Biomedical subjects

Zhiping Fan

Publications and source records attributed to Zhiping Fan.

12 recordsLinked to original sources

PubMed2006

[Rhizosphere effects of Pinus sylvestris var. mongolica on soil phosphorus transformation].

To understand the phosphorus (P) mobilization mechanism of Mongolian pine (Pinus sylvestris var. mongolica) on a P-deficient semi-arid sandy soil of northern China, this paper compared the P fractions and acid phosphomonoesterase (AP) activity in the bulk and rhizosphere soils under different age Mongolian pine plantations. The results showed that when compared with the bulk soil, the organic C, labile organic P, and organic C/P ratio increased significantly, microbial and AP activities improved, and organic P mineralization accelerated in the rhizosphere soil. Root activity of the Mongolian pine significantly increased the bioavailability of soil P, and accelerated the shift of organic P and Ca-P to Fe-P and Al-P. The rhizosphere effects on soil P in different forms enhanced with stand age, whereas in adverse on AP activity. The bulk and rhizosphere soil had the similar trend in the dynamics of its P fractions with stand age. Soil total P pool reduced gradually while labile P pool increased with stand age. It should be essential to protect forest floor to replenish soil P pool and guarantee a long-term soil P supply.

Ecosystem↗

PubMed2004

[Influence of shelterbelts structure on snow distribution pattern in shelternets in Northeast China].

The amount of snow that falls in farmland during winter in Northeast China is the important source of soil water in farmland, so the influence of shelterbelt structure on snow distribution pattern is the key problem in order to adjust structure of shelterbelts according to porosity in management practice. Based on snow depths in shelternets composed of shelterbelts with three levels of porosity, which were shelternet No. 1, shelternet No. 2, and shelternet No. 3, the snow distribution patterns in farmland were studied. The results showed that the structure of shelternet had great influence on snow distribution in farmland. With different levels of porosities, spatial pattern of snow distribution were obviously different in three shelternets. The more variant in porosity, the more obvious difference in snow distribution pattern, and the best uniformity of snow distribution appeared in shelternet with porosity of phi 2w = 0.579, phi 2s = 0.268, in which snow depth in farmland was relative even and the variability of snow depth was the least. Consequently, the relationship of porosity of shelterbelt with snow distribution pattern could be used to guide structure adjustment and optimization management of shelterbelts.

Agriculture↗

PubMed2004

[Introduction of upland rice cultivars to eastern Keerqin sandy land and their biological characteristics].

Developing water-saving rice cultivation is one important strategy for food security in China. This paper reported the experimental results of introducing six upland rice cultivars to eastern Keerqin sandy land. The field experiment results showed that under the condition of 60% water-saving, the yield of cultivars XH 95-13 and XH 95-13-6 was 10.2% and 5.5% higher than the control, respectively, while other four cultivars decreased by 6.7%-18.6%. Economically, all the cultivars except JP 121 had a higher income than the control, and the profitability of cultivars XH 95-13 and XH 95-13-6 reached 24.0% and 19.3%, respectively. The water productivity of all the six cultivars was over 0.566 kg x m(-3), increased by 59.89%-116.38%. Pot experiment showed that 12.1%-16.3% of soil moisture in 0-15 cm layer was beneficial to the growth of upland rice. In eastern Keerqin sandy land, effective tillers occurred before July 18. In brief, upland rice production could be extensively applicable in eastern Keerqin sandy land to gradually alternate the traditional lowland rice cultivation with continuous flooding, and save much underground water.

Adaptation, Physiological↗

PubMed2003

[Optimization of spatial arrangements and patterns for shelterbelts or windbreaks].

