基于GIS的农村居民点空间分布特征研究----以扶余市为例     

王智颖 《现代农业科技》2023,(21)

科学认识乡村地域结构是全面推进农业农村现代化和乡村振兴的基础。本文以扶余市第二次土地调查调数据为基础，借助ArcGIS空间分析软件，运用规模分析、核密度估算、缓冲区分析，从用地规模、分布格局与土地利用条件方面探讨扶余市农村居民点地域分异特征。研究表明：扶余市以微、小型居民点居多，居民点数量随着规模的增大逐渐减少，居民点之间的距离差异较大，总体呈现大散居、小聚居，不均匀分散分布；农村居民点的平均核密度为0.4个/km2，空间布局呈东南部高密度集聚成片，向西逐渐密度降低，西部零散错落分布；居民点分布呈现较强的城镇指向性，交通用地对居民点有集聚的作用，河流对微型居民点和大型居民点有集聚吸引的功能。  相似文献   

邛海盆地土壤氮素空间变异特征与影响因素研究   总被引：1，自引：0，他引：1  

胡玉福  邓良基  肖海华  舒向阳  黄成毅  罗澜芳 《农业机械学报》2015,46(4):132-140

以西昌市邛海盆地为研究区域,随机均匀布点采集386个耕作层土壤样点,分析化验土壤理化性质,运用地统计学方法和GIS技术研究邛海盆地表层土壤氮素含量的空间变异特征,利用方差分析、缓冲区分析和回归分析定量分析区域内土壤氮素空间变异的影响因素。研究结果表明,研究区表层土壤全氮和速效氮含量分别为(1.85±0.51)g/kg和(138.5±47.7)mg/kg,属较丰富水平,变异系数分别为27.52%和32.24%,属中等差异强度;土壤全氮和速效氮具有中等程度的空间相关性,空间变异均以随机变异为主,具有各向异性特征,在西北-东南方向上空间变异相对剧烈;研究区土壤全氮和速效氮含量总体上呈条带状或斑块状分布特征,高值区主要位于西昌市的东南郊区,并以此高值中心向南、向东和向北3个方向逐步递减,低值区主要出现在邛海北面近湖岸地带。影响因素分析结果表明,土地利用方式、土壤母质、土壤质地、土壤p H值、城镇、河流、邛海湖对土壤全氮和速效氮空间变异具有显著影响,而道路对土壤氮素空间变异影响不显著。  相似文献   

景观生态格局分析在风景园林规划中的应用     

申亮  王葆华 《安徽农业科学》2011,39(29):18036-18037,18040

景观生态格局模式强调景观空间格局对过程的控制和影响,并通过格局的改变来维持景观功能流的健康与安全。景观生态格局的研究方法有静态分析法和动态分析法。利用生态安全格局方法去建立整体性的生态基础设施是城市生态环境规划的基础,它为建设生态城市提供了理论基础和实践方法,可应用于分析城市的景观生态基本特征、城市的景观安全格局现状,规划城市景观生态格局。该研究以西安市为例,采用景观格局指数静态分析法分析了西安的生态环境及景观生态格局构成,归纳出西安市生态基质、廊道和斑块的分布及其特点,并就其中存在的基质形态破碎化、廊道人工化、建成区内斑块分散化问题进行了总结,以期为今后的西安市生态格局研究和完善提供理论基础。  相似文献   

Herbicide savings and economic benefits of several strategies to control Sorghum halepense in maize crops     

《Crop Protection》2013

This study was conducted to assess the herbicide savings and the cost efficiency of site-specific herbicide application strategies in comparison with other strategies based on uniform application of herbicides throughout the whole field. The specific situation considered was Sorghum halepense infested maize fields in Spain. The results from a theoretical economic model were contrasted with the information derived from a S. halepense survey conducted in 37 commercial maize fields distributed over three Spanish maize production areas. Seven application strategies were simulated: 1) no herbicide; 2) overall full-rate; 3) overall half-rate; 4) and 5) site-specific spraying infested cells with full- and half-rate, respectively; 6) and 7) site-specific spraying infested cells plus adjacent buffer areas with full- and half-rate, respectively. The simulation results showed that site-specific weed management was the most profitable strategy when S. halepense infested area ranged between 6.5 and 18.7%. This scenario was present in 22% of the surveyed fields. In fields with less than 6.5% infestation (a situation present in 51% of the surveyed fields), yield losses were slight and the most profitable strategy was using no herbicide. When the infested area ranged between 18.7 and 40.8% (19% of the surveyed fields), no significant differences were observed between the net benefits of the various strategies. Full rate herbicide applications throughout the entire field resulted in the highest net returns in fields with more than 40.8% weed infestation (8% of the surveyed fields). In these cases, the added costs of weed detection, mapping and site-specific herbicide application were not justified by the herbicide savings obtained. Likewise, herbicide savings obtained with the various strategies depended on the proportion of the field infested. Considering the high difference between site-specific treatments and uniform application of herbicides when the infested area ranged between 18.7 and 40.8%, and that no significant differences in net returns were observed in this range, site-specific treatments should be preferred. Adding a buffer area to the site-specific treatments does not seem a suitable strategy due to the considerable increases in costs and reductions in herbicide savings.  相似文献   

