scholarly journals Spatial Distribution of Stony Desertification and Key Influencing Factors in Different Sampling Scales in Small Karst Watersheds

2018 ◽  
Author(s):  
Zhenming Zhang ◽  
Yunchao Zhou ◽  
Shijie Wang ◽  
Xianfei Huang
Keyword(s):  
Spatial Distribution ◽  
Spatial Variability ◽  
Influencing Factors ◽  
River Basin ◽  
Original Data ◽  
Gis Technology ◽  
Soil Thickness ◽  
Grid Sampling ◽  
Average Value ◽  
Sampling Scale

In this paper, the spatial distribution of stony desertification characteristics and its influencing factors in Karst areas in different sampling scales are studied using a grid sampling method based on geographic information system (GIS) technology and geo-statistics, with the rock bareness rate obtained through sampling with 150m × 150m grids in the Houzhai River Basin being taken as the original data and five grid scales (300m × 300m, 450m × 450m, 600m × 600m, 750m × 750m, and 900m × 900m) as the subsample sets. The results show that the rock bareness rate does not vary much from one sampling scale to another while average values of the five sub-samples all fluctuate around the average value of the entire set. As the sampling scale is expanding, the maximum value and the average value of rock bareness rate are decreasing gradually, with a gradual increase in the coefficient of variability. In the scale of 150m × 150m, the areas of minor stony desertification, medium stony desertification, and major stony desertification in the Houzhai River Basin are 7.81 km2, 4.50 km2, and 1.87 km2, respectively. The spatial variability of stony desertification on small scales is influenced by many factors, and that on medium scales is jointly influenced by gradient, rock contents, and rock bareness rate. On large scales, the spatial variability of stony desertification is mainly influenced by soil thickness and rock bareness rate.

scholarly journals Spatial variability of primary production and chlorophyll in the Laptev sea in august–september

2019 ◽  
Vol 59 (5) ◽  
pp. 755-770
Author(s):  
A. B. Demidov ◽  
V. I. Gagarin ◽  
E. G. Arashkevich ◽  
P. N. Makkaveev ◽  
I. V. Konyukhov ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Spatial Variability ◽  
Primary Production ◽  
Continental Slope ◽  
Incident Radiation ◽  
Laptev Sea ◽  
Phytoplankton Primary Production ◽  
Average Value ◽  
Nutrients Concentration ◽  
The Laptev Sea

Spatial distribution of phytoplankton primary production and chlorophyll was studied based on the data of three cruises carried out in AugustSeptember of 2015, 2017 and 2018. The average value of water column primary production (IPP) along the transect from Lena`s mouth to the continental slope was 2.8 fold higher than that one along the transect from Khatanga`s mouth, which was explained by the level of incident radiation and nutrients concentration. Along the cross-slope transects increasing of photosynthetically layer integrated chlorophyll (Chlph) occurred due to developing of deep maxima. IPP and Chlph increasing was registered in the vicinity of the continental slope. In AugustSeptember the averaged IPP value was 100 mgC m-2 d-1 that is the evidence of oligotrophy of the Laptev Sea at the end of summer and at the beginning of autumn.

Evaluation of the Ecological Security in Shiyang River Basin Based on Grid GIS and PSR Model

2013 ◽  
Vol 864-867 ◽  
pp. 1042-1046
Author(s):  
Wei Wei ◽  
Bin Bin Xie
Keyword(s):  
Spatial Distribution ◽  
River Basin ◽  
Evaluation System ◽  
Principal Component ◽  
Ecological Security ◽  
Gis Technology ◽  
Weighting Method ◽  
Shiyang River Basin ◽  
Landscape Patches ◽  
Regional Ecology

With the support of GIS technology, in this paper, each index in the evaluation system was set to the spatial expression of 100m×100m grid scale. Subsequently, the spatial principal component analysis and hierarchy process-combination weighting method were used to express the spatial distribution of regional ecology security in study area. Some results show that:(1)The spatial distribution differences of regional ecology security are very obvious. (2)The maximum of SESI is 87.14 in Liangzhou District and its surroundings. Comparatively, the minimum value is 43.96 in north Minqin and edge of Tengery desert. This weakens interaction on ecological flowing in the basin as well as the capacity of ecological restoration between landscape patches. So the polarization of the watershed ecological security will become more seriously. (3)The ecological security and sustainable development of Shiyang River Basin are still in class of III(Threaten security) and class IV(insecurity).

