transect) method was applied to investigate the phytocoenoses in sample plots, and relative literature was used to analyze the floristic composition and floristic element of vascular plants in the middle and upper reaches of the Yarlung Zangbo River. [Results] 1 There are 96 species (including subspecies and variations), 69 genera of 35 vascular plant families, accounting for 16.83%, 5.48%,1.66% and 11.63%, 2.02%, 0.31% of total vascular plant families, genera and species in Tibet and China. (2) There are 24 monotypic-genus families, accounting for 68.57% of the total family number in the local area; 22 monotypic-species families, accounting for 62.86% of the total family number in the local area. Local flora shows the characteristics of ancient relict, such as Euphorbiaceae, Rubiaceae, Liliaceae and Ranunculaceae, they are all ancient primitive groups of the third flora and the fourth flora. (3) Local vascular plant genera M into 10 areal types and 8 variations. 4 Temperate elements are much more than tropical elements, R/T is 0.19, indicating that vascular plants have typical temperate nature and residual tropical nature. There are only a few endemic genera, but more endemic species to the local area, and these species are closely related, of which there are some transitional species, indicating that local flora is too young to experience more differentiation and specialization. 5 There are 24 Chinese endemic species, accounting for 25% of total number of species in the local area; among which there are 12 endemic species to Tibet, accounting for 50% of endemic species to China, 12.5% of total number of species in the local area. Four key wild plant species are included in the second batch of national key protection. [Conclusions] 1 There are scarce plant groups in the local area. 2 Among the obvious advantages, single-genus (species) families possess the absolute advantage, and the flora has ancient origins. (3) The local flora has diversified distribution types, and the complicated geographical elements. 4 Temperate species possess obvious advantages, and the flora is young. 5 Rich unique and rare species have high species diversity protection and research value. [ABSTRACT FROM AUTHOR]

The research aimed to analyze changes in photosynthetic characteristics of Paeonia ludlowii under saline-alkali stress, and annual seedlings of P. ludlowii were taken as the materials. Photoresponse process of P. ludlowii leaves under saline-alkali stress was simulated, and different models were used to fit photoresponse curve. The results showed that Pn of P. ludlowii leaves showed the trend of first rising and then declining with PAR increased under saline-alkali stress; both Gs and Tr showed a rising trend with PAR increased; Ci showed the trend of first declining and then rising with PAR increased. Photoresponse curve fitted by modified rectangular hyperbolic model had the best effect, and it was the optimal fitting model. P. ludlowii could adapt to saline-alkali stress in lower concentration, showing that P. ludlowii could be introduced and cultivated in saline-alkali land at a lower level. [ABSTRACT FROM AUTHOR]

With seeds of Caragana versicolor in Purang County, Tibet as the materials, the seed germination and seedling growth of C. versicolor were measured under acid and alkali stress, and the soil acidity and alkalinity for normal growth and development of C. versicolor were determined,so as to provide the theoretical basis for cultivation of C. versicolor in acidified or alkaline soil. The results showed that the seed germination of C. versicolor was promoted when treated by strong acid(pH 3) and strong alkali(pH 11) solutions, and the seedling effect was good. The results also indicated that C. versicolor was a kind of plant with strong acid and alkali resistance, suitable for cultivation in acid and alkali soil areas. [ABSTRACT FROM AUTHOR]

Understanding population structure provides basic ecological data related to species and ecosystems. Our objective was to understand the mechanisms involved in the maintenance of Quercus aquifolioides populations. Using a 1 ha permanent sample plot data for Q. aquifolioides on Sejila Mountain, Tibet Autonomous Region (Tibet), China, we analyzed the population structure of Q. aquifolioides by combining data for diameter class, static life table and survival curve. Simultaneously, the spatial distribution of Q. aquifolioides was studied using Ripley’s L Function in point pattern analysis. The results showed: (1) Individuals in Q. aquifolioides populations were mainly aggregated in the youngest age classes, that accounted for 94.3% of the individuals; the older age classes had much smaller populations. Although the youngest age classes (Classes I and II) had fewer individuals than Class III, the total number of individuals in classes I and II was also greater than in classes IV to IX. In terms of tree height, few saplings, more medium-sized saplings and few large-sized trees were found. The diameter class structure of Q. aquifolioides populations formed an atypical ‘pyramid’ type; the population was expanding, but growth was limited, tending toward a stable population. (2) Mortality of Q. aquifolioides increased continuously with age; life expectancy decreased over time, and the survivorship curve was close to a Deevey I curve. (3) The spatial distribution pattern of Q. aquifolioides varied widely across different developmental stages. Saplings and medium-sized tree showed aggregated distributions at the scales of 0–33 m and 0–29 m, respectively. The aggregation intensities of saplings and medium-sized trees at small scales were significantly stronger than that of large-sized trees. However, large-sized trees showed a random distribution at most scales. (4) No correlation was observed among saplings, medium- and large-sized trees at small scales, while a significant and negative association was observed as the scale increased. Strong competition was found among saplings, medium- and large-sized trees, while no significant association was observed between medium- and large-sized trees at all scales. Biotic interactions and local ecological characteristics influenced the spatial distribution pattern of Q. aquifolioides populations most strongly. [ABSTRACT FROM AUTHOR]