Forest resources variation along with the main rivers in typical forest region of Changbai Mountain   总被引：1，自引：0，他引：1  

Hao?Zhan-qingEmail author  Yu?De-yong  Lin?Fan  Xiong?Zai-ping  Ye?Ji 《林业研究》2004,15(2):101-106

The restoration of the riparian vegetation disturbed by human activities is one of the hotspots of watershed ecology. Through interpreting the images of Remote Sensing in 1985 and 1999, the basic information of forest resources of Lushuhe Forest Bureau, which is a typical forest area of Chanbai Mountain was obtained with support of GIS. By dividing Land covers of Lushuihe area into 10 types (water body, residential land, stump land, farming land, wetland, mature conifer forest, midlife conifer forest, mature broadleaf forest, midlife broadleaf forest, and man-made young forest) and dividing the riparian zone into four buffers (in turn 1000, 2000, 3000, 4000 m away from the river), the changes of riparian forest resources during 1985–1999 were analyzed. The results showed that the deforestation intension has obviously decreased and the whole environment has been evidently improved, but the riparian ecosystem was still flimsy. In buffer 1, 2, 3 the area of midlife conifer forest increased largely, but the areas of other types of land covers all decreased. Midlife conifer forest had a comparatively good status in the three buffers. In buffer 4, midlife conifer forest, mature conifer forest, and mature broadleaf forest formed a forest-age rank that is helpful to stabilize the forest ecosystem and exert its functions. Area percentage of wetland decreased in buffer 1, buffer 2, and buffer 3, even in buffer 4 in which forest ecosystem rehabilitated comparatively well, so protecting and rehabilitating wetland is a very difficult task. Foundation item: This study is supported by major projects of Knowiedge Innovation Program. Chinese Academy of Sciences (No. KZCX2-SW-320-3) and Institute of Applied Ecology (a grant SCXZD010-01), CAS. Biography: HAO Zhan-qing (1962-), Male, Ph. Doctor, Professor in Institute of Applied Ecology, Chinese Academy of Science, Shenyang 1100016, P.R. China Responsible editor: Chai Ruihai  相似文献   

An In Vitro Investigation into the Effects of a Marine-Derived,Multimineral Supplement in Simulated Equine Stomach and Hindgut Environments     

Meriel Moore-Colyer  Denise M. O'Gorman  Katherine Wakefield 《Journal of Equine Veterinary Science》2014

Management of the performance horse often incorporates meal feeding of highly digestible starches and reduced access to high-fiber forage. Such regimens are associated with equine gastric ulceration syndrome (EGUS) and can alter hindgut homeostasis. In-feed buffering of gastric contents and promotion of energy derivation from high-fiber forage in the hindgut are therefore desirable properties of a nutritional supplement. A marine-derived, multimineral supplement with known buffering properties containing calcium, magnesium, and short-chain fructo-oligosaccharides (scFOS) was tested under in vitro simulations of equine stomach and hindgut conditions. Six fiber:concentrate diets were incubated for 4 hours with or without the supplement at 37°C in pepsin HCl solution adjusted to pH 4.1 and 2.6. pH was measured at 1, 2, and 4 hours postincubation. Highest overall pH values were observed with the high cereal feeds; however, the supplement significantly increased (P < .001) the pH across all feeds by 0.17 and 0.19 for feeds incubated at pH 4.1 and 2.6, respectively. A gas production technique was used to measure the fermentation of four fiber:concentrate diets with and without additional supplement, using equine feces as the microbial inoculum. Addition of the supplement decreased (P < .05) the lag time and increased the initial fermentation rate, although as the incubation continued, this effect was reduced. These results demonstrate that the supplement had a significant buffering action for 4-6 hours under simulated in vitro stomach digestion conditions and also stimulated in vitro hindgut fermentation activities.  相似文献   

