scholarly journals Simulated climate change affects how biocrusts modulate infiltration and desiccation dynamics

2017 ◽  
Author(s):  
Angela Lafuente ◽  
Miguel Berdugo ◽  
Mónica Ladrón de Guevara ◽  
Beatriz Gozalo ◽  
Fernando T. Maestre
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Soil Water ◽  
Potential Evapotranspiration ◽  
Soil Surface ◽  
Maximum Temperature ◽  
Rainfall Events ◽  
Exponential Behaviour ◽  
Drying Rates ◽  
Gains And Losses

AbstractSoil surface communities dominated by mosses, lichens and cyanobacteria (biocrusts) cover most of the soil surface between vegetation patches in drylands worldwide, and are known to affect soil wetting and drying after rainfall events. While ongoing climate change is already warming and changing rainfall patterns of drylands in many regions, little is known on how these changes may affect the hydrological behaviour of biocrust-covered soils. We used eight years of continuous soil moisture and rainfall data from a climate change experiment in central Spain to explore how biocrusts modify soil water gains and losses after rainfall events under simulated changes in temperature (2.5ºC warming) and rainfall (33% reduction). Both rainfall amount and biocrust cover increased soil water gains after rainfall events, whereas experimental warming, rainfall intensity and initial soil moisture decreased them. Initial moisture, maximum temperature and biocrust cover, by means of enhancing potential evapotranspiration or soil darkening, increased the drying rates and enhanced the exponential behaviour of the drying events. Meanwhile, the warming treatment reduced the exponential behaviour of these events. The effects of climate change treatments on soil water gains and losses changed through time, with important differences between the first two years of the experiment and after five years since its setup. These effects were mainly driven by the important reductions in biocrust cover and diversity observed under warming. Our results highlight the importance of long term studies to understand soil moisture responses to ongoing climate change in drylands.

scholarly journals Soil Management by Cover Crops in Vineyards for Climate Change Adaptation

Proceedings ◽  
2019 ◽  
Vol 30 (1) ◽  
pp. 26
Author(s):  
Marqués ◽  
Bienes ◽  
Ruiz-Colmenero
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Soil Moisture ◽  
Soil Organic Matter ◽  
Climate Change Adaptation ◽  
Climatic Conditions ◽  
Water Infiltration ◽  
Soil Conditions ◽  
Grass Cover ◽  
Rainfall Events

The wine captures grapes’ variety nature and vinification techniques, but other aspects of soil, climate and terrain are equally important for the terroir expression as a whole. Soil supplies moisture, nitrogen, and minerals. Particularly nitrogen obtained through mineralization of soil organic matter and water uptake are crucial for grape yield, berry sugar, anthocyanin and tannin concentration, hence grape quality and vineyard profitability. Different climatic conditions, which are predicted for the future, can significantly modify this relationship between vines and soils. New climatic conditions under global warming predict higher temperatures, erratic and extreme rainfall events, and drought spells. These circumstances are particularly worrisome for typical thin soils of the Mediterranean environment. This study reports the effect of permanent grass cover in vineyards to maintain or increase soil organic matter and soil moisture. The influence of natural and simulated rainfalls on soils was studied. A comparison between minimum tillage (MT) and permanent grass cover crop (GC) of the temperate grass Brachypodium distachyon was done. Water infiltration, water holding capacity, organic carbon sequestration and protection from extreme events, were considered in a sloping vineyard located in the south of Madrid, Spain. The MT is the most widely used cultivation method in the area. The tradition supports this management practice to capture and preserve water in soils. It creates small depressions that accumulate water and eventually improves water infiltration. This effect was acknowledged in summer after recent MT cultivation; however, it was only short-lived as surface roughness declined after rainfalls. Especially, intense rainfall events left the surface of bare soil sealed. Consequently, the effects depend on the season of the year. In autumn, a rainy season of the year, MT failed to enhance infiltration. On the contrary, B. distachyon acted as a physical barrier, produced more infiltration (22% increase) and fewer particles detachment, due to increased soil structure stability and soil organic matter (50% increase). The GC efficiently protected soil from high-intensity events (more than 2 mm min-1). Besides, soil moisture at 35 cm depth was enhanced with GC (9% more than tillage). On average, soil moisture in GC was not significantly different from MT. These effects of GC on soil conditions created local micro-environmental conditions that can be considered advantageous as a climate change adaptation strategy, because they improved water balance, maintained a sustainable level of soil organic matter, therefore organic nitrogen, all these factors crucial for improving wine quality.

