SIMULATION OF SOIL WATER DYNAMICS IN A CARAGANA INTERMEDIA WOODLAND IN HUANGFUCHUAN WATERSHED: RELATIONSHIPS AMONG SLOPE, ASPECT, PLANT DENSITY AND SOIL WATER CONTENT

Fortnightly soil water content measurements to a depth of 2.1 m under 4 cocksfoot cultivars, 2 phalaris cultivars, 2 lucerne cultivars and 1 Lotus corniculatus cultivar were used to compare soil profile drying and to define seasonal patterns of plant water use of the species over a 3-year period, on a duplex soil. Cultivars were also selected, within species groups, for varying seasonal growth patterns to assess this influence on soil water dynamics and growth. Over the 3-year period, treatments with the highest and lowest measures of profile soil water content were used to derive and compare values of maximum plant extractable water. Plots were maintained for a further 3 years, after which soil water content measurements in autumn were used to assess long-term effects of the treatments. The effect of seasonal growth patterns within a species was negligible; however, there were significant differences between species. Twenty-one months after pasture establishment, lucerne alone had a drying effect at 2.0 m depth and subsequently it consistently showed profiles with the lowest soil water content. Maximum plant extractable water was greatest for lucerne (230 mm), followed by phalaris (210 mm), Lotus corniculatus (200 mm) and cocksfoot (170 mm). Profiles with the lowest soil water content were associated with greater herbage growth and greater depths of water extraction. The soil water deficits developed by the treatments in autumn of the fourth year were similar to those measured in autumn of the seventh year, implying that a species-dependant equilibrium had been reached. Long-term rainfall data is used to calculate the probabilities of recharge occurring when rainfall exceeds maximum potential deficits for the different pasture species.

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Soil water response to rainfall in a dune-interdune landscape in Horqin Sand Land, northern China

Soil and Water Research ◽

10.17221/142/2018-swr ◽

2019 ◽

Vol 14 (No. 4) ◽

pp. 229-239 ◽

Cited By ~ 1

Author(s):

Xueya Zhou ◽

Dexin Guan ◽

Jiabing Wu ◽

Fenghui Yuan ◽

Anzhi Wang ◽

...

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Northern China ◽

Water Dynamics ◽

Soil Water Dynamics ◽

Water Recharge ◽

Sand Land ◽

Horqin Sand Land ◽

The Relationship

Soil water dynamic is considered an important process for water resource and plantation management in Horqin Sand Land, northern China. In this study, soil water content simulated by the SWMS-2D model was used to systematically analyse soil water dynamics and explore the relationship between soil water and rainfall among micro-landforms (i.e., top, upslope, midslope, toeslope, and bottomland) and 0–200 cm soil depths during the growing season of 2013 and 2015. The results showed that soil water dynamics in 0–20 cm depths were closely linked to rainfall patterns, whereas soil water content in 20–80 cm depths illustrated a slight decline in addition to fluctuations caused by rainfall. At the top position, the soil water content in different ranges of depths (20–40 and 80–200 cm) was near the wilting point, and hence some branches, and even entire plants exhibited diebacks. At the upslope or midslope positions, the soil water content in 20–80 or 80–200 cm depths was higher than at the top position. Soil water content was higher at the toeslope and bottomland positions than at other micro-landforms, and deep caliche layers had a positive feedback effect on shrub establishment. Soil water recharge by rainfall was closely related to rainfall intensity and micro-landforms. Only rainfalls > 20 mm significantly increased water content in > 40 cm soil depths, but deeper water recharge occurred at the toeslope position. A linear equation was fitted to the relationship between soil water and antecedent rainfall, and the slopes and R<sup>2</sup> of the equations were different among micro-landforms and soil depths. The linear equations generally fitted well in 0–20 and 20–40 cm depths at the top, upslope, midslope, and toeslope positions (R<sup>2</sup> value of about 0.60), with soil water in 0–20 cm depths showing greater responses to rainfall (average slope of 0.189). In 20–40 cm depths, the response was larger at the toeslope position, with a slope of 0.137. In 40–80 cm depths, a good linear fit with a slope of 0.041 was only recorded at the toeslope position. This study provides a soil water basis for ecological restoration in similar regions.

