نتایج جستجو برای: china j arid land reaserch and management

تعداد نتایج: 17082021  

2005
RATTAN LAL

Drylands occupy 6 15 billion hectares (Bha) or 47 2% of the world's land area Of this, 3 5 to 4 0 Bha (57%65%) are e~ther deserl~fied or prone to deserlificat~on Desp~te the low soil organic carbon (SOC) concentratlon, total SOC pool of soils of the drylands IS 241 Pg (1 Pg = petagram = 10" g = I billion metrlc ton) or 15 5% of rhe world's rota1 of 1550 Pg to 1 -meter depth Desertification has ...

Arid and semi-arid regions with highly variable rainfall and periods of drought or unpredictable floods have severely affected residents' water shortages and they are often living in insecure areas. Rainwater catchment systems are one of the available solutions to overcome water shortage and runoff management in these areas. Surface runoff is a potential source of water that, with proper manage...

Journal: :ecopersia 0
yahya parvizi assistant professor, department of soil conservation and watershed management, agriculture and natural resource research center of kermanshah, areeo, kermanshah, iran mosayeb heshmati assistant professor, department of soil conservation and watershed management, agriculture and natural resource research center of kermanshah, areeo, kermanshah, iran mohammad gheituri assistant professor, department of soil conservation and watershed management, agriculture and natural resource research center of kermanshah, areeo, kermanshah, iran

the effects of different climatic, soil, geometric, and management factors on soil organic carbon (soc) degradation and sequestration potential was evaluated in the semi-arid zone of mereg watershed, west of iran. two nonparametric methods, viz. classification and regression tree (cart) and feed forward back propagation artificial neural network (ann) were compared with parametric multivariate ...

Arid ecosystems and deserts cover much of the Iran’s land. These areas are exploited by local communities. Considering the importance of the conservation and development of natural ecosystems in the arid regions, a study was done to assess factors influencing usage of rangeland conservation practices by exploiters through combination of survey methods and case study in arid rangeland of B...

2012
M. R. Mustapha H. S. Lim M. Z. MatJafri

Arid environment is a dry landscape or region that received an extremely low amount of precipitation. Arid areas are located where vegetation cover is sparse to almost nonexistent. Almost one third of earth land surface is arid or desert. Over desert areas, a number of land cover patterns can be observed. One example is given here for the Arabian Peninsula. The located area can be found in Fig....

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده مدیریت 1392

data envelopment analysis (dea) is a powerful tool for measuring relative efficiency of organizational units referred to as decision making units (dmus). in most cases dmus have network structures with internal linking activities. traditional dea models, however, consider dmus as black boxes with no regard to their linking activities and therefore do not provide decision makers with the reasons...

2013
Xiubin Li Gergely Tóth Chunyuan He

To secure adequate food supply is the major challenge for humanity in the 21st century. Growing world population andits urbanization put pressure on this basic need, which is further threatened by the constant loss of fertile land. Theassessment of sustainability of food supply under increasing pressure on land resources has been selected as one of themost important priority topics ...

G. A. Heshmati V. R. Squires

Rangeland ecosystems shift across dynamic thresholds between differentecological states in response to natural or human-induced factors. These differentecological states are the result of interactions among climate, soils, grazing history,and management practices. The notion of a single ‘‘pristine’’ final state is onlyconceptual in nature, and because of this, dynamic thresholds and the effects...

2005
Y. CHEN H. TANG

Desertification in north China is ongoing despite the endeavours to mitigate it over the past 50 years. Overall examination of the context of desertification and defects of desertification-combating programmes is a prerequisite for desertification control, which is now attracting general concern in China. The physiographic circumstances of north China, including the dry, continental, mid-latitu...

Journal: :environmental resources research 2014
hamid reza asgari

desertification leads to decrease in the ecosystem c pool and attendant reduction in soil organic carbon (soc). reclamation of sandy land in arid and semi-arid has a high potential to increase carbon sequestration and improving soil quality. our objective as to examine the changes in the soil carbon sequestration and soil properties of two soil layers (0–20 and 20-50 cm) under two types of recl...

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