scholarly journals Experimental Investigation of Lateral Subsurface Flow Depending on Land Use and Soil Cultivation

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 766
Author(s):  
Sonja Teschemacher ◽  
Wolfgang Rieger ◽  
Markus Disse
Keyword(s):  
Land Use ◽  
Soil Moisture ◽  
Field Experiments ◽  
Response Times ◽  
Subsurface Flow ◽  
Horizontal Distribution ◽  
Forest Site ◽  
Stream Discharge ◽  
Flow Generation ◽  
Grassland Site

The magnitude and timing of flood events are influenced by surface and subsurface flow generation as well as by present land use distribution. An integrated understanding of the interactions of soil properties, land use and flow generation is still missing. Therefore, field experiments are required to gain further knowledge about land use dependencies of discharge generation and concentration processes. In our research, we built an experimental setup consisting of three sites with similar soil and topographic conditions and different land use types (cropland, grassland, forest). The applied multimethod approach includes meteorological parameters, soil moisture, soil moisture tension, surface runoff, lateral subsurface flow, and stream discharge observations. The results show that low subsurface flow discharges more often occur at the cropland site, while large flow volumes were mainly observed at the grassland site. A correlation of the horizontal distribution of subsurface flow volumes and the accumulation areas of the surface topography has been found (r² = 0.76). The observed average response times for advective events increase from the forest site (6.0 h) to the grassland site (12.4 h) to the cropland site (20.9 h). Response times of convective events were shorter than 1 h at all sites.

scholarly journals Influence of Land Cover and Soil Moisture on the Horizontal Distribution of Sensible and Latent Heat Fluxes in Southeast Kansas during IHOP_2002 and CASES-97

2007 ◽  
Vol 8 (1) ◽  
pp. 68-87 ◽  
Author(s):  
Margaret A. LeMone ◽  
Fei Chen ◽  
Joseph G. Alfieri ◽  
Mukul Tewari ◽  
Bart Geerts ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Latent Heat ◽  
Land Surface ◽  
Field Experiments ◽  
Time Of Day ◽  
Horizontal Distribution ◽  
Heat Fluxes ◽  
Surface Model ◽  
Green Vegetation ◽  
The Impact

Abstract Analyses of daytime fair-weather aircraft and surface-flux tower data from the May–June 2002 International H2O Project (IHOP_2002) and the April–May 1997 Cooperative Atmosphere Surface Exchange Study (CASES-97) are used to document the role of vegetation, soil moisture, and terrain in determining the horizontal variability of latent heat LE and sensible heat H along a 46-km flight track in southeast Kansas. Combining the two field experiments clearly reveals the strong influence of vegetation cover, with H maxima over sparse/dormant vegetation, and H minima over green vegetation; and, to a lesser extent, LE maxima over green vegetation, and LE minima over sparse/dormant vegetation. If the small number of cases is producing the correct trend, other effects of vegetation and the impact of soil moisture emerge through examining the slope ΔxyLE/ΔxyH for the best-fit straight line for plots of time-averaged LE as a function of time-averaged H over the area. Based on the surface energy balance, H + LE = Rnet − Gsfc, where Rnet is the net radiation and Gsfc is the flux into the soil; Rnet − Gsfc ∼ constant over the area implies an approximately −1 slope. Right after rainfall, H and LE vary too little horizontally to define a slope. After sufficient drying to produce enough horizontal variation to define a slope, a steep (∼−2) slope emerges. The slope becomes shallower and better defined with time as H and LE horizontal variability increases. Similarly, the slope becomes more negative with moister soils. In addition, the slope can change with time of day due to phase differences in H and LE. These trends are based on land surface model (LSM) runs and observations collected under nearly clear skies; the vegetation is unstressed for the days examined. LSM runs suggest terrain may also play a role, but observational support is weak.

scholarly journals Evaporation from Scots pine (Pinus sylvestris) following natural re-colonisation of the Cairngorm mountains, Scotland

2000 ◽  
Vol 4 (3) ◽  
pp. 451-461 ◽  
Author(s):  
Atul H. Haria ◽  
David J. Price
Keyword(s):  
Land Use ◽  
Soil Moisture ◽  
Water Balance ◽  
Pinus Sylvestris ◽  
Scots Pine ◽  
Forest Canopy ◽  
Physical Structure ◽  
Forest Site ◽  
Natural Forests ◽  
Canopy Interception