scholarly journals The study of potential evapotranspiration in future periods due to climate change in west of Iran

2018 ◽  
Vol 10 (1) ◽  
pp. 161-177 ◽  
Author(s):  
Ahmad Rajabi ◽  
Zahra Babakhani
Keyword(s):  
Climate Change ◽  
Potential Evapotranspiration ◽  
Circulation Model ◽  
Weather Data ◽  
Maximum Temperature ◽  
Global Circulation Model ◽  
Content Type ◽  
Global Circulation ◽  
Change Effect ◽  
Climate Change Effect

Purpose This study aims to present the climate change effect on potential evapotranspiration (ETP) in future periods. Design/methodology/approach Daily minimum and maximum temperature, solar radiation and precipitation weather parameters have been downscaled by global circulation model (GCM) and Lars-WG outputs. Weather data have been estimated according to the Had-CM3 GCM and by A1B, A2 and B1 scenarios in three periods: 2011-2030, 2045-2046 and 2080-2099. To select the more suitable method for ETP estimation, the Hargreaves-Samani (H-S) method and the Priestly–Taylor (P-T) method have been compared with the Penman-Monteith (P-M) method. Regarding the fact that the H-S method has been in better accordance with the P-M method, ETP in future periods has been estimated by this method for different scenarios. Findings In all five stations, in all three scenarios and in all three periods, ETP will increase. The highest ETP increase will occur in the A1B scenario and then in the A1 scenario. The lowest increase will occur in the B1 scenario. In the 2020 decade, the highest ETP increase in three scenarios will occur in Khorramabad and then Hamedan. Kermanshah, Sanandaj and Ilam stations come at third to fifth place, respectively, with a close increase in amount. In the 2050 decade, ETP increase percentages in all scenarios are close to each other in all the five stations. In the 2080 decade, ETP increase percentages in all scenarios will be close to each other in four stations, namely, Kermanshah, Sanandaj, Khorramabad and Hamedan, and Ilam station will have a higher increase compared with the other four stations. Originality/value Meanwhile, the highest ETP increase will occur in hot months of the year, which are significant with regard to irrigation and water resources.

scholarly journals Ecohydrologic controls on vegetation density and evapotranspiration partitioning across the climatic gradients of the central United States

2008 ◽  
Vol 5 (2) ◽  
pp. 649-700 ◽  
Author(s):  
J. P. Kochendorfer ◽  
J. A. Ramírez
Keyword(s):  
United States ◽  
Soil Moisture ◽  
Water Balance ◽  
Soil Water ◽  
Water Use ◽  
Soil Surface ◽  
Soil Water Balance ◽  
Vegetation Density ◽  
Study Region ◽  
Central United States