To figure out current landscaping of Linzhi City, analyze the basic situation of local landscaping quantitatively, and solve related problems in landscaping, this paper applied the "five-point sampling method" for the layered survey of landscape plant communities, investigated landscape plant species and their application in different regions of Tibet, particularly current landscaping, features and problems of Linzhi City, and put forward corresponding measures. The investigation covered 321 species (cultivars) of 196 genera, 87 families. The results showed that (1) Salix alga, Ligustrum x vicaryi, Poa pratensis had the highest importance value in the tree layer, shrub layer and herb layer, respectively, and the Importance value was 68.620, 24.139 and 35.747, respectively (2) Among all landscape plants in Linzhi City, the most applied families were Rosaceae (48), Salicaceae (21), Asteraceae (20), Leguminosae (20), Gramineae (19), Pinaceae (16), Cupressaceae (13) and Oleaceae (12), accounting for 14.95%, 6.54%, 6.23%, 6.23%, 5.92%, 4.98%, 4.05% and 3.73% of the total investigated species. (3) Natural environment of the plateau was the most influential restraint for local landscaping, and the application of landscape plants varied greatly among regions. (4) The local area was endowed with rich landscape plant resources, but these resources were not fully developed. [ABSTRACT FROM AUTHOR]

To figure out current urban greening of Lhasa City, analyze the basic situation of its landscaping quantitatively, and solve problems in urban greening, this paper applied "five-point sampling method" for the layered survey of landscape plant communities, investigated landscape plant species and application in Tibet comprehensively, elaborated current landscaping, characteristics and problems of Lhasa City, and gave pertinent countermeasures. The investigation covered 159 landscape plant species (varieties), 100 genera and 45 families. The results showed that species with the highest importance value in tree layer, shrub layer and herb layer were Prunus cerasifera f. atropurpurea (49.861), Platycladus orientalis cv Sieboldii (27.756), Poa pratensis (55.386); in the tree and shrub layer, Rosaceae was most applied (27 species), Salicaceae was the second most applied (18 species), followed by Oleaceae (9 species), Cupressaceae (8 species) and Leguminosae (6 species), the 5 families accounted for 24.77%, 16.51%, 8.26%, 7.34% and 5.50% of the investigated trees and shrubs; the applied landscape species were not rich, and landscaping development was not even; landscape plants were not reasonably combined, the introduced species accounted for a high ratio, and the ratio of native species was extremely low. [ABSTRACT FROM AUTHOR]

Site survey was applied to investigate landscape plants in Shigatse City of Tibet, current situation, pattern and problems of landscaping in the city were analyzed, and corresponding moves were proposed. The investigation covered 71 species (including varieties) of 45 genera and 20 families. The results showed that Populus × beijingensis W. Y. Hsu, Platycladus orientals and Poa pratensis had the highest importance value (47.787,86.802,75.700) in the tree layer, shrub layer and herb layer, respectively. Among all landscape plants in the city, Salicaceae is the most applied one, including 15 species; Rosaceae is the second most, including 10 species; and Leguminosae is the third, including 6 species. The three families account for 21.13%, 14.08% and 8.45% of the total investigated plants. The simple compound structures such as "tree + ground cover" and "shrub + ground cover" are major greening patterns of the city. Growth vigor of local plants is poor, and "ensuring the survival rate" is a key task in the urban landscaping. [ABSTRACT FROM AUTHOR]