Abstract. Recently, changing land-use practices in the uplands of Scotland have resulted in increased re-colonisation of wet heath moorland by natural Scots pine (Pinus sylvestris) woodland. The simple semi-empirical water use model, HYLUC, was used to determine the change in water balance with increasing natural pine colonisation. The model worked well for 1996. However, values of soil moisture deficit simulated by HYLUC diverged significantly from measurements in 1997 when rainfall quantity and intensities were less. Measured interception by the forest canopy (interception by the undergrowth was not measured) was very different from HYLUC simulated values. By changing interception parameters to those optimised against measured canopy interception, HYLUC simulated changing soil moisture deficits better and gave more confidence in the resulting transpiration values. The results showed that natural pine woodland interception may be similar to plantation stands although the physical structure of the natural and plantation forests are different. Though having fewer storage sites for interception in the canopy, the natural pine woodland had greater ventilation and so evaporation of intercepted rainfall was enhanced, especially during low intensity rainfall. To understand the hydrological changes that would result with changing land-use (an expansion of natural forests into the wet heath land), the modelled outputs of the wet heath and mature forest sites were compared. Evaporation, a combination of transpiration and interception, was 41% greater for the forest site than for the wet heath moorland. This may have significant consequences for the rainfall-runoff relationship and consequently for the hydrological response of the catchment as the natural woodland cover increases Keywords: Evaporation; interception; transpiration; water balance; Scots pine; forest

Exploring hydrological processes at a small agricultural catchment in the Czech Republic

2021 ◽  
Author(s):  
Tailin Li ◽  
Nina Noreika ◽  
Jakub Jeřábek ◽  
Tomáš Dostál ◽  
David Zumr
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Hydrological Processes ◽  
Hydraulic Parameters ◽  
Rainfall Runoff ◽  
The Czech Republic ◽  
Mike She ◽  
Stream Discharge ◽  
Soil Hydraulic Parameters ◽  
Soil Hydraulic

<p>A better understanding of hydrological processes in agricultural catchments is not only crucial to hydrologists but also helpful for local farmers. Therefore, we have built the freely-available web-based WALNUD dataset (Water in Agricultural Landscape – NUčice Database) for our experimental catchment Nučice (0.53 km<sup>2</sup>), the Czech Republic. We have included observed precipitation, air temperature, stream discharge, and soil moisture in the dataset. Furthermore, we have applied numerical modelling techniques to investigate the hydrological processes (e.g. soil moisture variability, water balance) at the experimental catchment using the dataset.</p><p>The Nučice catchment, established in 2011, serves for the observation of rainfall-runoff processes, soil erosion and water balance of the cultivated landscape. The average altitude is 401 m a.s.l., the mean land slope is 3.9 %, and the climate is humid continental (mean annual temperature 7.9 °C, average annual precipitation 630 mm). The catchment consists of three fields covering over 95 % of the area. There is a narrow stream which begins as a subsurface drainage pipe in the uppermost field draining the water at catchment. The typical crops are winter wheat, rapeseed, mustard and alfalfa. The installed equipment includes a standard meteorological station, several rain gauges distributed in the area of the basin, and an H flume to monitor the stream discharge, water turbidity and basic water quality indicators. The soil water content (at point scale) and groundwater level are also recorded. Recently, we have installed two cosmic-ray soil moisture sensors (StyX Neutronica) to estimate large-scale topsoil water content at the catchment.</p><p>Even though the soil management and soil properties in the fields of Nučice seem to be nearly homogeneous, we have observed variability in the topsoil moisture pattern. The method for the explanation of the soil water regime was the combination of the connectivity indices and numerical modelling. The soil moisture profiles from the point-scale sensors were processed in a 1-D physically-based soil water model (HYDRUS-1D) to optimize the soil hydraulic parameters. Further, the soil hydraulic parameters were used as input into a 3D spatially-distributed model, MIKE-SHE. The MIKE-SHE simulation has been mainly calibrated with rainfall-runoff observations. Meanwhile, the spatial patterns of the soil moisture were assessed from the simulation for both dry and wet catchment conditions. From the MIKE-SHE simulation, the optimized soil hydraulic parameters have improved the estimation of soil moisture dynamics and runoff generation. Also, the correlation between the observed and simulated soil moisture spatial patterns showed different behaviors during the dry and wet catchment conditions.</p><p>This study has been supported by the Grant Agency of the Czech Technical University in Prague, grant No. SGS20/156/OHK1/3T/11 and the Project SHui which is co-funded by the European Union Project: 773903 and the Chinese MOST.</p>

Using Soil Moisture and Spatial Yield Patterns to Identify Subsurface Flow Pathways

2005 ◽  
Vol 34 (1) ◽  
pp. 274-286 ◽  
Author(s):  
T. J. Gish ◽  
C. L. Walthall ◽  
C. S. T. Daughtry ◽  
K.-J. S. Kung
Keyword(s):  
Soil Moisture ◽  
Subsurface Flow ◽  
Flow Pathways

scholarly journals Use of field and laboratory methods for estimating unsaturated hydraulic properties under different land uses

