Keywords: Chemical Forms of Iron, Concentration, Corn, Iron Uptake, Sequential Extraction

Neda Pashapoor1, Adel Reyhanitabar2*, Shahin Oustan2     Received: June 19, 2015    Accepted: February 14, 2016 1-Graduated MSc Student of Soil Science, Faculty of Agriculture, University of Tabriz, Tabriz, Iran. 2- Assoc. Prof., Dept. of Soil Science, Faculty of Agriculture, University of Tabriz, Tabriz, Iran. *Corresponding Author: [email protected]       Abstract       Iron (Fe) is the most important micronutrient for crops that has low availability in calcareous soils. Phytoavailability of Fe depends on the relative distribution of different chemical Fe forms in soil, which is function of soil properties. In this greenhouse research, total Fe fractionated into different forms by sequential extraction procedure was studied in 21 soil samples that varied in physical and chemical properties. According to the results, different Fe fractions concentration were as: Residual iron (Fe-Res)> iron associated with the crystalline iron oxides (Fe-CFeOX)> iron associated with the amorphous iron oxides (Fe-AFeOX)> manganese- oxide- associated Fe (Fe- MnOX)> organic matter-associated Fe (Fe-OM)> exchangeable iron (Fe-Ex) ≥ carbonates-bound iron (Fe-Car).  Fe-Ex, Fe-OM, Fe-AFeOX, Fe-CFeOX, Fe-Res and available iron (Fe-DTPA) had a significant relationship with corn shoot and root dry matter, active iron content, chlorophyll index and shoot iron uptake. Correlation coefficient showed that the Fe-Ex, Fe-AFeOX and Fe-Res had a close and significant relationship with all measured agronomical traits of corn. It is concluded that, these forms of iron are probably the source of available iron for corn in studied soils

Effect of Nitrohumic Acid Application on Some Morphological and Physiological Characteristics of Savory Plant (Satureja hortensis L.)

Introduction Savory is considered one of the most important medicinal plants, which is used in various food and medical industries. Nitrogen (N) plays a major role on the growth and yield of medicinal plants. Therefore, an adequate supply of N is required for successful production of savory. However, the application of chemical N fertilizers is associated with many obstacles such as groundwater ‎pollution, N enrichment of surface waters, and drop in the quality of plants. ‎Accordingly, nowadays, great attention has been paid to organic fertilizers. In this regard, humic acid-based fertilizers have shown promising results. Humic acids (HAs) could be converted into nitrohumic acids (NHAs) through the nitration process, in which nitro groups (NO2) are located on the aromatic rings. This process increases the N content of the HA. Thus, ‎‎NHAs can be used as organic N fertilizers in the cultivation of medicinal plants whose organic production is a priority. However, the ‎effects of these types of fertilizers on plant growth and physiological characteristics have not been well ‎understood. Accordingly, the present study for the first time investigates the effectiveness of NHA on the ‎morphological and physiological characteristics of savory, as well as N loss through leaching.‎ Materials and Methods In the current study, HA was initially extracted from leonardite (purchased from Yazd Golsang Kavir Company) as a rich source of HA. Then, NHA was prepared through the nitration process using nitric acid (50% by volume). After that, using FT-IR (Fourier transform infrared spectroscopy) and CHNS analysis the extracted HA and NHA were characterized, and their N content was determined. Afterward a ‎greenhouse experiment in a completely randomized design (CRD) with three replications was conducted ‎to determine the effects of 16 treatments, including control (without urea, HA and NHA), urea (U1, U2 and U3), humic acid ‎‎(HA1, HA2 and HA3), nitrohumic acid (NHA1, NHA2 and NHA3), urea-humic acid (U1HA1, U2HA2‎ and U3HA3), and urea-nitrohumic acid (U1NHA1, U2NHA2 and U3NHA3) on the morphological ‎and physiological characteristics of savory plant. The treatment levels were ‎determined as 40, 80, and 120 mg N kg-1 for the first, second and third level of the treatments, respectively. In the combined treatments of urea and HA or NHA, an equal fraction of the total nitrogen (N) was applied. At the end of the experiment, standard methods were used to assess various characteristics, including root length, leaf area, plant height, root volume, wet and dry weights of shoot and root, leaf chlorophyll index, concentrations of phosphorus, potassium, nitrogen, nitrate, and nitrate reductase in both the shoot and root. Additionally, leaching was conducted on specific days during the experiment, and the leachate was collected for nitrate measurement. Results and Discussion The results showed that using the nitration process, some characteristics of the NHA such as total acidity, the content of carboxylic and phenolic groups as well as N content improved as compared to the initial HA. Moreover, the results indicated that most of the morphological and physiological ‎traits of savory plants, including leaf area, plant height, root length, fresh and dry weights of root and shoot as well as chlorophyll index, and the concentration of nitrogen, phosphorous, potassium, nitrate and nitrate reductase enzyme were significantly higher in the NHA treatments than those of HA. In addition, the highest shoot dry weight was obtained in the combined treatments of U3NHA3 and U3HA3 as well as in the U3 treatment alone. The average rate of nitrate concentration increase in the U treatments was 1.77 times higher than the UNHA treatments. According to the results, U3 treatment indicated the highest nitrate loss which by using the U3NHA3 treatment, the mean concentration of nitrate ‎in the leachate decreased by about 40.5% as compared to the U3 treatment.‎ Conclusion The findings of this research revealed that most of the morphological and physiological ‎traits of savory plant showed better responses to the combined treatments of U3NHA3 and U3HA3 as well as to the U3 treatment alone. However, with regard to the lower accumulation of nitrate in the shoot of savory as well as to the lower nitrate leaching, the combined treatments were preferred. Accordingly, NHA can be ‎a alternative nitrogen source in increasing the yield and growth indicators of savory. However, the reasons behind the fact of the better performance of combined nitrogen treatments than the individual ones require more research in the future

