scholarly journals Biophysical Effects of Evapotranspiration on Steppe Areas: A Case Study in Naâma Region (Algeria)

2021 ◽  
Author(s):  
Abdelkrim Benaradj ◽  
Hafidha Boucherit ◽  
Abdelkader Bouderbala ◽  
Okkacha Hasnaoui
Keyword(s):  
Mediterranean Climate ◽  
Potential Evapotranspiration ◽  
Thick Layer ◽  
Soil Surface ◽  
Cold Season ◽  
Perennial Grasses ◽  
Herbaceous Plants ◽  
Humid Climate ◽  
Water Losses ◽  
Steppe Vegetation

The Algerian steppe is of great interest in terms of vegetation, mainly in the Naâma region. This steppe vegetation is generally composed of annual and perennial grasses and other herbaceous plants, as well as, bushes and small trees. It is characterized by an arid Mediterranean climate where the average annual precipitation (100 to 250 mm) is insufficient to ensure the maintenance of the vegetation, in which the potential evaporation always exceeds the precipitations. This aridity has strong hydrological effect and edaphic implications from which it is inseparable. Water losses are great than gains due to the evaporation and transpiration from plants (evapotranspiration). The wind moves soils for one location to another, and causes a strong evapotranspiration of the plants, which is explained by a strong chronic water deficit of climatic origin of these compared to the potential evapotranspiration, opposed to a humid climate. Evapotranspiration is certainly closely linked to climate factors (solar radiation, temperature, wind, etc.), but it also depends on the natural environment of the studied region. Potential evapotranspiration (PET) data estimated from Thornthwaite’s method for the three stations (Mécheria, Naâma and Ainsefra). The average annual value of potential evapotranspiration is of the order of 807 mm in Mécheria, of 795 mm in Naâma de and in Ainsefra of 847 mm. It is more than 3 times greater than the value of the rainfall received. This propels it globally in the aridity of the region and from which the water balance of plants is in deficit. The potential evapotranspiration of vegetation in arid areas is very important due to high temperature and sunshine. During the cold season, precipitation covers the needs of the potential evapotranspiration and allows the formation of the useful reserve from which the emergence of vegetation. From the month of April there is an exhaustion of the useful reserve which results of progressive deficit of vegetation. Faced with this phenomenon of evatranspiration, the steppe vegetation of the region then invests in “survival” by reducing the phenomena of evapotranspiration, photosynthetic leaf surfaces, in times of drought. These ecophysiological relationships can largely explain the adaptation of steppe species (low woody and herbaceous plants) to the arid Mediterranean climate. Mechanisms and diverse modalities were allowing them to effectively resist for this phenomenon. The adaptation of the steppe vegetation by the presence of a root system with vertical or horizontal growth or both and seems to depend on the environmental conditions, and by the reduction of the surface of transpiration, and by the fall or the rolling up of the leaves, and by a seasonal reduction of transpiration surface of the plant to reduce water losses during the dry season (more than 6 months) of the year.. Some xerophytes produce “rain roots” below the soil surface, following light precipitation or during dew formation. Other persistent sclerophyllous species by which decreases transpiration by the hardness of the leaves often coated with a thick layer of wax or cutin.

A model for estimating soil moisture deficits under cereal crops in Britain:1. Development

1982 ◽  
Vol 98 (3) ◽  
pp. 651-661 ◽  
Author(s):  
P. E. Francis ◽  
J. D Pidgeon
Keyword(s):  
Potential Evapotranspiration ◽  
System Development ◽  
Free Water ◽  
Soil Surface ◽  
Cereal Crops ◽  
Water Losses ◽  
Crop Species ◽  
Detailed Model ◽  
Stage Of Development ◽  
Wide Range

SUMMARYA new and detailed model, involving meteorological, crop and soil variables, is proposed to provide daily estimates of moisture deficits in soils under cereal cropping in Britain. The model incorporates developments in the calculation of potential evapotranspiration specifically for cereal crops. Four processes of loss of water are considered, namely drainage, evaporation of free water from the crop canopy, evaporation from the soil surface and transpiration by the crop. Thus the model is applicable at all stages of the cropping cycle. Above-ground and root system development of the crop are modelled and available and extractable water capacities of a wide range of soils are estimated. Thus the demand for water and its availability are varied with crop species, stage of development and soil type as well as with meteorological variables.The calculation of water losses is not dependent on arbitrary assumptions about the division of losses between the four processes considered or between different horizons of the soil.Extreme simplicity of input data requirement has been maintained. The model has been programmed in FORTRAN, and is compatible with Meteorological Office data archives.