2015 ◽  
Vol 19 (3) ◽  
pp. 1193-1207 ◽  
Author(s):  
S. Siltecho ◽  
C. Hammecker ◽  
V. Sriboonlue ◽  
C. Clermont-Dauphin ◽  
V. Trelo-ges ◽  
...  
Keyword(s):  
Land Use ◽  
Unsaturated Soil ◽  
Hydraulic Properties ◽  
Rubber Tree ◽  
Measurement Methods ◽  
Soil Parameters ◽  
Forest Site ◽  
Land Uses ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic

Abstract. Adequate water management is required to improve the efficiency and sustainability of agricultural systems when water is scarce or over-abundant, especially in the case of land use changes. In order to quantify, to predict and eventually to control water and solute transport into soil, soil hydraulic properties need to be determined precisely. As their determination is often tedious, expensive and time-consuming, many alternative field and laboratory techniques are now available. The aim of this study was to determine unsaturated soil hydraulic properties under different land uses and to compare the results obtained with different measurement methods (Beerkan, disc infiltrometer, evaporation, pedotransfer function). The study has been realized on a tropical sandy soil in a mini-watershed in northeastern Thailand. The experimental plots were positioned in a rubber tree plantation in different positions along a slope, in ruzi grass pasture and in an original forest site. Non-parametric statistics demonstrated that van Genuchten unsaturated soil parameters (Ks, α and n) were significantly different according to the measurement methods employed, whereas the land use was not a significant discriminating factor when all methods were considered together. However, within each method, parameters n and α were statistically different according to the sites. These parameters were used with Hydrus1D for a 1-year simulation and computed pressure head did not show noticeable differences for the various sets of parameters, highlighting the fact that for modeling, any of these measurement methods could be employed. The choice of the measurement method would therefore be motivated by the simplicity, robustness and its low cost.

Simulating the Impact of Land Use Activities on Subsurface Flow Regime Using MODFLOW

2001 ◽  
Author(s):  
Jae-Pil Cho ◽  
Victoria Ann Barone ◽  
Saied Mostaghimi
Keyword(s):  
Land Use ◽  
Flow Regime ◽  
Subsurface Flow ◽  
The Impact

scholarly journals Biological and physical influences on soil <sup>14</sup>CO<sub>2</sub> seasonal dynamics in a temperate hardwood forest

2013 ◽  
Vol 10 (12) ◽  
pp. 7999-8012 ◽  
Author(s):  
C. L. Phillips ◽  
K. J. McFarlane ◽  
D. Risk ◽  
A. R. Desai
Keyword(s):  
Soil Moisture ◽  
Soil Carbon ◽  
Root Respiration ◽  
Late Summer ◽  
Co2 Production ◽  
Forest Site ◽  
Surprising Result ◽  
Sampling Campaign ◽  
Microbial Turnover ◽  
High Frequency Sampling

Abstract. While radiocarbon (14C) abundances in standing stocks of soil carbon have been used to evaluate rates of soil carbon turnover on timescales of several years to centuries, soil-respired 14CO2 measurements are an important tool for identifying more immediate responses to disturbance and climate change. Soil Δ14CO2 data, however, are often temporally sparse and could be interpreted better with more context for typical seasonal ranges and trends. We report on a semi-high-frequency sampling campaign to distinguish physical and biological drivers of soil Δ14CO2 at a temperate forest site in northern Wisconsin, USA. We sampled 14CO2 profiles every three weeks during snow-free months through 2012 in three intact plots and one trenched plot that excluded roots. Respired Δ14CO2 declined through the summer in intact plots, shifting from an older C composition that contained more bomb 14C to a younger composition more closely resembling present 14C levels in the atmosphere. In the trenched plot, respired Δ14CO2 was variable but remained comparatively higher than in intact plots, reflecting older bomb-enriched 14C sources. Although respired Δ14CO2 from intact plots correlated with soil moisture, related analyses did not support a clear cause-and-effect relationship with moisture. The initial decrease in Δ14CO2 from spring to midsummer could be explained by increases in 14C-deplete root respiration; however, Δ14CO2 continued to decline in late summer after root activity decreased. We also investigated whether soil moisture impacted vertical partitioning of CO2 production, but found this had little effect on respired Δ14CO2 because CO2 contained modern bomb C at depth, even in the trenched plot. This surprising result contrasted with decades to centuries-old pre-bomb CO2 produced in lab incubations of the same soils. Our results suggest that root-derived C and other recent C sources had dominant impacts on respired Δ14CO2 in situ, even at depth. We propose that Δ14CO2 may have declined through late summer in intact plots because of continued microbial turnover of root-derived C, following declines in root respiration. Our results agree with other studies showing declines in the 14C content of soil respiration over the growing season, and suggest inputs of new photosynthates through roots are an important driver.

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