Abstract. The soil-water balance and plant water use are investigated over a domain encompassing the central United States using the Statistical-Dynamical Ecohydrology Model (SDEM). The seasonality in the model and its use of the two-component Shuttleworth-Wallace canopy model allow for application of an ecological optimality hypothesis in which vegetation density, in the form of peak green leaf area index (LAI), is maximized, within upper and lower bounds, such that, in a typical season, soil moisture in the latter half of the growing season just reaches the point at which water stress is experienced. Another key feature of the SDEM is that it partitions evapotranspiration into transpiration, evaporation from canopy interception, and evaporation from the soil surface. That partitioning is significant for the soil-water balance because the dynamics of the three processes are very different. The partitioning and the model-determined peak in green LAI are validated based on observations in the literature, as well as through the calculation of water-use efficiencies with modeled transpiration and large-scale estimates of grassland productivity. Modeled-determined LAI are seen to be at least as accurate as the unaltered satellite-based observations on which they are based. Surprising little dependence on climate and vegetation type is found for the percentage of total evapotranspiration that is soil evaporation, with most of the variation across the study region attributable to soil texture and the resultant differences in vegetation density. While empirical evidence suggests that soil evaporation in the forested regions of the most humid part of the study region is somewhat overestimated, model results are in excellent agreement with observations from croplands and grasslands. The implication of model results for water-limited vegetation is that the higher (lower) soil moisture content in wetter (drier) climates is more-or-less completely offset by the greater (lesser) amount of energy available at the soil surface. This contrasts with other modeling studies which show a strong dependence of evapotranspiration partitioning on climate.

scholarly journals Classificação e Análises das Indicações de Mudanças Climáticas no Município de Sobral - Ceará (Classification and Analysis of Indications of Climate Change in the City of Sobral – Ceará)

2012 ◽  
Vol 4 (5) ◽  
pp. 1056
Author(s):  
Raimundo Mainar Medeiros ◽  
Paulo Roberto Megna Francisco ◽  
Alexandra Lima Tavares
Keyword(s):  
Climate Change ◽  
Relative Humidity ◽  
Water Balance ◽  
Potential Evapotranspiration ◽  
Temperature Fluctuations ◽  
Maximum Temperature ◽  
Temperature Variations ◽  
Meteorological Elements ◽  
The City

A partir das séries climatológicas normais de 1931-1960 e 1961-1990 dos elementos meteorológicos realizaram-se os cálculos do balanço hídrico climatológico, a classificação e as análises das indicações de mudanças climáticas no município de Sobral, estado do Ceará, utilizando O programa do BHnorm  elaborado em planilhas eletrônicas no pacote Excel por Sentelhas et al. (1999) e a metodologia de cálculo do Balanço Hídrico Climático de Thornthwaite & Mather (1955) e a classificação de Thornthwaite (1955), com o objetivo de contribuir para a sustentabilidade do homem no campo. Identificou-se que o clima da área de estudo classifica-se como Megatérmico semiárido e o tipo climático passou do tipo dw2w2d’ para dw2Dd’ com reduções da temperatura mínima e com oscilações de -0,1 a -0,8ºC e temperatura máxima com variações de -1,7 à 2,1ºC.  A umidade relativa do ar ocorreu flutuações positivas de 0,3 à 3,4%. A evapotranspiração potencial oscilou em -71,0 mm em relação aos períodos para o mês de outubro. Os índices de umidade; aridez e hídricos demonstraram valores de 28,6%, -23,9% e -47,5%, respectivamente. Observou-se que todas estas variabilidades ocorreram devido aos efeitos causados pelo homem na estrutura da cidade. Palavras-chave: Meteorologia. Balanço Hídrico Climático. Clima.  Classification and Analysis of Indications of Climate Change in the City of Sobral – Ceará  ABSTRACTFrom the series 1931-1960 climatological normal from 1961-1990 and meteorological elements were carried out calculations of the climatic water balance, classification and analysis of the indications of climate change in the city of Sobral, Ceará State, using the program BHnorm prepared in Excel spreadsheets in the package by Sentelhas et al. (1999) and the methodology of calculation of the Climatic Water Balance of Thornthwaite & Mather (1955) and the classification of Thornthwaite (1955), in order to contribute to the sustainability of the man in the field. It was found that the climate of the study area is classified as megathermal semiarid climate and the type has type dw2w2d 'to dw2Dd' with reductions in the minimum temperature fluctuations and from -0.1 to -0.8 º C and maximum temperature variations with 2.1 to -1.7 ° C. The relative humidity was positive fluctuations of 0.3 to 3.4%. The potential evapotranspiration fluctuated -71.0 mm for the periods for the month of October. The contents of moisture, drought and water showed values ​​of 28.6% -23.9% and -47.5%, respectively. It was observed that all these effects occurred due to variability caused by man in the structure of the city.  Keywords: Meteorology. Climatic Water Balance. Climate.

