Hadi Radnezhad; behzad Behtari; Ali Asghar naghipour Borj; Shole Haj Agfha Memar
Volume 23, Issue 4 , March 2017, , Pages 760-771
Abstract
Plant growth-promoting rhizobacteria are a subset of bacteria, accumulating on the root and rhizosphere. One of the seed priming methods is the use of microorganisms in seed inoculation, known as biopriming. The use of these microorganisms in seed inoculation leads to increased plant performance, especially ...
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Plant growth-promoting rhizobacteria are a subset of bacteria, accumulating on the root and rhizosphere. One of the seed priming methods is the use of microorganisms in seed inoculation, known as biopriming. The use of these microorganisms in seed inoculation leads to increased plant performance, especially if the microorganisms are symbiotic in the root zone of the plants. This study was aimed to investigate the effects of biopriming with Azospirillum and Azotobacter on drought resistance in fescue under greenhouse conditions. Osmotic potential at four levels was applied on the Fescue seeds using polyethylene glycol for 2 and 4 days as priming treatment along with inoculation with rhizobacteria. Drought stress was applied during the plant growth based on field capacity at four levels. The results showed that biopriming treatments caused improved performance and increased drought resistance compared to the control. The study showed that both Azospirillum and Azotobacter increased the performance significantly compared to the control. Generally, Azotobacter showed relatively better performance than Azospirillum. However, the Azotobacter treatments at 2 and 0.5 MPa for 2 days can be considered as a superior treatment in fescue as compared with other treatments.
Ali Asghar Naghipour borj; Jamaladdin Khaeddin; Hosein Bashari; Majid iravani; Pejman Tahmasebi
Volume 23, Issue 3 , January 2017, , Pages 442-453
Abstract
The structure and composition of plant communities are mainly affected by fire and grazing, especially in arid and semiarid rangelands. This study aimed to investigate the role of fire and grazing on soil seed bank characteristics (density, diversity and species richness) in semi-steppe rangelands of ...
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The structure and composition of plant communities are mainly affected by fire and grazing, especially in arid and semiarid rangelands. This study aimed to investigate the role of fire and grazing on soil seed bank characteristics (density, diversity and species richness) in semi-steppe rangelands of Central Zagros. A stratified random sampling was used to collect the data from 12 sites with one and five years after the last fire, and with long term light and heavy grazing history. Soil samples were collected in the autumn by auger from 0-5 and 5-10 cm from the soil surface, and the samples were cultivated in the greenhouse. All the germinated seeds were identified and counted for a 6-month period. The results showed that the one year after fire treatment under both light and heavy grazing resulted to a significant decrease in density, richness, and diversity of the soil seed bank. The richness and diversity of soil seed bank in the five-year after fire treatment and under light grazing pressure increased significantly compared to its control site. According to the results, the soil seed bank in 5 to 10 cm from the soil surface did not vary statistically under fire and grazing pressure, indicating the role of soil depth in reducing the impact of fire and grazing. Overall, it can be concluded that the grazing management after a fire event has a key role in vegetation restoration through its effects on the soil seed bank.
Maryam Heidarian Aghakhani; Ali asghar Naghipour Borj; Hosein Tavakoli
Volume 17, Issue 2 , September 2010, , Pages 243-255
Abstract
It is important to know soil propoerties, particulary its chemical aspects, for the proper management of rangeland ecosystems. The aim of this study is to find the impact of grazing on vegetation and some soil chemical properties, in three areas, the key, reference, and critical, Sisab rangelands, Bojnord. ...
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It is important to know soil propoerties, particulary its chemical aspects, for the proper management of rangeland ecosystems. The aim of this study is to find the impact of grazing on vegetation and some soil chemical properties, in three areas, the key, reference, and critical, Sisab rangelands, Bojnord. The vegetation cover data was collected from 30, 1m2 quadrats in each area through random –systematic method. The soil data was sampled from two depths 0-15, 15-30 cm and five composite samples were collected (each sample was mixed of six samples) from each depth in the each area. Some factors such as the organic carbon, the percentage of soil organic matters, total nitrogen, absorbable phosphorus, pH and EC were measured. The results showed that carbon, nitrogen, soil organic matters, phosphorus, and EC were been decreased by grazing, but pH was increased. According to results, forbs were the dominant life form in the reference site. Shrubs cover percentages were been increased as grazing increased. In addition, reference site had species that are more palatable and invaders were more abundant in critical area. It was concluded that heavy grazing intensity cause to decrease of vegetaton and conversion of composition of the species cause to negative conversion in alimentary mineral of soil, sustainable of ecosystem would be endangered.
Aliasghar Naghipour Borj; Ghasemali Dianati Tilak; Hosein Tavakoli; Maryam Haidarian Aghakhani
Volume 16, Issue 3 , December 2009, , Pages 375-385
Abstract
Climate change and increase of global warming is one of the most important challenges in sustainable development, which is due to increase of concentration of greenhouse gasses in atmosphere. CO2 is the main part of greenhouse gasses. In order to mitigate atmospheric CO2 and create balance in greenhouse ...
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Climate change and increase of global warming is one of the most important challenges in sustainable development, which is due to increase of concentration of greenhouse gasses in atmosphere. CO2 is the main part of greenhouse gasses. In order to mitigate atmospheric CO2 and create balance in greenhouse gasses, atmospheric carbon must be absorbed and sequestrated in different forms. Rangelands ecosystems have approximately half of the worldٰs land area and they store over third of trrestrial biospher carbon. In order to evaluate the effect of grazing intensity on content and distribution of soil carbon sequestration and plant biomass, a study was carried out at Sisab semiarid rangelands of North Khorasn province. After survey, three sampling area has been specified (reference, key and critical). The content of above ground and under ground biomass carbon, litter carbon and soil organic carbon (in two depths 0-15, 15-30 cm) was determined in three area. The result showed that the total carbon sequestration in reference area was 39.79 ton/ha, in key area was 28.97 ton/ha and in critical area was 24.43 ton/ha. The results of carbon distribution showed that the soil organic carbon content was >97% of total carbon sequestration, In addition the carbon content in underground biomass was higher than above ground biomass. It was concluded that the grazing intensity cause to decrease of vegetation cover, content of plant biomass and decrease of carbon sequestration in soil and vegetation biomass, and soil is the most impotant sink for organic carbon storage in this rangelands.