Spatial arrangements and patterns of shelterbelts or windbreaks are the key factors influencing the shelterbelt structures, shelter benefits, and shelterbelt sustainability. In order to keep the shelter benefits and achieve the sustainability of shelterbelts, it is necessary to keep the reasonable arrangements and patterns in spatiality and the continuation in time. Based on the investigations on the shelterbelts, which were established in 1992 as the models in Shuangjingzi Township, Changtu County, Liaoning Province, and combined with the experiences and practices of shelterbelt management, the authors studied and summarized the arrangements and patterns of shelterbelts, which included the direction of a single shelterbelt and shelterbelt-networks, the arrangement of tree composition in a shelterbelt, and the mixture of tree species for shelterbelts. Additionally, the spacing intervals between shelterbelt and the spatial patterns for regional shelterbelts were also discussed. The results indicated that the direction of both single shelterbelt and shelterbelt-networks should be perpendicular to the disaster winds. It is better for the structure of a shelterbelt to arrange the trees in triangle form in a shelterbelt. According to the edge effect, the tree species which grow slowly should be arranged in the edge lines, but the tree species which grow fast should be arranged in the inner lines of the mixed shelterbelts. Optimal spacing intervals between windbreaks could be predicted from the indices of a given windbreak structure (porosity), percentage of desired wind speed reduction, and tree growth model (model for determining initial protective maturity age). The patterns of shelterbelts in large scale should be evaluated and arranged according to the principles of landscape ecology. The results mentioned above would provide the evidences for shelterbelt sustainable management.

Conservation of Natural Resources↗

PubMed2003

[Advances in studies on the structure of farmland shelterbelt ecosystem].

The ecological function of farmland shelterbelt system is determined by its structure. The spatio-temporal structure is a key aspect in related researches, which is very necessary to study the integrity, stability and durability of shelterbelt modules. In this article, the researches on the structure of farmland shelterbelt ecosystem were reviewed from the four scales of tree structure, shelterbelt structure, shelterbelts network and landscape structure. The principles, methods and productions of each scale were summarized, and the prospects were also discussed. Dynamic simulation of tree growth process in shelterbelts could be conducted by the theory of form and quality structure of tree and by fractal graphics, which were helpful to study the mechanism of individual trees and belts based on photosynthetic and transpiration mechanism of individual trees. The mechanism model of shelterbelt porosity should be conducted, so that, the sustainable yield model of shelterbelt management could be established, and the optimized model of shelterbelt networks with multi-special and multi-hierarchical structure could also be formed. Evaluating the reasonability, stability and durability of shelterbelt landscape based on the theories and methods of landscape ecology was an important task in the future studies.

Agriculture↗

PubMed2003

[A research review on "fertile islands" of soils under shrub canopy in arid and semi-arid regions].

Due to the inclemency of climate and soil conditions and the intense disturbance of human beings, the soil resources heterogeneity in arid and semi-arid grassland ecosystems worldwide was gradually increased during the last century. The interaction between soil heterogeneity and shrubs induced the autogenic development of "fertile islands" and the increasing spread of shrubs in the grassland ecosystems. The development of "fertile islands" around individual shrubs could change the vegetation composition and structure, as well as the distribution patterns of soil resources, and thus, reinforced the changes of the ecosystem function and structure from a relative stable grassland ecosystem to a quasi-stable shrubland ecosystem. The study of "fertile islands" phenomenon would help us to understand the causes, consequences and processes of desertification in arid and semi-arid areas. In this paper, the causes of "fertile islands", its study methods and significance and its relationship with shrub spreading as well as the responses of vegetation to it were summarized. The problems which might occur in the study of this phenomenon were also pointed out. Our aim was to offer some references to the study of land desertification processes and vegetation restoration in the arid and semi-arid regions.

Desert Climate↗

PubMed2002

[Natural regeneration of Pinus sylvestris var. mongolica plantation on sandy land].

By employing comparison analysis and field survey, the natural regeneration of Mongolian pine plantations on sandy soil was investigated. In plantation areas where regeneration can take place naturally, natural regeneration of Mongolian pine varied temporally and spatially. Natural regeneration wasn't temporally continuous; it had a close relationship with autumn precipitation in particular years. In spatial aspect, there were three regeneration types: regeneration in forest gaps, regeneration on edges of a forest, regeneration under young broadleaf forest. There was no significant difference between the growth of regeneration saplings and plantation trees.

Agriculture↗

PubMed2002

[Analysis of natural regeneration barriers of Pinus sylvestris var. mongolica plantation on sandy land].