scholarly journals The Research on Temporal–Spatial Distribution and Morphological Characteristics of Ancient Settlements in the Songhua River Basin

2019 ◽  
Vol 11 (3) ◽  
pp. 932 ◽  
Author(s):  
Meng Zhu ◽  
Jianfei Dong ◽  
Yingzhi Gao
Keyword(s):  
Spatial Distribution ◽  
River Basin ◽  
Morphological Characteristics ◽  
Cultural Value ◽  
Gis Technology ◽  
Songhua River ◽  
Songhua River Basin ◽  
Human Habitation ◽  
The Songhua River Basin ◽  
The Songhua River

Settlements have a high cultural and historical value in regions as indicators of human habitation and culture. The Songhua River Basin is on the edge of a traditional cultural center, which has scattered ecological elements, a special culture, and historical faults. Because of the superposition of traces of different ethnic activities in different periods, the Songhua River has a special and diversified cultural foundation and heritage, which is of high research value. However, the ancient settlements in this region have not been given sufficient attention and as a result it is difficult to achieve a complete and systematic study. In order to promote the cultural value of this historical region and the development of a regional and cultural industry, this paper seeks to study the ancient settlements of Songhua River Basin. With the help of GIS technology, archeological excavations, and the concept of ethnic pedigree in ethnology, this study analyzes the temporal–spatial distribution and morphological characteristics of ancient settlements in the Songhua River Basin, in order to determine how the heritage value of these settlements can be sustainably protected.

scholarly journals Spatial Distribution of the Dagger Nematode Xiphinema index and Its Associated Grapevine fanleaf virus in French Vineyard

2008 ◽  
Vol 98 (8) ◽  
pp. 942-948 ◽  
Author(s):  
L. Villate ◽  
V. Fievet ◽  
B. Hanse ◽  
F. Delemarre ◽  
O. Plantard ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Virus Disease ◽  
Sampling Procedure ◽  
Horizontal Distribution ◽  
Distribution Data ◽  
Grapevine Fanleaf Virus ◽  
Neighborhood Structure ◽  
Grid Sampling ◽  
Xiphinema Index ◽  
Sampling Scale

The nematode Xiphinema index is, economically, the major virus vector in viticulture, transmitting specifically the Grapevine fanleaf virus (GFLV), the most severe grapevine virus disease worldwide. Increased knowledge of the spatial distribution of this nematode, both horizontally and vertically, and of correlative GFLV plant infections, is essential to efficiently control the disease. In two infested blocks of the Bordeaux vineyard, vertical distribution data showed that the highest numbers of individuals occurred at 40 to 110 cm depth, corresponding to the two layers where the highest densities of fine roots were observed. Horizontal distribution based on a 10 × 15 m grid sampling procedure revealed a significant aggregative pattern but no significant neighborhood structure of nematode densities. At a finer scale (≈2 × 2 m), nematode sampling performed in a third block confirmed a significant aggregative pattern, with patches of 6 to 8 m diameter, together with a significant neighborhood structure of nematode densities, thus identifying the relevant sampling scale to describe the nematode distribution. Nematode patches correlate significantly with those of GFLV-infected grapevine plants. Finally, nematode and virus spread were shown to extend preferentially parallel to vine rows, probably due to tillage during mechanical weeding.

scholarly journals Soil attributes and weed seedbank spatial correlation

2019 ◽  
Vol 35 (6) ◽  
Author(s):  
Ígor Araujo Menezes De Avila ◽  
Sandro Manuel Carmelino Hurtado ◽  
Gabriel Camargo De Jezus ◽  
Gustavo Costa Silva ◽  
Matheus Mendes Rezende
Keyword(s):  
Spatial Distribution ◽  
Spatial Variability ◽  
Crop Yield ◽  
Yield Potential ◽  
Soil Attributes ◽  
Average Value ◽  
Chemical Attributes ◽  
Reducing Costs ◽  
Herbicide Management ◽  
Physical And Chemical