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Estimating field-scale soil water dynamics at a heterogeneous site using multi-channel GPR

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-9-8027-2012 ◽

2012 ◽

Vol 9 (7) ◽

pp. 8027-8062 ◽

Cited By ~ 1

Author(s):

X. Pan ◽

J. Zhang ◽

P. Huang ◽

K. Roth

Keyword(s):

Time Series ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Water Dynamics ◽

Water Volume ◽

Heavy Rainfall Event ◽

Field Scale ◽

Soil Water Dynamics ◽

Layer Boundary

Abstract. We explore the feasibility to quantify the field-scale soil water dynamics through time series of GPR (ground-penetrating radar) measurements. They bridge the gap between accurate and well-established point measurements and the field-scale where soil hydrology issues are addressed. Working on a 40 m × 50 m area in a heterogeneous agricultural field, we obtain a time series of radargrams after a heavy rainfall event. On the one hand, these yield a three-dimensional representation of the subsurface architecture, in particular of the layer boundary that originates from paleo-sand dunes and of a number of clay inclusions in an otherwise rather uniform sand. On the other hand, the total soil water volume between the surface and the layer boundary is obtained. We assess the precision and the accuracy of these quantities and conclude that the method is sensitive enough to capture the spatial structure of the changing soil water content. While the sensitivity of the method still needs to be improved, it already produced useful information to understand the observed patterns in crop height and it yielded insight into the dynamics of soil water content at this site including the effect of evaporation.

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Assessment of Drought in Agricultural Regions of Slovakia Using Soil Water Dynamics Simulation

Agriculture (Pol nohospodárstvo) ◽

10.2478/agri-2013-0007 ◽

2013 ◽

Vol 59 (2) ◽

pp. 74-87 ◽

Cited By ~ 1

Author(s):

Jozef Takáč

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Water Dynamics ◽

Extreme Drought ◽

Dynamics Simulation ◽

Drought Severity ◽

Soil Water Dynamics ◽

Agricultural Regions ◽

Drought Occurrence

Assessment of agronomic drought occurrence and severity in agricultural regions of Slovakia is presented in the paper. Drought severity assessment is based on the soil water dynamics simulation by agroecological model Daisy. Daily meteorological data from the years 1961-2012 from 31 localities were used in simulations. Criteria for the drought occurrence were 1) available soil water content below 50% of available water capacity, 2) soil water content below long-term average soil water content and 3) duration of continuous drought for fifteen or more days. Standardized index of daily available soil water content was used for drought severity classification. According to the index the drought is categorized into four degrees of severity from mild to extreme drought. Cumulative sum of available soil water index was used to drought quantification throughout its duration. Normal climate period 1961- 1990 was chosen as reference period to enable historical comparison of drought severity as well as climate change impacts. Extreme drought of the largest spatial extent was identified in 1990. Extreme drought occurred regionally in the southwest Slovakia in 1978 and in the southeast Slovakia in 1986, respectively.

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Comparison between Soil Water Dynamics Simulated by the Isothermal and Non-Isothermal Models

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.864-867.2298 ◽

2013 ◽

Vol 864-867 ◽

pp. 2298-2301

Author(s):

Jiang Bo Han ◽

Zhi Fang Zhou

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Water Table ◽

Water Dynamics ◽

Soil Water Dynamics ◽

Isothermal Model ◽

Dynamic Variations ◽

Soil Temperatures ◽

One Year

To obtain a better understanding of the role of non-isothermal flow in the unsaturated zone in the presence of the water table, the isothermal and non-isothermal models driven by the observed atmospheric data were used to reproduce soil moisture dynamics observed in the lysimeter with a 100-cm water table level over one year period. Results from the simulations indicated that although the isothermal and non-isothermal models both captured the general trend of soil water content dynamics during one year period, simulated values by the isothermal model presented less dynamic variations, which overestimated the soil water content during the rainy season and underestimated it during other periods. On the other hand, the non-isothermal model not only reproduced well the seasonal variations of soil temperatures but also reproduced more reasonably soil water dynamics in the whole profile and during the whole simulation period.