By employing comparison analysis, and field experiment of watering and soil-covering before overwintering for seedlings, the barriers of natural regeneration for Mongolian pine plantations on sandy soil were identified. The experimental area was divided into 3 parts according to the state of natural regeneration. Crown closure, litter, understory coverage, and site condition were the factors which affect natural regeneration. Water deficit, but not low temperature during overwintering, is the key factor that limits survival for 1-2 years old seedlings in plantation area. The water deficit is due to higher air temperature, less accumulated snow, higher soil evaporation, higher plant transpiration in plantation area than in the area in which Mongolian pine is naturally distributed. Based on the above research, it is necessary to take effective artificial measures to promote its natural regeneration so as to guarantee its successful development. The following measures are recommended: 1) covering the 1-2 years old seedlings with soil before wintering, 2) irrigating seedlings before wintering, 3) suitable forest harvest, e.g., belt clear-cutting, or patch cutting, 4) planting the pine with broadleaf species, 5) protecting forest stands from livestock grazing, seed collecting and litter gathering.

Desert Climate↗

PubMed2002

[Improvement and application of digitized measure on shelterbelt porosity].

Based on the lots of investigation on farmland shelterbelts, we used digital camera to take pictures of shelterbelt and apply CIAS software to improve "digital image processing" for determining shelterbelt porosity so as to thoroughly analyze the rule of porosity in farmland shelterbelts. Compared with the old digital image processing, the improved method possesses high accuracy, and it is more economical and more convenient to apply. The relationship between porosity of shelterbelts (beta) and relative clear bole height (x) can be expressed as beta = 0.672x0.469 (r = 0.9851, r0.01 = 0.4073, 0 < or = beta < or = 1) in the leaf period; and beta = 1.0681x0.4304 (r = 0.9763, r0.01 = 0.4073, 0 < or = beta < or = 1) in the defoliation period. beta varies with the stand age (a), taking the form of parabola, which can be expressed as beta = 0.0009a2 - 0.0364a + 0.6828 (0 < or = beta < or = 1). Porosity at cross-section of shelterbelt can be used as an auxiliary index to evaluate the structure of belts. The calculation method of shelterbelt porosity of mixed shelterbelt can be expressed as beta = (beta 1n1 + beta 2n2)/(n1 + n2). Among the popular, willow and elm pure shelterbelts with same disposition, popular shelterbelt structure is the best, with beta PPP < beta SSS < beta UUU, while the triangle disposition is better than the rectangle one among the same tree species. UPPU and SPPS of mixed structure have the optimal effect in popular-willow-elm mixed shelterbelts.

Trees↗

PubMed2002

[Sustainable management for farmland shelterbelts].

The spatio-temporal pattern of shelterbelt regeneration is an important issue which determintes whether shelterbelt network produces protective effects sustainably. This article developed a new method of imitating "normal forest" to manage shelterbelts. Based on an administrative village as an organized management unit, each shelterbelt in the organized management unit will be individually regenerated and regulated, until the number of the shelterbelts in each age-class from young to mature ones will be equal, and the shelterbelts in each age-class will be spatially distributed uniformly in the shelterbelt network of an organized management unit. Consequently, this method might temporally ensure sustainable and stable ecological services which are provided by the shelterbelts in an organized management unit.

Agriculture↗

PubMed2002

[Introduction and selection of new poplar clones in shelterbelts/windbreaks in northern Liaoning].

Six new poplar clones were introduced in Qianshuanging township of Changtu county, Liaoning Province as experiment materials, and their indeces in growth, cold resistance, disease infection, and insect infection were evaluated and compared to the locally grown Fuzha II poplar. According to the comparison of the 4 indices, the study found that N-119 poplar showed all the scores obviously better than those of CK and other poplars, and was recommended for the area. The growth of Zhonglin 95 was higher, and its disease and pest infection was equal or near to the CK. So, the poplar Zhonglin 95 is also worthy to be recommended.

Agriculture↗

PubMed2002

[Ecological forecasting: a frontier in ecology].

An evolving science of ecological forecasting is beginning to emerge, and could have an increasingly important role in policy-making and management of natural resources and environment. The progress in computer science, quantitative analysis and ecological theory, together with the application of new high technology, will increase our ability to forecast ecosystem change. The authors introduced the connotation of ecological forecasting, relevant research advances, and some typical examples. Ecological forecasting is an important frontier in ecology, and also, would be an important direction for future ecological study.

Decision Making↗