Establishment of introduced grasses at different stages of pasture development: effects of seedbed

1981 ◽  
Vol 21 (111) ◽  
pp. 417 ◽  
Author(s):  
JG McIvor ◽  
CJ Gardener
Keyword(s):  
Plant Competition ◽  
Thick Layer ◽  
Soil Surface ◽  
Perennial Grasses ◽  
Wet Season ◽  
Stylosanthes Hamata ◽  
Native Grassland ◽  
Successful Establishment ◽  
Chloris Gayana ◽  
Seedbed Preparation

The seedbed preparation necessary for the successful establishment of five promising perennial grasses for the dry tropics was studied on two pastures - native grassland and a pasture dominated by Stylosanthes hamata cv. Verano - near Townsville, in northern Queensland. Seed of Cenchrus ciliaris cv. Biloela, Chloris gayana cv. Callide, Chrysopogon sp. CPI 5221 3, Digitaria milanjiana CPI 5981 4 and Urochloa mosambicensis CPI 46876 was sown into the two pastures, which had been left untreated, sprayed with herbicide, burnt, or burnt and cultivated. S. hamata cv. Verano was also sown on the native grassland plots. Sowings were made at the start of the growing season in successive years. Germination of all lines was adequate except where a thick layer of green and dead herbage physically separated the seed from the soil surface; this happened on the native pasture plots that were untreated or herbicide treated. However, there was high plant mortality in the first month after sowing except where plant competition had been reduced or removed by cultivation or spraying. After this period, most plants survived to the end of the wet season in both pasture types. This pattern of change in plant numbers resulted in good establishment on the cultivated seedbeds, some establishment on the herbicide-treated plots and little or no establishment on the control and burnt plots. Of the five grasses, U. mosambicensis had the best establishment and Chrysopogon sp. and D. milanjiana the worst. None seem likely to survive when sown into living grassland. We therefore conclude that the use of these introduced species will be largely restricted to completely cleared and cultivated land.

scholarly journals Phenology of ectomycorrizal fungi in subtropical evergreen Castanopsis forest

2010 ◽  
Vol 6 ◽  
pp. 8-11 ◽  
Author(s):  
Morten Christensen
Keyword(s):  
Mycorrhizal Fungi ◽  
Mediterranean Climate ◽  
Monsoon Rainfall ◽  
Cold Season ◽  
Plant Science ◽  
Mountainous Areas ◽  
Humid Climate ◽  
Central Nepal ◽  
Winter Rain ◽  
High Diversity

The mycota of Himalaya is poorly described and information on the ecology of ecto-mycorrhizal species in the region is very limited. Three years (2004-2006) of intensive studies of the fruitbodies in Schima-Castanopsis forest in Central Nepal have documented a high diversity of ecto-mycorrhizal fungi. Systematic information collected from five forests in the surrounding of Pokhara are analyzed to describe the phenological patterns. The species diversity of fruitbodies is highest just after the first pre-monsoon rainfall in late May to early July and by the late monsoon rain of September and early October. Similar bimodular patterns are described from areas with warm humid climate in Japan. In cold Temperate and Boreal areas in Europe and North America as well as in the mountainous areas of Nepal only one peak of the ecto-mycorrhizal fungi is found. In these areas the temperature seems to be the main agent in determining the time of fructification of the ecto-mycorrhizal fungi. In contrast studies from Subtropical Mediterranean climate in Southern Europe with winter rain found fructification in the cold season, indicating that moisture is more crucial for the fruitbody creation than temperature in subtropical areas. Key-words: Central Nepal; ecto-mycorrhiza; Himalaya; Schima-Castanopsis forest.DOI: 10.3126/botor.v6i0.2904 Botanica Orientalis - Journal of Plant Science (2009) 6: 8-11

Technologies of drop irrigation of young almond garden on terraces in foothland conditions of the Kyzylsu-Yuzhnaya river basin

2021 ◽  
Vol 0 (1) ◽  
pp. 12-15
Author(s):  
Daler Domullodzhanov
Keyword(s):  
River Basin ◽  
Drip Irrigation ◽  
Field Experiments ◽  
Soil Surface ◽  
Perennial Grasses ◽  
Minimum Amount ◽  
Almond Orchard

The article presents the results of field experiments on the study of the technology of drip irrigation of a young almond orchard on terraces with clear cover with tillage soil surface, with use of mulching and overseeding of perennial grasses. In the variant with mulching, the minimum amount of irrigation observed – 24, with the irrigation norm – 1904 litre per tree. In other cases, the number of irrigation events increases from 8 to 23, respectively, the irrigation norms are 1.39 and 2.06 times.

