scholarly journals Hydraulic characteristics of plow pan constructed sandy paddy soil by adding fly ash

2021 ◽  
pp. 993-1002
Author(s):  
Yang Wei ◽  
Nan Lu ◽  
Bo Yan ◽  
Gang Li
Keyword(s):  
Fly Ash ◽  
Hydraulic Conductivity ◽  
Water Content ◽  
Paddy Soil ◽  
Storage Capacity ◽  
Water Storage ◽  
Saturated Hydraulic Conductivity ◽  
Wetting Front ◽  
Movement Rate ◽  
Water Storage Capacity

The feasibility of mixing fly ash to sandy soil to build the artificial plow pan of paddy soil in the Yellow River beach was explored. Water infiltration characteristics, saturated hydraulic conductivity, saturated water content and water storage capacity of the artificial plow pan were measured by using laboratory column tests. The results showed that under the same bulk density, when the amount of fly ash increased, the movement rate of the plow pan wetting front, the infiltration rate and the saturated hydraulic conductivity were decreased, then the water content and water storage of the soil layer increased. When the application amount of the fly ash was the same, and when the compaction weight decreased, the wetting front movement rate and saturated hydraulic conductivity increased and the soil water content and water storage capacity decreased. Mixing of fly ash with sand at a ratio of 1:3 (by weight) was found to be ideal for making an artificial of plow pan having bulk density of 1.7 g/cm3. Bangladesh J. Bot. 50(3): 993-1002, 2021 (September) Special  

Einfluss der Wurzeln auf das Wasserspeichervermögen hydromorpher Waldböden | Significance of roots for soil water storage capacity of hydromorphic forest soils

2010 ◽  
Vol 161 (12) ◽  
pp. 510-516 ◽  
Author(s):  
Benjamin Lange ◽  
Peter F. Germann ◽  
Peter Lüscher
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Water Flow ◽  
Forest Soils ◽  
Storage Capacity ◽  
Water Storage ◽  
Contact Length ◽  
Time Domain Reflectometry ◽  
Root Density ◽  
Water Storage Capacity

In this study we investigated the significance of roots for the water storage capacity of hydromorphic forest soils in the northern Pre-Alps of Switzerland. Irrigation experiments were conducted on 1 m2 plots with high initial soil water content. A total of 67 horizons were investigated for water content variations using time domain reflectometry (TDR). The data was processed using a physically based model, which assumes gravity-driven and viscosity-controlled water flow along pore walls in the form of thin water films. The model calculates the contact length (L) between mobile water and the stationary parts of the soil water system in the horizontal plane. L characterises porosity which is effectively involved in water flow. A multiple linear regression analysis of all investigated horizons, including root density, bulk density and texture as predictors for L, demonstrated that the root density had the best explanatory value for L (R2 = 0.63). Thus, it can be assumed that increases in root density increase water storage capacity. Considering the extent of hydromorphicity in horizons, the relationship between root density and contact length was only significant in topsoils and hydromorphic subsoils. An increase of root density by 50% in hydromorphic subsoils would increase short-time water storage capacity from 0.03 to 0.05 m3/m3, while higher root densities in topsoils did not increase water storage capacities. To improve the water retention potential of flood protection forests on hydromorphic soils, we suggest promoting deep-rooting species which are able to sustain anaerobic periods in soils.

scholarly journals Laboratory model test study of the hydrological effect on granite residual soil slopes considering different vegetation types

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jie Chen ◽  
Xue-wen Lei ◽  
Han-lin Zhang ◽  
Zhi Lin ◽  
Hui Wang ◽  
...  
Keyword(s):  
Root System ◽  
Heavy Rainfall ◽  
Storage Capacity ◽  
Water Storage ◽  
Laboratory Model ◽  
Residual Soil ◽  
Vegetation Types ◽  
Water Storage Capacity ◽  
Granite Residual Soil ◽  
Stem Leaf

