scholarly journals Water Balance and Soil Moisture Deficit of Different Vegetation Units under Semiarid Conditions in the Andes of Southern Ecuador

Climate ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 30 ◽  
Author(s):  
Andreas Fries ◽  
Karen Silva ◽  
Franz Pucha-Cofrep ◽  
Fernando Oñate-Valdivieso ◽  
Pablo Ochoa-Cueva
Keyword(s):  
Land Use ◽  
Soil Moisture ◽  
Land Use Changes ◽  
Soil Samples ◽  
Soil Moisture Deficit ◽  
Climate Conditions ◽  
The Andes ◽  
Moisture Deficit ◽  
Southern Ecuador ◽  
Semiarid Conditions

Water availability in semiarid regions is endangered, which is not only due to changing climate conditions, but also to anthropogenic land use changes. The present study analyzed the annual and monthly water balance (WBc) and the soil moisture deficit (Ds) for different vegetation units under semiarid conditions in the Andes of southern Ecuador, based on limited meteorological station data and field measurements (soil samples). To calculate crop evapotranspiration (ETc) the Blaney–Criddle method was applied, and the specific crop factor (Kc) included, because only temperature (T) and precipitation (P) data were available. By means of the soil samples the water retention capacity (RC) of the different soil types present in the study area were estimated, which, in combination with WBc, provided reliable results respective to water surpluses or deficits for the different vegetation units. The results indicated highest Ds for cultivated areas, particularly for corn and sugarcane plantations, where annual deficits up to −1377.5 mm ha−1 and monthly deficits up to −181.1 mm ha−1 were calculated. Natural vegetation cover (scrubland, forest and paramo), especially at higher elevations, did not show any deficit throughout the year (annual surpluses up to 1279.6 mm ha−1; monthly surpluses up to 280.1 mm ha−1). Hence, it could be concluded that the prevailing climate conditions in semiarid regions cannot provide the necessary water for agricultural practices, for which reason irrigation is required. The necessary water can be supplied by areas coved by natural vegetation, but these areas are endangered due to population growth and the associated land use changes.

Ozone and Soil Moisture Deficit Effects on Nitrogen Metabolism of Soybean 1

Crop Science ◽  
1987 ◽  
Vol 27 (6) ◽  
pp. 1177-1184 ◽  
Author(s):  
R. B. Flagler ◽  
R. P. Patterson ◽  
A. S. Heagle ◽  
W. W. Heck
Keyword(s):  
Soil Moisture ◽  
Nitrogen Metabolism ◽  
Soil Moisture Deficit ◽  
Moisture Deficit

scholarly journals Impacts of oak deforestation and rainfed cultivation on soil redistribution processes across hillslopes using 137Cs techniques

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Shamsollah Ayoubi ◽  
Nafiseh Sadeghi ◽  
Farideh Abbaszadeh Afshar ◽  
Mohammad Reza Abdi ◽  
Mojtaba Zeraatpisheh ◽  
...  
Keyword(s):  
Land Use ◽  
Magnetic Susceptibility ◽  
Soil Erosion ◽  
Erosion Rate ◽  
Land Use Changes ◽  
Soil Samples ◽  
Natural Forest ◽  
Oak Forests ◽  
Erosion Rates ◽  
Rainfed Farming

Abstract Background As one of the main components of land-use change, deforestation is considered the greatest threat to global environmental diversity with possible irreversible environmental consequences. Specifically, one example could be the impacts of land-use changes from oak forests into agricultural ecosystems, which may have detrimental impacts on soil mobilization across hillslopes. However, to date, scarce studies are assessing these impacts at different slope positions and soil depths, shedding light on key geomorphological processes. Methods In this research, the Caesium-137 (137Cs) technique was applied to evaluate soil redistribution and soil erosion rates due to the effects of these above-mentioned land-use changes. To achieve this goal, we select a representative area in the Lordegan district, central Iran. 137Cs depth distribution profiles were established in four different hillslope positions after converting natural oak forests to rainfed farming. In each hillslope, soil samples from three depths (0–10, 10–20, and 20–50 cm) and in four different slope positions (summit, shoulder, backslope, and footslope) were taken in three transects of about 20 m away from each other. The activity of 137Cs was determined in all the soil samples (72 soil samples) by a gamma spectrometer. In addition, some physicochemical properties and the magnetic susceptibility (MS) of soil samples were measured. Results Erosion rates reached 51.1 t·ha− 1·yr− 1 in rainfed farming, whereas in the natural forest, the erosion rate was 9.3 t·ha− 1·yr− 1. Magnetic susceptibility was considerably lower in the cultivated land (χhf = 43.5 × 10− 8 m3·kg− 1) than in the natural forest (χhf = 55.1 × 10− 8 m3·kg− 1). The lower soil erosion rate in the natural forest land indicated significantly higher MS in all landform positions except at the summit one, compared to that in the rainfed farming land. The shoulder and summit positions were the most erodible hillslope positions in the natural forest and rainfed farming, respectively. Conclusions We concluded that land-use change and hillslope positions played a key role in eroding the surface soils in this area. Moreover, land management can influence soil erosion intensity and may both mitigate and amplify soil loss.