The crop yield potential is affected by the crop-weed competition and their control create a dependence on herbicide use who brings, as consequence, soil impacts. Knowing the weed’s spatial distribution on the field is a feasible alternative for improving the crop yield. The goal of this paper is the identification of the spatial variability on physical and chemical attributes of soil as well as the weed’s seedbank so that, when correlated, may find standards to help on field management. The experiment was conducted on Uberlandia Federal University premises at soybean no-till area. Using georeferenced soil samples, were analyzed the physical and chemical attributes as well as the weed’s seedbank. The weed population on controlled environment was quantify, sorting out broadleaf and grassy weeds species. The obtained data were analyzed by descriptive statistic and geostatistics for a semivariogram modeling, interpolation by the kriging methodology and the spatial variability maps achievement. The average value, coefficient of variation (CV%), asymmetry, kurtosis coefficient and the significant linear correlations interfered on data spatial variability which we concluded by the spatial dependences on the attributes that had a linear correlation between them. The semivariograms presented varied range between 202 to 752 meters. Using the maps, verified two different regions for the broadleaf and grassy weeds seedbank. For both situations there was influence by the soil attributes on infestation level, which makes it possible to target the herbicide management reducing costs and the environmental impact. From the analyzed data we conclude that there is a spatial dependence for the physical and chemical soil attributes and their spatial distribution explains the weed seedbank spatial variability.

Spatial variability of imazethapyr sorption in soil

Weed Science ◽  
1999 ◽  
Vol 47 (2) ◽  
pp. 243-248 ◽  
Author(s):  
Rubem S. Oliveira ◽  
William C. Koskinen ◽  
Francisco A. Ferreira ◽  
Bhairav R. Khakural ◽  
David J. Mulla ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Organic Carbon ◽  
Spatial Variability ◽  
Soil Properties ◽  
Large Field ◽  
Site Specific ◽  
Average Value ◽  
Measured Property ◽  
Ph Range ◽  
Representative Samples

A significant limitation in using sorption coefficients (Kd) to predict solute transport through natural soils is the spatial variability of soil properties over large field areas. Spatial variability inKdfor imazethapyr was determined on representative samples from a 31.4-ha field, covering a pH range from 4.9 to 7.6 and an organic carbon (OC) range from 1.45 to 5.80 g kg−-1.Kdvaried from 0.18 to 3.78 across the field, with an average value of 1.56. The analysis ofKdvariability showed two distinct patterns in spatial distribution: areas in which pH > 6.25 andKd< 1.5, whereKdvariation is based primarily on pH, and areas in which pH < 6.25 andKd> 1.5, where other soil properties, i.e., OC content, have a significant influence onKdvariation. Based on soil pH distribution, an easily measured property, the field was divided into two potential management areas. This separation allowed identification of portions of the field where herbicide sorption would be minimal, with a relatively higher potential for leaching (i.e., areas withKd< 1.5), and provided a rationale for site-specific imazethapyr application.

scholarly journals Two-Step Measurement of Water–Energy–Food Symbiotic Coordination and Identification of Key Influencing Factors in the Yangtze River Basin

Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 798
Author(s):  
Weizhong Chen ◽  
Yan Chen
Keyword(s):  
Sustainable Development ◽  
Influencing Factors ◽  
River Basin ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
Measurement Model ◽  
Primary Energy ◽  
The Yangtze River ◽  
Average Value ◽  
The Yangtze River Basin

With the intensification of people’s production and life behaviors, the systemic risks of water, energy and food in the Yangtze River Basin have become increasingly prominent, which has become a bottleneck for sustainable development of social, economic and ecological in the basin. Therefore, studying the symbiotic coordination between water, energy and food is of great significance to promoting regional sustainable development. First, from the perspective of water–energy–food symbiosis, with the water–energy–food ecosystem conceptual model as the nexus, the two-step measurement model of the symbiotic index and the symbiotic level index is used to study the water–energy–food symbiosis of the Yangtze River. Then, we use the BP-DEMATEL-GTCW model to identify the key influencing factors that affect the symbiotic security of the water–energy–food ecosystem. In this research, it is found that the average value of the symbiotic degree of the water–energy–food ecosystem of the 11 provinces or municipalities in the Yangtze River Basin only reached the risk grade. It can also be seen from the identification results of key influencing factors that energy microsystem-related indicators have a greater impact on the symbiotic development of the entire WEF ecosystem. Therefore, special attention needs to be paid to increasing energy sources and reducing expenditure. Relevant departments need to effectively develop primary energy production and expand energy-saving investment through multiple channels to expand energy self-sufficiency and ultimately promote the coordinated and effective development of water, energy and food in the Yangtze River Basin.

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