scholarly journals Soil Moisture Estimation and Its Influencing Factors Based on Temporal Stability on a Semiarid Sloped Forestland

2021 ◽  
Vol 9 ◽  
Author(s):  
Mingzhu Xu ◽  
Guoce Xu ◽  
Yuting Cheng ◽  
Zhiqiang Min ◽  
Peng Li ◽  
...  
Keyword(s):  
Loess Plateau ◽  
Temporal Stability ◽  
Relative Difference ◽  
Root Density ◽  
Sand Content ◽  
The Loess Plateau ◽  
Factors Affecting ◽  
Dry Seasons ◽  
The Mean ◽  
Main Factors

Soil water content (SWC) plays a crucial role in the hydrological cycle and ecological restoration in arid and semi-arid areas. Studying the temporal stability of SWC spatial distribution is a requirement for the dynamic monitoring of SWC and the optimization of water resource management. The SWC in a Pinus tabulaeformis Carr. forest on the slope of the Loess Plateau of China were analyzed in five soil layers (0–100 cm with an interval of 20 cm) in the rainy and dry seasons from July 2014 to November 2017. The mean SWC was estimated and the main factors affecting the temporal stability of the SWC were further analyzed. Results showed that the SWC had strong temporal stability during the two seasons for several consecutive years. The temporal stability of SWC and the number of representative locations varied with season and depth. The elevation, soil total phosphorus (STP), clay, silt, or sand content of the representative locations approached the corresponding mean value of the study area. A single representative location accurately represented the mean SWC for the five depths in the rainy and dry seasons (RMSE <2%; rainy season: 0.81 < R2 < 0.94; dry season: 0.63 < R2 < 0.83; p < 0.01). The mean relative difference (MRD) and the relative difference standard deviation (SDRD) changed with the seasons and were significantly correlated with elevation, root density, and sand and silt content in two seasons (p < 0.05). Elevation, root density, and sand content were the main factors influencing the change of SWC temporal stability in different seasons. The results provide scientific guidance to monitor SWC by using a small number of locations and enrich our understanding of the factors affecting the temporal stability of SWC in the rainy and dry seasons of the Loess Plateau of China.

scholarly journals Response of Kostiakov-Lewis Infiltration Parameters to Soil Physical-Chemical Properties in the Loess Plateau of China

2020 ◽  
Vol 71 (4) ◽  
pp. 581-593
Author(s):  
Wenjing Qin ◽  
Guisheng Fan
Keyword(s):  
Organic Matter ◽  
Water Content ◽  
Bulk Density ◽  
Loess Plateau ◽  
Chemical Properties ◽  
Sand Content ◽  
The Loess Plateau ◽  
Silt Content ◽  
Main Factors ◽  
Infiltration Parameters

In order to know the main factors influence the infiltration parameters, based on the 344 sets of double-ring infiltration experiments in 101 different experimental sites in the Loess Plateau, obtained a large sample of Kostiakov-Lewis infiltration model parameters, analyzed the relationship between infiltration parameters and soil properties, established a multiple linear model, a nonlinear model and a BP neural network model to predict the infiltration parameters. The results showed that through Pearson correlation analysis, the main factors for parameter k was bulk density, soil water content of 0-10 cm, sand content, silt content and organic matter of 0-20 cm, the main factors influence parameter α was water content, sand content, silt content of 0-40 cm, and bulk density of 20-40 cm, and the main factors for parameter f0 was water content, sand content, silt content, of 0-40 cm, bulk density of 10-40 cm, and organic matter of 0-20 cm. Compared with previous studies, this paper added soil organic matter content as an independent variable to study the effect of soil chemical properties on soil infiltration capacity, which makes the model more reasonable, higher accuracy, and better prediction effect. Based on the effective test, result error analysis and comprehensive analysis, it was feasible to obtain the infiltration parameters in the Kostiakov-Lewis model using three Pedo-transfer functions. Under the condition of comprehensive consideration of forecast accuracy and stability applicability, it was recommended to use the nonlinear model as the prediction model of soil water infiltration parameters in the Loess Plateau.

scholarly journals Paleolimnology of Lake Yamanaka as reflected on particle-size distribution