Garden nurseries in Linzhi City, Tibet were comprehensively investigated, 132 garden plant species were covered The investigation showed that garden nurseries in the local area remained in the initial development stage, and the scale of most nurseries was small, and there was blank in many aspects of the landscape architecture industry. Most seedlings were introduced from the interior regions of China, self-bred seedlings in local nurseries accounted for only 32.68%. On the basis of the investigation results, garden nurseries in Linzhi City were analyzed specifically to figure out advantages and deficiencies of local garden nurseries. [ABSTRACT FROM AUTHOR]

Through investigating Tibetan courtyard landscapes in Linzhi City, Tibet, it was found that Tibetan courtyards attached more importance to flower plants and garden crops, focused on natural style and easy maintenance, but not pruning; Tibetan courtyard landscaping valued shape, color, flower season and visual aesthetics of flowers, tried to build "gardens" with flower configuration as the major content, similar aesthetic concepts and landscaping style with European gardens; moreover, it paid more attention to plants, but not waterscape design; in Tibetan gardens, lawns occupied a secondary position next to flowering plants, fruit trees and garden crops. [ABSTRACT FROM AUTHOR]

To figure out current landscaping of Tibet, analyze local garden landscaping quantitatively, and solve greening problems, this paper adopted "five-point sampling method" for the stratified survey of garden plant communities, investigated species and application of garden plants in Tibet comprehensively, discussed current situation, characteristics and problems of local landscaping, and proposed corresponding measures. According to the investigation, (1) There arc 368 applied garden plant species (including varieties) of 207 genera, 91 families; (2) In the tree layer, shrub layer and herb layer, Picea likiangensis var. likiangensis, Buxus megistophylla, Poa pratensis have the highest importance value, i.e., 43.050, 25.128, 45.950; (3) The most applied families in local landscaping are Rosaceae (53), Salicaceae (23), Compositae (21), Leguminosae (20), Gramineae (19), Pinaceae (16), Oleaceae (14) and Cupressaceae (12), accounting for 14.40%, 6.25%, 5.71%, 5.43%, 5.16%, 4.35%, 3.80% and 3.26% of the total, respectively; (4) The total landscaping level is poor and uneven, application of landscaping plants varies greatly among regions, garden application is poor; (5) Proportion of garden landscapes is unreasonable. [ABSTRACT FROM AUTHOR]

Firstly, the connotations and influencing factors of ecosystem health are discussed, and then the assessment principle, evaluation standard and evaluation method of ecosystem health and the establishment and measurement of ecosystem health indicators are studied. Through the study of its connotation and evaluation, feasible measures to effectively promote the development of ecosystem health are put forward finally. [ABSTRACT FROM AUTHOR]

In recent decades, with the constant progress of society, the study of ecological civilization has attracted extensive attention of scholars at home and abroad, and more in-depth research on its theory and application has been conducted. In this paper, the historical background, theoretical and realistic bases of ecological civilization were analyzed, showing that the birth and development of ecological civilization is inseparable from the historical development of human society. Then the development prospects and application fields of ecological civilization were discussed further. [ABSTRACT FROM AUTHOR]

Based on the introduction of concept of forest lifter, changes in the amount of forest lifter with climate zone, elevation, forest type and age of stand were analyzed, and then the decomposition of forest lifter was discussed. [ABSTRACT FROM AUTHOR]

With the continuous development of human society and economy and the continuous progress of industrial technology, more and more pollutants are discharged into the natural environment, and soil environment is also affected at the same time. Among pollutants leading to soil pollution, heavy metals have resulted in most serious soil pollution. Here, many control and restoration approaches to soil pollution from heavy metals are proposed, and characteristics and applicable conditions of various methods are compared, so as to provide theoretical references tor the control and restoration of soil pollution from heavy metals in future. [ABSTRACT FROM AUTHOR]

Mila Mount in Southeast Tibet is the west boundary of the horizontal distribution of Betula platyphylla. It is also the highest altitude area in China and the world, where Betula platyphylla is distributed. Based on the investigation of regional sample plots and the analysis of analytic trees, this paper compared the biomass and yield of Betula platyphylla population at different slope orientation and different altitude. The results showed that the growth of Betula platyphylla was greatly interfered by human activities. The yearly productivity of Betula platyphylla grown in Mila Mount was 363.1-2,072.94 kg x hm(-2), and the biomass was 7,625.00-33,167.00 kg x hm(-2), indicating that the biomass of Betula platyphylla was quite different for different population. The productivity and biomass of Betula platyphylla coppice after cutting were lower than those of seedling forest, and there existed youth broken-down in the coppice. The zonal changes of water resources had no significant effect on the water allocation and the biomass of Betula platyphylla.