scholarly journals The United Kingdom Meteorological Office rainfall and evaporation calculation system: MORECS version 2.0-an overview

1997 ◽  
Vol 1 (2) ◽  
pp. 227-239 ◽  
Author(s):  
M. N. Hough ◽  
R. J. A. Jones
Keyword(s):  
Land Use ◽  
Climatic Conditions ◽  
Soil Moisture Deficit ◽  
Water Capacity ◽  
The United Kingdom ◽  
Moisture Deficit ◽  
Available Water Capacity ◽  
Version 2.0 ◽  
Calculation System ◽  
New System

Abstract. The operational system known as MORECS which provides estimates of evaporation, soil moisture deficit and effective precipitation under British climatic conditions has been revised as version 2.0. An overview of the new system is described with emphasis on the new additions. The major changes from the older version (Thomson, Barrie and Ayles, 1981) include the introduction of the crop oil-seed rape, a revised treatment of soils and available water capacity and a land use data base which is representative of the 1990s.

scholarly journals Using Plant Temperature to Evaluate the Response of Stomatal Conductance to Soil Moisture Deficit

Forests ◽  
2015 ◽  
Vol 6 (12) ◽  
pp. 3748-3762 ◽  
Author(s):  
Ming-Han Yu ◽  
Guo-Dong Ding ◽  
Guang-Lei Gao ◽  
Yuan-Yuan Zhao ◽  
Lei Yan ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Stomatal Conductance ◽  
Soil Moisture Deficit ◽  
Moisture Deficit

Modelling the Hydrologic Regime of Arid Inland Wetlands: Non-linear Relationship Between Root-uptakes of Water and Underground Water Table

2021 ◽  
Author(s):  
Lin Li ◽  
Hu Liu ◽  
Yang Yu ◽  
Wenzhi Zhao
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Soil Moisture ◽  
Water Table ◽  
Land Use Changes ◽  
Northwestern China ◽  
Wetland Ecosystem ◽  
Soil Moisture Dynamics ◽  
Inland Wetlands ◽  
Moisture Dynamics

<p><strong>Abstract: </strong>Wetlands remaining in the arid inland river landscapes of northwestern China suffer degradation and their resilience and ability to continue functioning under hydrologic and land use changes resulting from climate change may be significantly inhibited. Information on the desert-oasis wetlands, however, is sparse and knowledge of how ecological functioning and resilience may change under climate change and water-resource management is still lacking. Research in oasis wetland areas of the Northwestern China identified linkages between subsurface flow, plant transpiration, and water levels. In this study, we present an ecohydrological analysis of the energy and water balance in the wetland ecosystem. A process-based stochastic soil moisture model developed for groundwater-dependent ecosystems was employed to modelling the interactions between rainfall, water table fluctuations, soil moisture dynamics, and vegetation, and to investigate the ecohydrology of arid inland wetlands system. Field measured groundwater levels, vertical soil moisture profiles, soil water potentials, and root biomass allocation and transpiration of pioneer species in the wetlands were used to calibrate and validate the stochastic model. The parameterized model was then running to simulate the probability distributions of soil moisture and root water uptake, and quantitative descript the vegetation–water table–soil moisture interplay in the hypothesized scenarios of future. Our analysis suggested the increasing rates of water extraction and regulation of hydrologic processes, coupled with destruction of natural vegetation, and climate change, are jeopardizing the future persistence of wetlands and the ecological and socio-economic functions they support. To understand how climate change will impact on the ecohydrological functioning of wetlands, both hydrological and land use changes need to be considered in future works.</p><p><strong>Keywords: </strong>Wetland ecosystem, groundwater, soil moisture dynamics, water balances, Heihe River Basin</p>

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