1970 ◽  
Vol 14 ◽  
pp. 35-42 ◽  
Author(s):  
Danda Pani Adhikari
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Size Distribution ◽  
Central Japan ◽  
Size Frequency Distribution ◽  
Factors Affecting ◽  
Mean Grain Size ◽  
The Mean ◽  
Main Factors ◽  
Lake Size

A 17.63 m long bore-hole core extracted from the deepest part of Lake Yamanaka, one of the Fuji-five Lakes at the northeasternfoot of Mount Fuji, central Japan, composed of sediment with intercalations of scoria fallout deposits. The sediment of the upper11.4 m was investigated for grain-size distribution by using a laser diffraction particle size analyser. The mean grain-size profileshowed various degrees of fluctuations, both short-and long-terms, and the size-frequency distribution revealed unimodal-trimodalmixing of sediments. Changes in lake size and water depth appear to be the main factors affecting the variability in the grain-sizedistribution and properties. The lake level appears low during 7000–5000 cal BP and 2800–1150 cal BP and relatively high during5000–2800 cal BP and 1150 cal BP– present.DOI: http://dx.doi.org/10.3126/bdg.v14i0.5437Bulletin of the Department of Geology Vol.14 2011, pp.35-42 

scholarly journals Surface Layer Turbulent Characteristics over the Complex Terrain of the Loess Plateau Semiarid Region

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zhida Zhang ◽  
Jiening Liang ◽  
Min Zhang ◽  
Qi Guo ◽  
Lei Zhang
Keyword(s):  
Surface Layer ◽  
Transfer Coefficient ◽  
Loess Plateau ◽  
Turbulence Intensity ◽  
Complex Terrain ◽  
Semiarid Region ◽  
The Loess Plateau ◽  
Mean Values ◽  
The Mean ◽  
Standard Deviations

Surface layer turbulence has an important influence on land-air interactions and pollutant dispersion, and studying the characteristics of surface layer turbulence in complex terrain can contribute to understanding land-air interactions, improving model surface layer parameterization, and enhancing pollution prediction capabilities. The surface layer turbulence observations from the Semi-Arid Climate and Environment Observatory (SACOL) of Lanzhou University in 2008 were processed in this study. High-quality turbulence parameters were calculated, the statistical and transfer characteristics of turbulence were analyzed, and the formation of turbulence was assessed in terms of dynamics and thermodynamics. The atmospheric stability in the semiarid region of the Loess Plateau is basically dominated by neutral/near-neutral and weakly unstable/weakly stable conditions; this pattern is significantly different from the preponderance of unstable and stable layers at other sites. The turbulence intensity differs significantly in both the horizontal and vertical directions and basically shows the relationship I u ≈ I v > I w . The mean values of I u and I v are 0.42 and 0.40, respectively, and the mean value of I w is 0.14, which is different from the general pattern of I u > I v > I w , indicating that the turbulence intensity at SACOL is characterized by a large lateral wind contribution. The dimensionless standard deviations of the nonneutral wind velocity components satisfy the “1/3rd law,” and the dimensionless standard deviations of u, v , and w components are 3.35, 2.98, and 1.26, respectively, in the semiarid Loess Plateau. These values are larger than those over flat terrain. The contribution of the shear term to the formation of turbulence is greater than that of the buoyancy term, and the mean annual values of the shear term and the buoyancy in the kinetic energy budget equation in SACOL are 47.94 × 10−4 m2·s−3 and 11.32 × 10−4 m2·s−3, respectively. The annual mean values of the momentum transfer coefficient C D and the heat transfer coefficient C H under near-neutral conditions are 8.54 × 10−3 and 2.52 × 10−3, respectively.

Factors Affecting Soil Desiccation Spatial Variability in the Loess Plateau of China

2019 ◽  
Vol 83 (2) ◽  
pp. 266-275 ◽  
Author(s):  
Chunlei Zhao ◽  
Ming'an Shao ◽  
Xiaoxu Jia ◽  
Yuanjun Zhu
Keyword(s):  
Spatial Variability ◽  
Loess Plateau ◽  
The Loess Plateau ◽  
Factors Affecting ◽  
Soil Desiccation

Wastage of conserved fodder when feeding livestock

2010 ◽  
Vol 50 (6) ◽  
pp. 400 ◽  
Author(s):  
C. R. Stockdale
Keyword(s):  
Beef Cattle ◽  
Dairy Cattle ◽  
Present Review ◽  
Factors Affecting ◽  
Storage Method ◽  
The Mean ◽  
Main Factors ◽  
Wet Weather ◽  
The Cost ◽  
The Impact