AbstractThe problems caused by the interaction between slopes and hydrologic environment in traffic civil engineering are very serious in the granite residual soil area of China, especially in Guangdong Province. Against the background of two heavy rainfall events occurring during a short period due to a typhoon making landfall twice or even two typhoons consecutively making landfall, laboratory model tests were carried out on the hydrological effects of the granite residual soil slope considering three vegetation types under artificial rainfall. The variation in slope surface runoff, soil moisture content and rain seepage over time was recorded during the tests. The results indicate that surface vegetation first effectively reduces the splash erosion impact of rainwater on slopes and then influences the slope hydrological effect through rainwater forms adjustment. (1) The exposed slope has weak resistance to two consecutive heavy rains, the degree of slope scouring and soil erosion damage will increase greatly during the second rainfall. (2) The multiple hindrances of the stem leaf of Zoysia japonica plays a leading role in regulating the hydrological effect of slope, the root system has little effect on the permeability and water storage capacity of slope soil, but improves the erosion resistance of it. (3) Both the stem leaf and root system of Nephrolepis cordifolia have important roles on the hydrological effect. The stem leaf can stabilize the infiltration of rainwater, and successfully inhibit the surface runoff under continuous secondary heavy rainfall. The root system significantly enhances the water storage capacity of the slope, and greatly increases the permeability of the slope soil in the second rainfall, which is totally different from that of the exposed and Zoysia japonica slopes. (4) Zoysia is a suitable vegetation species in terms of slope protection because of its comprehensive slope protection effect. Nephrolepis cordifolia should be cautiously planted as slope protection vegetation. Only on slopes with no stability issues should Nephrolepis cordifolia be considered to preserve soil and water.

scholarly journals Urban water storage capacity inferred from observed evapotranspiration recession

2021 ◽  
Author(s):  
Harro Joseph Jongen ◽  
Gert-Jan Steeneveld ◽  
Jason Beringer ◽  
Andreas Christen ◽  
Krzysztof Fortuniak ◽  
...  
Keyword(s):  
Storage Capacity ◽  
Water Storage ◽  
Urban Water ◽  
Water Storage Capacity

Urban water storage capacity inferred from observed evapotranspiration recession 

2021 ◽  
Author(s):  
Harro Jongen ◽  
Gert-Jan Steeneveld ◽  
Jason Beringer ◽  
Krzysztof Fortuniak ◽  
Jinkyu Hong ◽  
...  
Keyword(s):  
Storage Capacity ◽  
Water Storage ◽  
Urban Water ◽  
Natural Forests ◽  
Local Climate ◽  
Water Storage Capacity ◽  
Vegetation Fraction ◽  
Local Climate Zones ◽  
Order Of Magnitude ◽  
Neighborhood Scale

<p>The amount and dynamics of urban water storage play an important role in mitigating urban flooding and heat. Assessment of the capacity of cities to store water remains challenging due to the extreme heterogeneity of the urban surface. Evapotranspiration (ET) recession after rainfall events during the period without precipitation, over which the amount of stored water gradually decreases, can provide insight on the water storage capacity of urban surfaces. Assuming ET is the only outgoing flux, the water storage capacity can be estimated based on the timescale and intercept of its recession. In this paper, we test the proposed approach to estimate the water storage capacity at neighborhood scale with latent heat flux data collected by eddy covariance flux towers in eleven contrasting urban sites with different local climate zones, vegetation cover and characteristics and background climates (Amsterdam, Arnhem, Basel, Berlin, Helsinki, Łódź, Melbourne, Mexico City, Seoul, Singapore, Vancouver). Water storage capacities ranging between 1 and 12 mm were found. These values correspond to e-folding timescales lasting from 2 to 10 days, which translate to half-lives of 1.5 to 7 days. We find ET at the start of a drydown to be positively related to vegetation fraction, and long timescales and large storage capacities to be associated with higher vegetation fractions. According to our results, urban water storage capacity is at least one order of magnitude smaller than the known water storage capacity in natural forests and grassland.</p>

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