Temporal variability of soil water content in a semiarid hillslope across time scales: Effect of soil surface condition

2015 ◽  
Vol 112 ◽  
pp. 64-74 ◽  
Author(s):  
Shai Sela ◽  
Tal Svoray ◽  
Shmuel Assouline
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Time Scales ◽  
Temporal Variability ◽  
Surface Condition ◽  
Soil Surface

scholarly journals Temporal variability of soil water content under different surface conditions in the semiarid region of the Pernambuco state

2010 ◽  
Vol 34 (5) ◽  
pp. 1733-1741 ◽  
Author(s):  
Thais Emanuelle Monteiro dos Santos ◽  
Demetrius David da Silva ◽  
Abelardo Antônio de Assunção Montenegro
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Surface Condition ◽  
Soil Surface ◽  
Bare Soil ◽  
Semiarid Region ◽  
Surface Conditions ◽  
Content Variation ◽  
Contour Lines

Rainfall in the semiarid region of Pernambuco is characterized by irregular distribution in time and space, which significantly hinders the rainfed agriculture in the region. This work aims to evaluate the temporal profile of soil moisture in the semiarid region of the Pernambuco State (Brazil) and the effect of different soil surface conditions on soil water content variation and the yield of rainfed beans. To monitor soil water content, five plots 4.5 m wide by 11 m long were installed in a Yellow Argisol (Ultisol). The following treatments were adopted in the experimental plots: natural vegetation, bean intercropped with cactus, beans planted down the slope, beans planted along contour lines with mulch and rock barriers, and bare soil. In each plot, eight PVC access tubes were installed for monitoring the soil water content profile at depths of 0.20 and 0.40 m using a neutron probe device. The surface condition significantly influenced the soil water content variation, both in the dry and rainy seasons. The use of mulch, associated with rock barriers, provided higher soil water content levels than the other treatments and increased the rainfed beans production.

Using soil surface gray level to determine surface soil water content

2010 ◽  
Vol 53 (10) ◽  
pp. 1527-1532 ◽  
Author(s):  
YuanJun Zhu ◽  
YunQiang Wang ◽  
MingAn Shao
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Surface Soil ◽  
Soil Surface ◽  
Gray Level

scholarly journals Field spatial and temporal patterns of soil water content and bulk density changes

2006 ◽  
Vol 63 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Luís Carlos Timm ◽  
Luiz Fernando Pires ◽  
Renato Roveratti ◽  
Robson Clayton Jacques Arthur ◽  
Klaus Reichardt ◽  
...  
Keyword(s):  
Water Content ◽  
Bulk Density ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Surface ◽  
Temporal Patterns ◽  
Temporal Changes ◽  
Spatial And Temporal Patterns ◽  
Wetting And Drying ◽  
Wetting And Drying Cycles

Soil water content (theta) and bulk density (rhos) greatly influence important soil and plant processes, such as water movement, soil compaction, soil aeration, and plant root system development. Spatial and temporal variability of theta and rhos during different periods of the year and different phases of crops are of fundamental interest. This work involves the characterization of spatial and temporal patterns of theta and rhos during different climatic periods of year, aiming to verify whether there are significant temporal changes in rhos at the soil surface layer when submitted to wetting and drying cycles. The field experiment was carried out in a coffee plantation, Rhodic Kandiudalf soil, clayey texture. Using a neutron/gamma surface probe, theta and rhos were measured meter by meter along a 200 m spatial transect, along an interrow contour line. During the wet period there was no difference of spatial patterns of theta while during the dry period differences were observed, and can be associated to precipitation events. It was also observed that there are rhos temporal changes at the soil surface along the studied period as a consequence of the in situ wetting and drying cycles.

Modelling leaching and recharge in a bare transitional red-brown earth ponded with low salinity water in summer

1994 ◽  
Vol 34 (7) ◽  
pp. 1085 ◽  
Author(s):  
L Cai ◽  
SA Prathapar ◽  
HG Beecher
Keyword(s):  
Hydraulic Conductivity ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Profile ◽  
Soil Surface ◽  
Saturated Hydraulic Conductivity ◽  
Rate Dependent ◽  
Water And Salt Movement ◽  
Winter Fallow

A modelling study was conducted to evaluate water and salt movement within a transitional red-brown earth with saline B horizon soil when such waters are used for ponding in summer. The model was calibrated using previously published experimental data. The calibrated model was used to evaluate the effect of depth to watertable, saturated hydraulic conductivity, and ponding water salinity on infiltration, water and salt movement within the soil profile, and recharge. The study showed that when initial soil water content and the saturated hydraulic conductivity (Ks) are low, infiltrating water will be stored within the soil profile even in the absence of a shallow watertable. Once the soil water content is high, however, recharge will be significant in winter, even if there is no net infiltration at the soil surface. Infiltration rates depend more on Ks than the depth to watertable if it is at, or below, 1.5 m from the soil surface. When Ks is high, recharge under ponding will be higher than that under winter fallow. Subsequent ponding in summer and fallow in winter tend to leach salts from the soil profile, the leaching rate dependent on Ks. During winter fallow, due to net evaporation, salts tend to move upwards and concentrate near the soil surface. In the presence of shallow watertables, leached salts tend to concentrate at, or near, the watertable.