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Soil-water dynamics and unsaturated storage during snowmelt following wildfire

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-9-441-2012 ◽

2012 ◽

Vol 9 (1) ◽

pp. 441-483

Author(s):

B. A. Ebel ◽

E. S. Hinckley ◽

D. A. Martin

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Water Storage ◽

Field Capacity ◽

Water Dynamics ◽

Soil Water Storage ◽

Soil Water Dynamics ◽

Near Surface ◽

Snowmelt Period

Abstract. Many forested watersheds with a substantial fraction of precipitation delivered as snow have the potential for landscape disturbance by wildfire. Little is known about the immediate effects of wildfire on snowmelt and near-surface hydrologic responses, including soil-water storage. Montane systems at the rain-snow transition have soil-water dynamics that are further complicated during the snowmelt period by strong aspect controls on snowmelt and soil thawing. Here we present data and analysis from field measurements of snow hydrology and subsurface hydrologic and temperature responses during the first winter and spring after the September 2010 Fourmile Canyon Fire in Colorado, USA. Our observations of soil-water content and soil temperature show sharp contrasts in hydrologic and thermal conditions between north- and south-facing slopes. South-facing burned soils were ~1–2 °C warmer on average than north-facing burned soils and ~1.5 °C warmer than south-facing unburned soils, which affected soil thawing during the snowmelt period. Soil-water dynamics also differed by aspect: in response to soil thawing, soil-water content increased approximately one month earlier on south-facing burned slopes than on north-facing burned slopes. While aspect and wildfire affect soil-water dynamics during snowmelt, soil-water storage at the end of the snowmelt period reached the value at field capacity for each plot, suggesting that post-snowmelt unsaturated storage was not substantially influenced by aspect in wildfire-affected areas. Our data and analysis indicate that snowmelt-driven groundwater recharge may be larger in wildfire-impacted areas, especially on south-facing slopes, because of earlier soil thaw and longer durations of soil-water contents above field capacity in those areas.

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Soil-water dynamics and unsaturated storage during snowmelt following wildfire

Hydrology and Earth System Sciences ◽

10.5194/hess-16-1401-2012 ◽

2012 ◽

Vol 16 (5) ◽

pp. 1401-1417 ◽

Cited By ~ 17

Author(s):

B. A. Ebel ◽

E. S. Hinckley ◽

D. A. Martin

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Water Storage ◽

Field Capacity ◽

Water Dynamics ◽

Soil Water Storage ◽

Soil Water Dynamics ◽

Near Surface ◽

Snowmelt Period

Abstract. Many forested watersheds with a substantial fraction of precipitation delivered as snow have the potential for landscape disturbance by wildfire. Little is known about the immediate effects of wildfire on snowmelt and near-surface hydrologic responses, including soil-water storage. Montane systems at the rain-snow transition have soil-water dynamics that are further complicated during the snowmelt period by strong aspect controls on snowmelt and soil thawing. Here we present data from field measurements of snow hydrology and subsurface hydrologic and temperature responses during the first winter and spring after the September 2010 Fourmile Canyon Fire in Colorado, USA. Our observations of soil-water content and soil temperature show sharp contrasts in hydrologic and thermal conditions between north- and south-facing slopes. South-facing burned soils were ∼1–2 °C warmer on average than north-facing burned soils and ∼1.5 °C warmer than south-facing unburned soils, which affected soil thawing during the snowmelt period. Soil-water dynamics also differed by aspect: in response to soil thawing, soil-water content increased approximately one month earlier on south-facing burned slopes than on north-facing burned slopes. While aspect and wildfire affect soil-water dynamics during snowmelt, soil-water storage at the end of the snowmelt period reached the value at field capacity for each plot, suggesting that post-snowmelt unsaturated storage was not substantially influenced by aspect in wildfire-affected areas. Our data and analysis indicate that the amount of snowmelt-driven groundwater recharge may be larger in wildfire-impacted areas, especially on south-facing slopes, because of earlier soil thaw and longer durations of soil-water contents above field capacity in those areas.

