Comparison of spatial interpolation techniques for mapping soil pH and salinity in agricultural coastal areas,northern Iran

This study attempted to characterize the spatial distributions of soil pH and electrical conductivity (EC_e) of coastal fields in the Miyandoroud region, northern Iran, for three soil layer depths by assessing spatial variability and comparing different interpolation techniques such as inverse distance weighting (IDW), ordinary kriging (OK), and conditional simulations (CS). Three soil composite samples were collected from 0–50, 50–100, and 100–150 cm depths at 105 sampling sites. At all three soil depths, pH and EC_e were best fitted by exponential and spherical models, respectively. Nugget effects were higher for soil EC_e data sets compared with soil pH at all three soil depths showing soil EC_e had a spatial variability in small distances. The prediction accuracy of the interpolation methods indicated that the minimum error for all data sets was achieved with the OK method, except for pH at 50–100 cm depth, and the CS technique revealed the largest error. The effect of different numbers of simulations (100, 500 and 1000) in the CS interpolation method resulted not in a realistic mapping for the soil EC_e and pH. Considering the high importance of irrigated agriculture in the Caspian Sea coastal areas, more subsoil salinity build-up and groundwater salinity monitoring plans are needed as a prerequisite for sustainable agricultural production systems of the future.     

Geostatistics-based spatial distribution of soil moisture and temperature regime classes in Mazandaran province,northern Iran

Soil moisture regime (SMR) and soil temperature regime (STR) classes as soil classification criterions are required by US Soil Taxonomy because they affect genesis, use, and management of soils. The lack of sufficient soil moisture and temperature data requires the characterization of the pedoclimate on the basis of climatic data processed by simulation models. This research was conducted to consider the new approach for SMR and STR mapping. The objectives of this study were to compare the four interpolation schemes including ordinary kriging (OK), cokriging (Co-K), inverse distance weighting, and conditional simulation for interpolating the monthly mean total precipitation (MMTP) and monthly mean air temperature (MMAT) and to apply the Java Newhall simulation model for the MMTP and MMAT predictive values at each node of 1 km² grids across the Mazandaran province, northern Iran, for delineating the SMR and STR classes. The semivariogram analyses showed moderate to strong spatial dependence of data sets. The accuracy of interpolators varied within months for both MMTP and MMAT data sets. In most cases, OK and Co-K methods had the highest accuracy with lower mean error, root mean square error, and higher concordance correlation coefficient. The predictive maps show high diversity of SMR classes including Aridic, Ustic, Udic, and Xeric. The STR classes comprise Mesic, Thermic, and Cryic regimes. Results herein indicated that geostatistical approaches can potentially provide the opportunity for mapping of SMR and STR classes in data scarce regions.     

Differential responses of three chamomile genotypes to salinity stress with respect to physiological,morphological, and phytochemical characteristics

Effect of water salinity was studied in different Matricaria recutita L. genotypes (Isfahan, Ahvaz, and Shiraz) to understand their protective mechanisms and agronomic performance. Based on a split-plot design arranged in a randomized complete-block consisted of four salinity levels as the main plot and three genotypes as the subplots with three replications this field experiment was conducted in 36 plots with 3 m² space in the Isfahan Center for Research of Agricultural Science and Natural Resources during 2014–2015. The findings showed that the three genotypes differed in resistance to salinity and tolerance mechanisms. They have evolved different physiological, morphological, and biochemical adaptations to salt stress. The Ahvaz genotype in the absence of salt, the Isfahan genotype at 6, and the Shiraz genotype at 9 and 12 dS m^?1 sodium chloride (NaCl) were desirable, taking both quantity and quality into consideration. While preserving shoot growth, the Isfahan genotype was more tolerant to 6 dS m^?1 NaCl most likely due to peroxidase activity. The resistance of the Shiraz genotype is associated with root growth stimulation at 9 and Na compartmentation in root at 12 dS m^?1 NaCl. The Isfahan genotype had the highest oil and chamazulene content, which was not affected by salinity. The Shiraz genotype in the control treatment, the Isfahan genotype at 6 and 9 and the Ahavaz genotype at 12 dS m^?1 NaCl synthesized higher flavonoid compounds.     