Growth, seed production and effect of defoliation in an early flowering perennial grass, Alloteropsis semialata (Poaceae), on Cape York Peninsula, Australia

2001 ◽  
Vol 49 (6) ◽  
pp. 735 ◽  
Author(s):  
Gabriel M. Crowley ◽  
Stephen T. Garnett
Keyword(s):  
Plant Growth ◽  
Seed Production ◽  
Perennial Grass ◽  
Soil Surface ◽  
Plant Size ◽  
Perennial Grasses ◽  
Wet Season ◽  
Cape York ◽  
Seed Dynamics

Alloteropsis semialata (R.Br.) A.Hitchc. is one of the first perennial grasses in monsoonal Australia to produce seed at the start of the wet season. Patterns of growth and seed production and seed dynamics of Alloteropsis semialata were examined in this study, along with the effects of partial defoliation. Growth of Alloteropsis semialata tussocks started with the first pre-wet-season rains, and was then interrupted during a period with little rain. Growth ceased before the end of the wet season, indicating that factors other than moisture availability were limiting. Seeds of Alloteropsis semialata were germinable on production, but did not remain viable or persist on the soil surface through the dry season. Most seeds and young seedlings were harvested and no seedlings were recruited. Inflorescence production increased with plant size. Moderate defoliation in the early wet season had no impact on plant growth, but reduced inflorescence and seed production for at least 2 years. Absence of a seed bank and early wet-season flowering mean that Alloteropsis semialata is likely to be sensitive to long-term over-grazing.

A Python-based GIS Simulation of the Spatial and Temporal Variation in Evapotranspiration

2019 ◽  
Vol 35 (5) ◽  
pp. 759-765 ◽  
Author(s):  
Mohammed G. Mohammed ◽  
Kathleen M. Trauth
Keyword(s):  
Overland Flow ◽  
Potential Evapotranspiration ◽  
Spatial And Temporal Variation ◽  
Spatial And Temporal Variability ◽  
Water Losses ◽  
Python Script ◽  
Space And Time ◽  
Land Covers ◽  
A Site ◽  
Linn County

Abstract. An assessment of potential evapotranspiration (ET) and direct evaporation is important for informed land management from agriculture to wetlands restoration. These processes vary in space and time, depending on vegetation, soils, and climate throughout the year. Much data has been collected in order to quantify ET for individual plots of land, but means have not been available to provide an integrated view on a landscape scale. A methodology has been developed and an implementing Python script has been written to assess and display the spatial and temporal variability of ET and direct evaporation using a geographic information system (GIS). The methodology utilizes publicly available inputs for broad applicability, and the calculations can be performed for a site with multiple land covers and soil textures. In addition to a visual representation of ET and direct evaporation in space and time, the Python script produces a text file of water losses that could be used in water balance calculations also incorporating precipitation, overland flow and infiltration. The methodology has been demonstrated on a site within Pershing State Park in Linn County, Missouri, and produces results consistent with those expected from hand calculations. All data and code are available in GitHub (https://github.com/TrauthK/Wetlands). Keywords: Evapotranspiration, Evaporation, GIS simulation, Hydrologic modeling, Hydrologic cycle, Python, Raster data, Wetland restoration.

scholarly journals Losses of soil, water, organic carbon and nutrients caused by water erosion in different crops and natural savannah in the northern Amazon

2018 ◽  
Vol 14 (1) ◽  
pp. 1
Author(s):  
Fernando Gomes de Souza ◽  
Valdinar Ferreira Melo ◽  
Wellington Farias Araújo ◽  
Thiago Henrique de Castro Araújo
Keyword(s):  
Organic Carbon ◽  
Soil Water ◽  
Plant Cover ◽  
Soil Surface ◽  
Bare Soil ◽  
Water Erosion ◽  
Brachiaria Brizantha ◽  
Water Losses ◽  
Agricultural Areas ◽  
The Impact