scholarly journals Hydro-climatic and land use/cover changes in Nasia catchment of the White Volta basin in Ghana

2021 ◽  
Author(s):  
Emmanuel Nyadzi ◽  
Enoch Bessah ◽  
Gordana Kranjac-Berisavljevic ◽  
Fulco Ludwig
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Water Resources ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Potential Evapotranspiration ◽  
Sunshine Duration ◽  
Climatic Variables ◽  
Northern Ghana ◽  
Maximum Temperature

AbstractThe Nasia catchment is the reservoir with significant surface water resources in Northern Ghana and home to numerous subsistence farmers engaged in rainfed and dry season irrigation farming. Yet, there is little understanding of the hydro-climatic and land use/cover conditions of this basin. This study investigated trends, relationships and changes in hydro-climatic variables and land use/cover in addition to implications of the observable changes in the Nasia catchment over a period of 50 years. Parameters used for the study were minimum (Tmin) and maximum temperature (Tmax), wind speed (WS), sunshine duration (S), rainfall (R), relative humidity (RH), discharge (D) and potential evapotranspiration (PET) data, 15 years of remotely sensed normalized difference vegetation index (NDVI) data and 30 years of land use/cover image data. Results show that Tmin, Tmax, WS and PET have increased significantly (p < 0.05) over time. RH and S significantly declined. R, D and NDVI have not decreased significantly (p > 0.05). A significant abrupt change in almost all hydro-climatic variables started in the 1980s, a period that coincides with the occurrence of drought events in the region, except WS in 2001, R in 1968 and D in 1975, respectively. Also, D showed a positive significant correlation with RH, R and PET, but an insignificant positive relationship with S. D also showed a negative insignificant correlation with Tmin, Tmax and WS. Areas covered with shrubland and settlement/bare lands have increased to the disadvantage of cropland, forest, grassland and water bodies. It was concluded that climate change impact is quite noticeable in the basin, indicating water scarcity and possibilities of droughts. The analysis performed herein is a vital foundation for further studies to simulate and predict the effect of climate change on the water resources, agriculture and livelihoods in the Nasia catchment.

Prediction of future development of soil water erosion in small agricultural chatchment

2021 ◽  
Author(s):  
Silvia Kohnová ◽  
Zuzana Németová ◽  
Zuzana Sabová
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Soil Erosion ◽  
Soil Water ◽  
Future Development ◽  
Soil Degradation ◽  
Water Erosion ◽  
Land Use Management ◽  
Rainfall Events ◽  
The Future

&lt;p&gt;It is well known that the impact of climate change affects various areas such as hydroclimatical factors which can cause increased occurrence of heavy precipitation events, ice melting, rising temperature or sea-level as a consequence of the global warming. It is assumed that the average surface temperature on Earth has increased by more than 1&amp;#176; Celsius since 1880. Climate change of the Earth has changed naturally over the past 650.000 years as a result of external factors that impact the climate. Despite of this fact, over the last 100 years is global warming strongly accelerated by different kind of human activities. One of those activities represents inappropriate land use management which is directly connected with soil degradation and soil erosion as the major threat of global soil degradation. The study presents the assessment of the future development of soil water erosion processes in one small agricultural catchment located in the Slovak Republic. The calculations were done based on the long-term simulation using the event and physically-based soil erosion model and one-hour rainfall events. The model used was calibrated and validated in the previous studies. The period time analysed covers 80 years, i.e., from 2020 until 2100. From the period the years where the most intensive rainfall events have occurred were chosen. The rainfall events were determined by climate CLM model. In order to compare the suitability of land-use management, three scenarios were created. They include three different types of land cover, i.e., agricultural crops (wheat and corn) and grassland. The modelled results show development of soil erosion in the future period up to 2100 together with the comparison of land use management in the area under research. The study predicts the future development of soil water erosion where the short term extreme rainfall events play key element as a crucial factor in the soil erosion assessment processes.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

