نتایج جستجو برای: biological soil crust

تعداد نتایج: 643786  

Journal: :journal of agricultural science and technology 2010
s. k. alavi panah r. goossens h. r. matinfar h. mohammadi m. ghadiri

a knowledge of soil surface conditions, especially desert crust, salt crust and desert varnish is useful for improving classification of remotely sensed data. desert crust can generate high levels of reflectance, similar to those areas with high salt concentration and non-saline soil. therefore, soil surface crusts might bias thematic remote sensing of soils. in this study, we evaluated the eff...

2003
R. R. Wells

rangement and distribution of the cracks. Moreover, White (1972) explained the energy implications that The theory of water movement in high shrink/swell soils has expericause the cracks to reappear in the same position from enced consistent revision since Haines first presented the topic in 1923. Several aspects of the infiltration process in cracking soils have event to event. Johnston and Hi...

Journal: :international journal of environmental research 0
p. gallardo department of agronomy, university of almeria, spain j. salazar department of economics and business, university of almeria, spain f. j. lozano department of agronomy, university of almeria, spain m. c. navarro department of economics and business, university of almeria, spain c. asensio department of agronomy. university of almeria, spain

the influence of wind erosion on soil productivity was studied applying fan-forced wind in a wind tunnel located in the campo de nijar area in se spain where the main crops are cereals. wind erosion is highly variable depending on the type of soil (aric-haplic calcisols, aric-calcaric cambisols or aric-calcic luvisols, according to iuss working group wrb, 2014) and the time elapsed since the la...

2014
K. Haustein R. Washington J. King G. Wiggs D. Thomas L. Menut

Within the framework of the Dust Observations for Models (DO4Models) project, the performance of three commonly used dust emissions schemes is investigated in this paper using a box model environment. We constrain the model with field data (surface and dust particle properties as well as meteorological parameters) obtained from a dry 5 lake bed with a crusted surface in Botswana during a three ...

2013
Katrin Aschenbach Ralf Conrad Klára Řeháková Jiří Doležal Kateřina Janatková Roey Angel

Methanogens typically occur in reduced anoxic environments. However, in recent studies it has been shown that many aerated upland soils, including desert soils also host active methanogens. Here we show that soil samples from high-altitude cold deserts in the western Himalayas (Ladakh, India) produce CH4 after incubation as slurry under anoxic conditions at rates comparable to those of hot dese...

Journal: :تحقیقات مهندسی کشاورزی 0
عباس همت استاد گروه ماشینهای کشاورزی، دانشکده کشاورزی دانشگاه صنعتی اصفهان سیدمجید عطایی دانش آموخته سابق کارشناسی ارشد مکانیک ماشینهای کشاورزی، دانشکده کشاورزی دانشگاه صنعتی اصفهان

poor stand establishment of canola (brassica napus l.) under flatland mechanized planting and crust-forming soil is a major problem for farmers in central iran. previous research there showed that irrigated cotton emergence on crust-forming soils under flatland planting can be significantly improved using a double-disk planter with zero-pressure press wheel tires and no crust-breaking. in that ...

2016
Isabel Miralles Carmen Trasar-Cepeda Carmen Leirós

Decomposition processes are extremely important in biological soil crusts (BSCs). Although the effects of temperature and moisture on such processes have been widely studied, little is known about the influence of the readily metabolizable substrate (labile C) and how this substrate varies in different types of BSCs. In the present study, BSCs formed by cyanobacteria (CYANO) and by lichens (DIP...

2013
Yaxian Hu Wolfgang Fister Nikolaus J. Kuhn

Sediment generated by interrill erosion is commonly assumed to be enriched in soil organic carbon (SOC) compared to the source soil. However, the reported SOC enrichment ratios (ERSOC) vary widely. It is also noteworthy that most studies reported that the ERSOC is greater than unity, while conservation of mass dictates that the ERSOC of sediment must be balanced over time by a decline of SOC in...

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