The objective of the present review was to establish levels of conserved fodder wastage when feeding livestock (sheep, beef cattle, dairy cattle) under various conditions and using various feed-out systems, and to determine the factors affecting wastage. The mean wastage of hay recorded in the literature reviewed was 17% of the DM offered, but the range was from 4 to 77%. The main factors affecting the degree of wastage were storage method, packaging method, method of feeding out, amount of fodder on offer and its palatability and/or quality and the impact of wet weather. Although the emphasis was on hay, the principles should also apply to silage. If wastage was 40% rather than 5%, the cost of feeding conserved fodder to livestock would be a third greater than producers might expect or budget on.

scholarly journals The effects of land-use combinations on soil erosion: a case study in the Loess Plateau of China

2009 ◽  
Vol 33 (6) ◽  
pp. 793-804 ◽  
Author(s):  
Bo-Jie Fu ◽  
Ya-Feng Wang ◽  
Yi-He Lu ◽  
Chan-Sheng He ◽  
Li-Ding Chen ◽  
...  
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Loess Plateau ◽  
Soil Layer ◽  
Shaanxi Province ◽  
Land Uses ◽  
The Loess Plateau ◽  
Factors Affecting ◽  
Mature Forest ◽  
Young Forest

Land use is one of the key factors affecting soil erosion in the Loess Plateau of China. This paper examines soil erosion under different land uses and land-use combinations using 137 Cs tracing in the Yangjuangou Catchment, a tributary of the Yan River in the Loess Plateau of Northern Shaanxi Province. The results show that the order of 137Cs activity in different land uses decreases sequentially from mature forest to grass to young forest to orchard to terrace crop, indicating that the mature forests had the lowest erosion rates while the terraced cropland produced the highest erosion amount. The majority of 137Cs is distributed in the top 0—10 cm of the soil layer. The 137Cs activity in mature forest and grass soil is significantly higher than in other land uses. Three land-use combinations on the hillslope were selected to study the relationship between land-use combination and soil erosion. The mixtures of ‘grass (6 years old) + mature forest (25 years old) + grass (25 years old)’ and ‘grass (6 years old) + young forest (6 years old) + mature forest (25 years old) + grass (25 years old)’ are better for soil erosion control, lowering soil erosion amount by 42% compared with a land-use combination of ‘grass (6 years old) and shrub (6 years old)’. The results provide an important basis for optimizing land-use combinations to control soil erosion on slopes and may also result in important ecological benefits.

Studies on some of the physical and biological factors affecting the abundance of the Aedes simpsoni (Diptera: Culicidae) complex-larvae and pupae in plant axils

1994 ◽  
Vol 84 (2) ◽  
pp. 255-263 ◽  
Author(s):  
J. J. Lutwama ◽  
L. G. Mukwaya
Keyword(s):  
Water Content ◽  
Habitat Segregation ◽  
Biological Factors ◽  
Factors Affecting ◽  
Developmental Rates ◽  
Dry Seasons ◽  
The Mean ◽  
Major Factors ◽  
Aedes Simpsoni ◽  
Indices Of Association

AbstractSome physical and biological factors affecting the abundance of larvae and pupae of the Aedes simpsoni (Theobald) complex, in leaf axils of different plants at several locations in Uganda, were investigated during the rainy and dry seasons. The mean number of axils per plant, axils containing larvae and pupae, and the mean number of larvae and pupae per ml of axil water all varied between seasons and locations. The percentage of axils containing larvae and pupae increased with volume of water in the axils of the different plants. The mean number of larvae and pupae per axil containing water also increased with water content of the axils. There was more water in the axils during the rainy than during the dry seasons. The mean temperature of water was lower in Xanthosorna sagittifoliurn (20.4°C) and Colocasia esculentum (22.1°–22.7°C) than in those of banana (25.0°–27.2°C) and this affected developmental rates of larvae and pupae. The indices of association between larvae and pupae of the A. simpsoni complex and Malaya taeniarostris (Theobald) did not indicate competition and there was some habitat segregation between them. The volume and temperature of water in the axils appeared to be the major factors affecting larval and pupal abundance of A. simpsoni in the axils.

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