Some Engineering Properties of Sunflower Seed and Its Kernel

Some engineering properties of sunflower seed and its kernel, Shahroodi variety as a case study, were investigated at various moisture content levels （3-14% d.b.） for three size categories （large, medium and small）. With increase of moisture content from 3 to 14% d.b., all the main dimensions （length, width and thickness）, geometric mean diameter, porosity, true density, terminal velocity and static coefficient of friction increased while bulk density and rupture force for both sunflower seed and its kernel decreased for all size categories. The results showed that the highest value of static coefficient of friction for both seed and kernel was on the rubber surface, followed by plywood, polyethylene, galvanized iron, and finally aluminium surfaces. The seeds required less compressive force to dehull when loaded under the horizontal as compared to the vertical orientation. But for kernels, the trend was the opposite. Also, the compressive forces needed to initiate rupture of sunflower seed hulls were higher （47.1-94.72 N） than those required to rupture the kernel （8.5-13.4 N） in both orientations.     

Mechanical Properties of Sunflower Seed and Its Kernel,Azargol Variety as a Case Study,under Compressive Loading

The objective of this study was to investigate the effect of moisture content, size and loading orientation on mechanical properties such as force, deformation and energy absorbed per unit volume for fracturing Iranian sunflower seed and its kernel （Azargol as a case study） under quasi-static loading. Sunflower seeds and their kernels were quasi-statically loaded in horizontal and vertical orientations with moisture content in three levels： 3%, 7% and 14%, and size category in three levels： small, medium and large. The obtained results showed that rupture force for both sunflower seed and its kernel decreased with increasing moisture content while the absorbed energy and deformation at rupture point increased for all size categories in both horizontal and vertical loading orientations. Also, seeds in the vertical orientation developed hull cracks at a higher level of force than those loaded in the horizontal orientation. However, for the kernels it was the opposite. In addition, the average forces required to cause kernel rupture were lower （11.64-39.9 N） than those required to rupture the seed （30.06-117.46 N） in both orientations. Seeds loaded in a vertical orientation absorbed more energy （87.67 mJ） prior to rupture than those loaded in the horizontal （46.60 mJ） orientation. However, for the kernels it was the opposite.     

Effect of shifting cultivation on distribution of nutrient elements and carbohydrates within water-stable aggregates in northern Iran

This study attempts to evaluate the nutrient element and carbohydrate distribution within Water-Stable Aggregates (WSA) of two natural ecosystems, native forest and pasturelands, under different land uses. Soil samples were collected from depths of (0-20) cm in Typic Haploxeroll soils. The overall pattern indicated that Mean Weight Diameter (MWD) and WSA were greater in the pasture and forest soils compared with the adjacent cultivated soils and aggregates of > 1.0 mm size were dominant in the uncultivated soils, whereas the cultivated soils comprised aggregates of the size < or = 0.5 mm. Distribution of organic carbon, nitrogen, phosphorus and carbohydrates within the WSA showed preferential enrichment of these parameters in the macroaggregate fraction (4.75-1.0 mm) for the uncultivated soils and microaggregate fraction (> 0.25 mm) for the cultivated soils. Average distribution of total exchangeable bases within WSA showed that cultivation of forest pastureland soils significantly led to reduce in these nutrient in the 4.75-2.0 mm fraction and increase in concentration of these cations in < 0.25 mm fraction. Since smaller aggregates are preferentially removed by erosion, this study emphasizes the need for sustainable soil management practices that they will minimize nutrient loss when forest or pastures lands are converted to cropland.     

Isolation and characterization of potassium solubilizing bacteria in some Iranian soils

The ability of a few soil bacteria to transform unavailable forms of potassium (K) to an available form is an important feature in plant growth-promoting bacteria for increasing plant yields of high-K-demand crops. In this research, isolation, screening, and characterization of six isolates of K solubilizing bacteria (KSB) from some Iranian soils were carried out. The ability of all isolates were tested in three treatments including acid-leached soil, biotite, and muscovite by analyzing the soluble K content after 5 days of incubation at 28 ± 2°C. Identification and phylogenetic analyses were also carried out by morphological, biochemical, and 16S rDNA analyses. Among the six efficient isolates, five isolates belonged to Bacillus megaterium (JK3, JK4, JK5, JK6, and JK7), while isolate JK2 belonged to Arthrobacter sp. The soluble K contents in all isolated-treatments were significantly (p < 0.01) higher than the contents in nonbacteria treatment. Herein, isolate JK2 had lower potential for K solubilization (910 mg kg^?1) compared with other isolates in acid-leached soils. The six bacterial strains showed higher solubilized K in biotite treatment than other two treatments. Overall, it can be concluded that the isolates belong to B. megaterium are the most efficient KSB under in vitro condition.     