EFFECTS OF SOIL WATER MOVEMENT ON ACTUAL EVAPOTRANSPIRATION ESTIMATED FROM THE SOIL MOISTURE BUDGET

1970 ◽  
Vol 50 (3) ◽  
pp. 409-417 ◽  
Author(s):  
WAYNE R. ROUSE
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Movement ◽  
Potential Evapotranspiration ◽  
Sandy Loam ◽  
Spatial Variations ◽  
Actual Evapotranspiration ◽  
Moisture Budget ◽  
Loam Soil ◽  
Soil Moisture Budget

Actual evapotranspiration was estimated from the soil moisture budget for a grass-covered sandy loam soil at Simcoe, Ontario. Soil moisture was measured at 25 sites distributed over a 6-meter-square grid. The coefficient of variation for actual evapotranspiration estimated at all sites averaged 13% and rose as high as 19%. Average actual evapotranspiration exceeded both the Penman and Thornthwaite estimates of potential evapotranspiration for three of the six measuring intervals, due to deep seepage losses. The application of corrections for the vertical water movement, determined from experimentally derived matric suction and hydraulic conductivity data, gave a substantial deep seepage loss for some periods and a capillary uptake of soil water for others. Vertical losses and gains created errors of up to + 28 and − 29%, respectively, in the standard estimates of actual evapotranspiration. The large spatial variations in evapotranspiration estimates resulted from variations in volumetric soil moisture between sample points, apparently creating differences in the magnitude and direction of vertical water movement across the terminal depth. The horizontal flux of water between measuring points was relatively unimportant in accounting for the spatial variations.

scholarly journals The Influence of a Water Absorbing Geocomposite on Soil Water Retention and Soil Matric Potential

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1731 ◽  
Author(s):  
Michał Śpitalniak ◽  
Krzysztof Lejcuś ◽  
Jolanta Dąbrowska ◽  
Daniel Garlikowski ◽  
Adam Bogacz
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Water ◽  
Water Retention ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Soil Matric Potential ◽  
Soil Water Retention ◽  
Matric Potential ◽  
Control Samples

Climate change induces droughts that are becoming more intensive and more frequent than ever before. Most of the available forecast tools predict a further significant increase in the risk of drought, which indicates the need to prepare solutions to mitigate its effects. Growing water scarcity is now one of the world’s leading challenges. In agriculture and environmental engineering, in order to increase soil water retention, soil additives are used. In this study, the influence of a newly developed water absorbing geocomposite (WAG) on soil water retention and soil matric potential was analyzed. WAG is a special element made from geotextile which is wrapped around a synthetic skeleton with a superabsorbent polymer placed inside. To describe WAG’s influence on soil water retention and soil matric potential, coarse sand, loamy sand, and sandy loam soils were used. WAG in the form of a mat was used in the study as a treatment. Three kinds of samples were prepared for every soil type. Control samples and samples with WAG treatment placed at depths of 10 cm and 20 cm were examined in a test container of 105 × 70 × 50 cm dimensions. The samples had been watered and drained, and afterwards, the soil surface was heated by lamps of 1100 W total power constantly for 72 h. Soil matric potential was measured by Irrometer field tensiometers at three depths. Soil moisture content was recorded at six depths: of 5, 9, 15, 19, 25, and 30 cm under the top of the soil surface with time-domain reflectometry (TDR) measurement devices. The values of soil moisture content and soil matric potential were collected in one-minute steps, and analyzed in 24-h-long time steps: 24, 48, and 72 h. The samples with the WAG treatment lost more water than the control samples. Similarly, lower soil matric potential was noted in the samples with the WAG than in the control samples. However, after taking into account the water retained in the WAG, it appeared that the samples with the WAG had more water easily available for plants than the control samples. It was found that the mechanism of a capillary barrier affected higher water loss from soil layers above those where the WAG had been placed. The obtained results of water loss depend on the soil type used in the profile.