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Estimating field-scale soil water dynamics at a heterogeneous site using multi-channel GPR

Hydrology and Earth System Sciences ◽

10.5194/hess-16-4361-2012 ◽

2012 ◽

Vol 16 (11) ◽

pp. 4361-4372 ◽

Cited By ~ 13

Author(s):

X. Pan ◽

J. Zhang ◽

P. Huang ◽

K. Roth

Keyword(s):

Time Series ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Three Dimensional ◽

Water Dynamics ◽

Water Volume ◽

Heavy Rainfall Event ◽

Field Scale ◽

Soil Water Dynamics

Abstract. We explore the feasibility to quantify the field-scale soil water dynamics through time series of GPR (ground-penetrating radar) measurements, which bridge the gap between point measurements and field measurements. Working on a 40 m × 50 m area in a heterogeneous agricultural field, we obtain a time series of radargrams after a heavy rainfall event. The data are analysed to simultaneously yield (i) a three-dimensional representation of the subsurface architecture and (ii) the total soil water volume between the surface and a reflection boundary associated with the presence of paleo sand dunes or clay inclusions in a rather uniform sand matrix. We assess the precision and the accuracy of these quantities and conclude that the method is sensitive enough to capture the spatial structure of the changing soil water content in a three-dimensional heterogeneous soil during a short-duration infiltration event. While the sensitivity of the method needs to be improved, it already produced useful information to understand the observed patterns in crop height and it yielded insight into the dynamics of soil water content at this site including the effect of evaporation.

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Analysis of soil water dynamics in an agroforestry system based on detailed soil water records from time-domain reflectometry

Hydrology and Earth System Sciences ◽

10.5194/hess-3-517-1999 ◽

1999 ◽

Vol 3 (4) ◽

pp. 517-527 ◽

Cited By ~ 5

Author(s):

N. A. Jackson ◽

J. C. Wallace

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Time Domain ◽

Agroforestry System ◽

Time Domain Reflectometry ◽

Water Dynamics ◽

Spatial And Temporal Variation ◽

Soil Water Dynamics ◽

Tree Canopies

Abstract. Time domain reflectometry [TDR] was used to investigate the spatial and temporal variation in surface soil water dynamics under a number of types of vegetation, including both trees and crops grown in isolation, and grown together as an agroforestry system. The installation and operation of this technique are presented, and discussed in terms of its suitability to monitor rapid fluctuations in soil-water content in a spatially heterogeneous system such as that described in this experiment. The relatively small sampling volume of each of the TDR waveguides permitted discrete measurements to be made of soil water content (θv). In the tree-only and tree+crop treatments, this revealed considerable variation in θv resulting from spatial redistribution of rainfall under the tree canopies, with a significant input to soil close to the base of the trees being made by stemflow, i.e. water intercepted by the tree canopy and channelled down the stem. Over the experimental period (one rainy season) the TDR data suggested that net recharge to the soil profile in the sole crop system was 53 mm, almost 75% more than occurred in either of the two treatments containing trees, reflecting greater rainfall interception by the tree canopies.

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The critical soil water content and its relation to soil water dynamics

Scientia Agricola ◽

10.1590/s0103-90161997000300009 ◽

1997 ◽

Vol 54 (spe) ◽

pp. 45-50 ◽

Cited By ~ 3

Author(s):

Q. de Jong Van Uer

Keyword(s):

Water Potential ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Transpiration Rate ◽

Hydraulic Properties ◽

Root Density ◽

Water Dynamics ◽

Plant Roots ◽

Soil Water Dynamics

Using an edaphic model that describes the extraction of soil water by plant roots, the occurrence of depletion zones dose to plant roots is demonstrated. These depletion zones affect the root water potential that is needed to maintain a certain transpiration rate. The results show how the critical soil water content depends on soil's hydraulic properties, transpiration rate and root density.

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