Frictional Behavior of Sunflower Seed and its Kernel as a Function of Moisture Content,Variety and Size

The object of this study was to investigate the frictional properties （repose angles and friction coefficient） of Iranian sunflower seed and its kernel （Fandoghi, Azargol and Shahroodi） as a function of moisture content, size and variety. The static coefficient of friction were determined on five structural surfaces including aluminium, plywood, galvanized iron, polyethylene and rubber when moisture content varied between 3 and 14 % d.b. The obtained results showed that static coefficient of friction on five studied surfaces increase linearly as moisture content increase from 3 to 14% for both seed and kernel. Among the applied surfaces, rubber showed the highest value of friction coefficient for both sunflower seed and kernel followed by plywood, polyethylene, galvanized iron and aluminium. The obtained values of emptying and filling angles of repose increase linearly with an increase in moisture content. Furthermore, the values of empting and filling angles of repose for small sizes were higher than big sizes in all levels of moisture content for both seed and kernel. Also, the emptying angle of repose assumed higher values than the filling angle of repose for all varieties and categories.     

Epidural ketamine in the dromedary camel

ObjectiveTo evaluate the clinical and physiological effects of epidural injection of ketamine in camels.Study designRandomized prospective study.AnimalsTen healthy immature male dromedary camels.MethodsKetamine was administered epidurally at doses of 1 and 2 mg kg^?1 (five animals in each treatment). The drug was injected into the first intercoccygeal epidural space. Anti-nociception, sedation, ataxia, and effect on cardiopulmonary, rectal temperature and some selected haematological parameters were recorded at different intervals before (baseline) and after the drug administration. Data were analyzed by anova or U Mann–Whitney tests, as relevant and significance was taken as p < 0.05.ResultsEpidural ketamine at the 2 mg kg^?1 dose produced complete anti-nociception in the tail, anus and perineum, whilst the 1 mg kg^?1 dose produced complete anti-nociception only in the tail. Epidural ketamine resulted in mild to moderate sedation at the 1 mg kg^?1 dose and deep sedation at the 2 mg kg^?1 dose. Ataxia was observed in all test subjects and was severe, resulting in recumbency, in the 2 mg kg^?1 group. Respiratory rate and rectal temperature did not change significantly after injection of either treatment. Following epidural injection of 2 mg kg^?1 of ketamine, heart rate increased significantly from the pre-injection baseline of 55 ± 2 to 76 ± 4 (mean ± SD) beats minute^?1, but after the lower dose changes were not significant. The only significant changes in measured haematologic parameters were decreases in total erythrocyte count at 45 minutes and total leukocyte count from 45–75 minutes, in the 2 mg kg^?1 group.ConclusionEpidural ketamine injection was associated with caudal anti-nociception, sedation and ataxia in the dromedary camels; the intensity and duration of which was dose dependant.Clinical relevanceNeither of the doses of epidural ketamine injection in our study was applicable for standing surgical procedures in dromedary camels.     

Long-term charcoal-induced changes to soil properties in temperate regions of northern Iran

The long-term performance and benefits of charcoal application on the carbon sequestration and properties of forest soils in temperate or non-tropical regions has not been studied in detail in spite of its important role in global warming. This study was conducted to describe the long-term charcoal-induced changes in organic carbon (OC) content and other soil properties of temperate deciduous forests in Mazandaran province, northern Iran. Three sites were sampled to collect composite soil samples from two depths (0–20 and 20–40 cm) inside and outside of a plot of charcoal-enriched soils surrounding a historical charcoal production site (abandoned for more than 120 years). The presence of charcoal in soils for about 120 years elevated significantly the black carbon, total OC, natural soil OC, total nitrogen, dissolved organic matter, soil OC density, exchangeable bases, saturated hydraulic conductivity, available water capacity and available Fe, Mn and Zn compared to the adjacent reference soils. Cation exchange capacity (CEC) and pH were 15.5 cmolc kg^-1 and 0.5 units, respectively, higher than the adjacent reference soils at 0–20 cm soil depth. However, electrical conductivity (EC), bulk density and available Cu were higher in the adjacent reference soil. The aged charcoal had no significant effect on the microbial respiration rate of studied soils. The results of this study provide new insights and strong support for the long-term benefits of biochar application as a management strategy for improving soil productivity as well as sequestering large quantities of durable carbon in soils of the region and mitigating global warming.