Using satellite data in the Land Surface Model to estimate water availability of arid agricultural region

2020 ◽  
Author(s):  
Eugene Muzylev ◽  
Zoya Startseva ◽  
Elena Volkova ◽  
Eugene Vasilenko
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Availability ◽  
Land Surface ◽  
Land Surface Model ◽  
Soil Surface ◽  
Surface Model ◽  
Heat Regime ◽  
Vegetation Characteristics

<p>The water availability of agricultural arid regions can be assessed at presence using the physical-mathematical model of water and heat exchange between land surface and atmosphere LSM (Land Surface Model) adapted to satellite-derived estimates of meteorological and vegetation characteristics. The LSM is designed to calculate soil water content W, evapotranspiration Ev, vertical heat fluxes and other water and heat regime elements. Soil and vegetation characteristics were used in the LSM as parameters and meteorological characteristics were utilized as input variables.</p><p>The case study was carried out for the territory of the Saratov and Volgograd Trans-Volga region (the left-bank part of the Saratov and Volgograd regions) of 66600 km<sup>2</sup> for the vegetation seasons 2016-2018.</p><p>The satellite measurement data from radiometers AVHRR/NOAA, SEVIRI/Meteosat-10, -11, -8, and MSU-MR/Meteor-M No. 2 in visible and IR ranges were thematic processed to built estimates of vegetation index NDVI, emissivity E, vegetation cover fraction B, leaf index LAI, land surface temperature LST and precipitation.</p><p>LAI and B estimates were obtained using empirical dependencies on NDVI. The adequacy of the LAI and B estimates obtained from all sensor data was verified when comparing the LAI time behavior built for named vegetation seasons. Errors of determining B and LAI were 15 and 20%, respectively.</p><p>Satellite-derived estimates of daily, decadal and monthly precipitation sums for each pixel were obtained using the Multi Threshold Method (MTM) for detecting clouds, identifying its types allocating precipitation zones and determining their maximum intensity. The MTM is based on the developed algorithm of the transition from the assessment of precipitation intensity to the assessment of their daily amounts. Testing of the method was carried out when comparing these amounts with observed at meteorological stations. The probability of satellite-detected precipitation zones corresponded to the actual ones was ~ 80% for all radiometers.</p><p>Based on the MTM, computational algorithm to evaluate the LST was developed and verified on the study region data. Comparison of ground-measured and satellite-derived LST showed that the latter estimates for the overwhelming number of observation turned out to be comparable in accuracy with each other and with the ground-based data.</p><p>Calculations of water and heat regime elements (being the final products of the simulation) were carried out when replacing ground-based estimates of precipitation, LST, LAI and B in the LSM by satellite-derived ones at each time step in all nodes of the computational grid. The efficiency of such replacement procedures was confirmed by comparing measured and calculated values of W and Ev (the difference between them didn’t exceed 15% for W and 25% for Ev).</p><p>The possibility of using soil surface moisture estimates obtained from all-weather measurements by the scatterometer ASCAT/MetOp in the microwave range when simulating soil water content was also revealed. These estimates may use to set initial conditions for the vertical soil water transfer equation, as well as for calculating evaporation from the soil surface and the subsequent formation of the upper boundary condition for this equation.</p><p>As a summary, the described approach can be considered as a method for assessing the water availability for agricultural arid region.</p>

Fractal Description of the Spatial and Temporal Variability of Soil Water Content Across an Agricultural Field

Soil Science ◽  
2012 ◽  
Vol 177 (2) ◽  
pp. 131-138 ◽  
Author(s):  
Eva Vidal-Vázquez ◽  
Jorge Paz-Ferreiro ◽  
Sidney Vieira ◽  
George Topp ◽  
José Miranda ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Temporal Variability ◽  
Spatial And Temporal Variability ◽  
Agricultural Field ◽  
Fractal Description

Analysis of Water Budgets in Semi-Arid Lands from Soil Water Records

1995 ◽  
Vol 31 (2) ◽  
pp. 131-150 ◽  
Author(s):  
C. J. Pilbeam ◽  
C. C. Daamen ◽  
L. P. Simmonds
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Surface ◽  
Total Evaporation ◽  
Growing Seasons ◽  
Neutron Probe ◽  
Unsaturated Hydraulic Conductivity ◽  
Probe Measurements

SUMMARYFour components of the water budget for a growing season, namely storage, drainage, transpiration and direct evaporation from the soil surface, were estimated using a suite of techniques. The only data requirements were rainfall, neutron probe measurements of soil water content and microlysimeter measurements of evaporation from the soil. Data from four growing seasons at Kiboko, Kenya between 1990 and 1992 were used to provide examples of the estimations. Drainage was significant (about 10% of rainfall) in one season only; in the other seasons, total evaporation comprised at least 95% of the seasonal rainfall.Drainage was determined using a relationship between unsaturated hydraulic conductivity and soil water content that was determined during the early part of the rainy season when water was penetrating to depth. This analysis made it possible to identify a critical water content at the base of the soil profile, above which there would be significant drainage. However, there are large errors associated with estimation of drainage if significant drainage occurs.Estimates of direct evaporation from the soil surface were used as the basis of distinguishing transpiration from total evaporation. Microlysimetry was used to develop a model of evaporation from these sandy soils, which was based on the assumption that the evaporation from the soil surface following heavy rainfall is a unique function of time from rainfall, and little influenced by the presence of a sparse crop. This method showed that direct evaporation from the soil accounted for between 70 and 85% of total evaporation in seasons when total evaporation estimates ranged from 150 to 325 mm.

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