Currently in Brazil, the main form of erosion is caused by the impact of raindrops on the soil surface, triggering the process of water erosion and causing serious damage to agricultural areas. This study evaluated losses of soil, water, organic carbon and nutrients in different cultures, bare soil and savanna under natural rain. The experimental design was completely randomized with five treatments (bare soil - BS, cowpea bean - CB, Brachiaria brizantha - BB, corn - CO and natural savanna – SN) with three replications; The treatment of bare soil (BS), followed by the treatment cultivated with cowpea bean  (CB) showed higher losses of soil, water, organic carbon and nutrients; The highest losses of soil, water, organic carbon and nutrients in the treatment of bare soil (BS) occurred during the period of greatest erosivity; but for treatments CB, BB and CO, the highest losses occurred during the establishment of the crop, in view of the lower soil cover. Soils cultivated with Brachiaria brizantha - BB, corn - CO and in the Natural Savana - SN area were more efficient in reducing soil and water losses during all months evaluated. Plant cover produced by the (SN) treatment and by the (BB) and (CO) treatments acted to reduce the harmful effects of erosion, minimizing losses of nutrients and organic carbon. The soil should be well protected during periods when rainfall presents the highest values of erosivity index.

scholarly journals Smog Nitrogen and the Rapid Acidification of Forest Soil, San Bernardino Mountains, Southern California

2007 ◽  
Vol 7 ◽  
pp. 175-180 ◽  
Author(s):  
Yvonne A. Wood ◽  
Mark Fenn ◽  
Thomas Meixner ◽  
Peter J. Shouse ◽  
Joan Breiner ◽  
...  
Keyword(s):  
Southern California ◽  
Mediterranean Climate ◽  
Rapid Change ◽  
Soil Surface ◽  
Atmospheric Nitrogen ◽  
Wet Season ◽  
San Bernardino Mountains ◽  
San Bernardino ◽  
Fog Deposition ◽  
Very High

We report the rapid acidification of forest soils in the San Bernardino Mountains of southern California. After 30 years, soil to a depth of 25 cm has decreased from a pH (measured in 0.01 M CaCl2) of 4.8 to 3.1. At the 50-cm depth, it has changed from a pH of 4.8 to 4.2. We attribute this rapid change in soil reactivity to very high rates of anthropogenic atmospheric nitrogen (N) added to the soil surface (72 kg ha–1 year–1) from wet, dry, and fog deposition under a Mediterranean climate. Our research suggests that a soil textural discontinuity, related to a buried ancient landsurface, contributes to this rapid acidification by controlling the spatial and temporal movement of precipitation into the landsurface. As a result, the depth to which dissolved anthropogenic N as nitrate (NO3) is leached early in the winter wet season is limited to within the top ~130 cm of soil where it accumulates and increases soil acidity.

scholarly journals Oribatid mites (Acari, Oribatida) of steppe vegetation on cape Tarhankut in Crimea (Ukraine)

2009 ◽  
Vol 46 (2) ◽  
pp. 97-103 ◽  
Author(s):  
Stanisław Seniczak ◽  
Sławomir Kaczmarek ◽  
Anna Seniczak
Keyword(s):  
Central Asia ◽  
Age Structure ◽  
Mediterranean Region ◽  
Mediterranean Climate ◽  
Vegetation Type ◽  
Sea Breeze ◽  
Oribatid Mites ◽  
Steppe Vegetation ◽  
Geographic Expansion ◽  
The Mediterranean

Oribatid mites (Acari, Oribatida) of steppe vegetation on cape Tarhankut in Crimea (Ukraine)Oribatid mites were investigated in patches of steppe vegetation, dominated by esparto (Stipasp.), other grasses,Artemisia caucasica, Sedumsp., mosses, or lichens, on cape Tarhankut in Crimea (Mediterranean climate). These mites were quite abundant and rich in species there, probably thanks to the fresh sea breeze and geographic expansion of species from the Mediterranean region, Central Asia, and Europe. They achieved the highest density in patches of steppe grasses other than esparto, but most species occurred in sedum patches. The most abundant wasTectocepheus velatus, especially in patches of steppe grasses other than esparto, and relatively abundant wereScutovertexsp. 1,Jacotella neonominataandScheloribates laevigatus. In populations of these species the adults usually dominated, but their age structure greatly depended on vegetation type.

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