Wind erosion is one of the main drivers of soil loss in the world, which affects 20 million hectare land of Iran. Besides the soil loss, wind erosion contributes to carbon dioxide emission from the soil into the atmosphere. The objective of this study is to evaluate monthly and seasonal changes in carbon dioxide emission in four classes i.e., low, moderate, severe and very severe soil erosion and the interactions between air temperature and wind erosion in relation to carbon dioxide emission in the Bordekhun region, Boushehr Province, southwestern Iran. Wind erosion intensities were evaluated using IRIFR (Iran Research Institute of Forests and Ranges) model, in which four classes of soil erosion were identified. Afterward, we measured carbon dioxide emission on a monthly basis and for a period of one year using alkali traps in each class of soil erosion. Data on emission levels and erosion classes were analyzed as a factorial experiment in a completely randomized design with twelve replications in each treatment. The highest rate of emission occurred in July (4.490 g CO 2 /(m 2 •d)) in severely eroded lands and the least in January (0.086 g CO 2 /(m 2 •d)) in low eroded lands. Therefore, it is resulted that increasing erosion intensity causes an increase in soil carbon dioxide emission rate at severe erosion intensity. Moreover, the maximum amount of carbon dioxide emission happened in summer and the minimum in winter. Soil carbon dioxide emission was just related to air temperature without any relationship with soil moisture content; since changes of soil moisture in the wet and dry seasons were not high enough to affect soil microorganisms and respiration in dry areas. In general, there are complex and multiple relationships between various factors associated with soil erosion and carbon dioxide emission. Global warming causes events that lead to more erosion, which in turn increases greenhouse gas emission, and rising greenhouse gases will cause more global warming. The result of this study demonstrated the synergistic effect of wind erosion and global climate warming towards carbon dioxide emission into the atmosphere.
Obesity/bariatric surgery is rising as the most effective treatment for obesity. In previous studies, the history of Helicobacter pylori as the main cause of chronic abdominal pain in patients undergoing bariatric surgery has not been discussed. In this study, we determine in a set of patients how much of the number of people with positive H. pylori before the operation in one year later suffered from chronic abdominal pain. A retrospective study was conducted on 320 patients undergoing bariatric surgery. Data were collected by interviewing and referring to the medical records of patients. Of 320 patients, 125 were H. pylori-positive, and from these numbers, 43 had chronic abdominal pain (34.4%). Although in previous studies of bariatric surgery, the history of H. pylori has not been identified as the main cause of chronic abdominal pain after surgery. However, according to the available evidence in this study, with a prevalence of more than one-third of chronic abdominal pain in one year after surgery in patients with a history of preoperative H. pylori, pylori can be a potential cause of postoperative chronic pain.
Soil is the fundamental component of each terrestrial ecosystem, so the consequences of land management regime on soil health and productivity should be evaluated. To this end, the long term effects of livestock grazing management on soil health were studied in three land management systems of north-eastern Iran, comprising unlimited grazing, managed grazing, and a rangeland where grazing was prohibited. First, properties including pH, EC, bulk density and contents of phosphorus, potassium and calcium in soils subject to the three grazing management regimes were compared. Then, seasonal variations of organic carbon, total nitrogen, microbial respiration (BR and SIR), carbon and nitrogen of microbial biomass (MBC and MBN), fungal biomass and AMF (Arbuscular mycorrhizal fungi) spore density were studied at the three sites. Several soil stoichiometric microbial indicators were also compared. Soil phosphorus contents were found to drastically decline (by around 40%) in response to long term unlimited grazing, while soil acidity and bulk density slightly increased under that grazing regime, in comparison with managed-grazing and grazing-excluded rangelands. Season and grazing management had significant impacts on all the studied variables. Although soil nitrogen content increased, presumably due to livestock urine, organic carbon content and all the soil microbial variables declined in grazed sites, which were also the ones with lower plant cover. A higher AFM spore density was observed around the rhizosphere of Artemisia aucheri, the most frequent plant, in lands with unlimited grazing. Based on these results, managed grazing is strongly recommended rather than any kind of unlimited or continuous grazing.
Plant light absorption and extinction may affect plant growth and yield. A split plot experiment (with three replications) was carried out in the Research Field of Agricultural College, Islamic Azad University, Isfahan, Iran, during 2011-2012 in order to determine the influence of light absorption and extinction on barley growth and yield. Planting dates including Oct 10th (P1), 25th (P2), and Nov 10th (P3) and plant genotypes including Nosrat (N), 4Shur (S), and Fajr 30 (F) were used as the main-and sub-plots, respectively. Plant growth and yield as well as crop light absorption and extinction were determined at different growth stages. Using a light meter, the rate of photosynthetically active radiation of canopy in the range of 400-700 nm was determined (41-57%). Light extinction coefficients (0.355-0.485) were also determined according to the Beer-Lambert law. Planting dates and genotypes significantly affected crop growth, yield, and response to light. S resulted in the highest rate of light extinction and absorption at P1 and P3, respectively, and it also resulted in the highest rate of grain yield (4228 kg ha −1 ) and harvest index (40.9). These results indicated the positive correlation between the growth and yield of barley genotypes with light absorption and extinction. Such findings can be used for a more efficient designing of a barley canopy with higher growth and yield.
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