The buffer effect of non-breeding birds and the timing of farmland bird declines     

Sarah E.A.Le V.dit Durell  Ralph T Clarke 《Biological conservation》2004,120(3):375-382

Breeding territoriality in birds means that a certain proportion of the adult population may breed in suboptimal habitats or not breed at all. Non-breeding birds, or floaters, can have a `buffer effect' on breeding population size. Farmland bird declines in Britain are measured and analysed in terms of numbers of territory-holding birds. We use a population dynamics model to illustrate how, because of the buffer effect of floaters, there can be a time lag between the start of total population decline and detectable breeding population decline. Differences in the timing of declines of closely related farmland birds could therefore be due to slight differences in their population dynamics, rather than differences in their response to agricultural change.  相似文献   

Testing a key assumption of wildlife buffer zones: is flight initiation distance a species-specific trait?     

Daniel T. Blumstein 《Biological conservation》2003,110(1):97-100

The distance at which animals flee an approaching predator is known as the ‘flight initiation distance’ (FID). Wildlife managers use FID to develop buffer zones to reduce human impacts on wildlife. Many variables have been demonstrated to influence FID leading one to question whether it can be viewed as a species-specific trait. We tested this critical assumption for developing buffer zones by experimentally approaching eight species of shorebirds found at six sites around Botany Bay, 15 km south of Sydney, Australia. Botany Bay encompasses a range of human impacted areas, from urban developments with high levels of human presence, through to National Parks and wildlife protection areas where human presence is significantly lower. We found that both species and site influenced the distance birds flew away from an approaching human. Importantly, however, there was no significant statistical interaction between site and species demonstrating that ‘flighty’ species were consistently flighty while more tolerant species were consistently tolerant. Taken together, these results suggest that FID can therefore be viewed as a species-specific trait for these shorebirds. The great variability in FID suggests that wildlife managers should be somewhat conservative in developing buffer zones, but they can use previously published FID data for a given species as guidelines for setting buffer zones.  相似文献   

Rescue of the Seychelles warbler on Cousin Island, Seychelles: the role of habitat restoration     

Jan Komdeur  Mariëtte D. Pels 《Biological conservation》2005,124(1):15-26

Management policies to save threatened species are not always successful, often due to the lack of a scientific basis and evaluation of the species response. We describe the ecological studies and the conservation actions taken between 1985 and 1992 on Cousin Island (29 ha, Seychelles) to safeguard the future of the highly threatened Seychelles warbler (Acrocephalus sechellensis), which until 1988 only occurred on this island. A detailed field study was designed to (1) identify the key processes influencing warbler demography, (2) identify appropriate management techniques to increase the warbler population, and (3), assess the influence of the resulting habitat management. Since 1980 the island has been saturated with c. 115 territories and c. 320 birds. The warbler is purely insectivorous. Morinda (Morinda citrifolia), the most insect rich tree, is preferred for foraging. The higher the insect abundance (and Morinda cover) in territories the higher the reproductive success and survival of warblers. Insect numbers were highest in the central part of Cousin and decreased towards the coast. Coastal territories protected by a salt tolerant hedge of Scaevola (Scaevola taccada) had more insects and higher reproductive success than unprotected territories. Between 1990 and 1992 Morinda trees were planted on the island and Scaevola along the coast. Although these habitat restoration measures have not resulted in higher numbers of adult warblers and territories due to habitat saturation, they have been successful in terms of improving the quality of existing breeding territories and with that the reproductive success of breeding birds (including the number of territories producing recruits), and the exchange of individuals (genetic material) between territories. We provide evidence that the high reproductive potential of this species is likely to improve the resilience of the species to catastrophic events.  相似文献   

不同酸性物质对石灰性土壤的酸化效果研究   总被引：3，自引：1，他引：3  

姚晓芹  马文奇  楚建周 《中国生态农业学报》2006,14(4):68-71

采用室内模拟试验研究了酸性物质对石灰性土壤的酸化效果。结果表明,磷酸能有效地降低石灰性土壤的pH,要使土壤pH由8.89降至6.0左右,最佳酸用量为3.27g/100g土。对于pH较高的石灰性土壤,只用低pH(pH=5.5)的酸水溶液在短时间内降低土壤pH是不切实际的。磷酸二氢铵不仅具有很好的酸化效果,且具有很好的缓冲性能,每100g土壤加入2.3g磷酸二氢铵可使石灰性土壤pH从8.89降低到6.39,并能维持较长的酸性环境。施用5%的硫磺可在30d内使土壤pH降低到7.0～7.5之间。  相似文献