Effets de la scarification du site sur le micro-environnement

1980 ◽  
Vol 10 (4) ◽  
pp. 476-482 ◽  
Author(s):  
André P. Plamondon ◽  
Denis C. Ouellet ◽  
Gaston Déry
Keyword(s):  
Soil Water ◽  
Air Temperature ◽  
Soil Surface ◽  
The Other ◽  
Maximum Temperature ◽  
Soil Water Tension ◽  
Air Temperatures ◽  
Soil Temperatures ◽  
Water Tension ◽  
Minimum Air Temperature

Soil and air temperatures, and soil water tension were measured at two sites from June 1972 to August 1973 in order to determine the effect of scarification. This study is part of a project concerning yellow birch regeneration. The minimum air temperature at 30 cm height and at the soil surface were, respectively, 0.5 and 1.0 °C higher at the scarified site; on the other hand, the maximum temperature at 30 cm was lower. The soil temperatures during the summer were 2 to 4 °C higher at the scarified site according to the level considered. Soil water tension was much lower in the scarified station between 0 and 15 cm depth, but the effect decreased during the second summer of the study.

scholarly journals Optimizing the Positioning of Soil Moisture Monitoring Sensors in Winter Wheat Fields

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1707
Author(s):  
Xiaojun Shen ◽  
Jing Liang ◽  
Ketema Zeleke ◽  
Yueping Liang ◽  
Guangshuai Wang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Winter Wheat ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Profile ◽  
Root Distribution ◽  
Soil Surface ◽  
Soil Moisture Sensors ◽  
Total Average

Collecting accurate real-time soil moisture data in crop root zones is the foundation of automated precision irrigation systems. Soil moisture sensors (SMSs) have been used to monitor soil water content (SWC) in crop fields for a long time; however, there is no generally accepted guideline for determining optimal number and placement of soil moisture sensors in the soil profile. In order to study adequate positioning for the installation of soil moisture sensors in the soil profile, six years of field experiments were carried out in North China Plain (NCP). Soil water content was measured using the gravimetric method every 7 to 10 days during six growing seasons of winter wheat (Triticum aestivum L), and root distribution was measured using a soil core method during the key periods of winter wheat growth. The results from the experimental data analysis show that SWC at different depths had a high linear correlation. In addition, the values of correlation coefficients decreased with increasing soil depth; the coefficient of variation (CV) of SWC was higher in the surface layers than in the deeper layers (depths were 0–40 cm, 0–60 cm, and 0–100 cm during the early, middle, and last stages of winter wheat, respectively); wheat roots were mainly distributed in the surface layer. According to an analysis of CV for SWC and root distribution, the depths of planned wetted layers were determined to be 0–40 cm, 0–60 cm, and 0–100 cm during the sowing to reviving stages (the early stage of winter wheat), returning green and jointing stages (the middle stage of winter wheat), and heading to maturity stage (the last stage of winter wheat), respectively. The correlation and R-cluster analyses of SWC at different layers in the soil profile showed that SMSs should be installed 10 and 30 cm below the soil surface during the winter wheat growing season. The linear regression model can be built using SWC at depths of 10 and 30 cm to predict total average SWC in the soil profile. The results of validation showed that the developed model provided reliable estimates of total average SWC in the planned wetted layer. In brief, this study suggests that suitable positioning of soil moisture sensors is at depths of 10 and 30 cm below the soil surface.

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