Effect of Different Levels of Selenium and Sulfur on Growth and Yield of Three Cultivars of Spring Wheat (Triticum aestivum L.)

Selenium is an essential element for human and animal heath, with antioxidant and anti-cancer properties. Although, researchers have found it to increase vegetative growth. It is not considered to be essential for higher plants. In order to evaluate the effect of selenium and sulfur on growth and yield of three cultivars of spring wheat a factorial experiment based on randomized complete  block design with three replicates was conducted in pots at the Agricultural Faculty of Islamic Azad University, Tabriz Branch, Iran, during 2009-2010. Treatments were 3 cultivars of spring wheat (Karaj, Pishtaz and Sepahan), 5 levels of selenium (0, 0.2, 2, 5 and 10 mg/kg) in the form of sodium selenate used and 4 levels of elemental sulfur (0, 50, 100 and 150 mg/kg). Results showed that 0.2 and 2 mg Se/kg of soil increased growth and yield in all three cultivars, but 5 and 10 mg Se/kg of soil without sulfur, caused toxicity symptoms, white spots on leaf margins, while its toxicity decreased when 50 and 100 mg S/kg of soil was used and toxicity disappeared by using 150 mg S/kg of soil. This indicates that low levels of Se may have positive effects on growth and yield of wheat through meaningful interaction between Se and sulfur

Enhanced Sorption of Cadmium by using Biochar Nanoparticles from Ball Milling in a Sandy Soil

Two sizes of particles have been employed from wood-derived biochar which produced by slow pyrolysis at 650°C under Ar gas flow to investigate size and dosage effects of biochar at cadmium (Cd) sorption via batch experiment in a sandy soil. The macro (MBC) (0.5–1 mm) and nano size (NBC) of biochar divided by sieving and milling by planetary ball mill processes from pristine biochar, respectively. X-ray diffraction analysis of NBC indicated the presence of magnesian-calcite mineral with turbostratic crystallites. Also, NBC differs from MBC by a higher intensity and different types of surface functional groups such as hydroxyl and carboxyl, and by more polarity, aromaticity and less C–C bands based on FTIR analysis. The zeta potential of NBC ranged from +16.2 to –71.8 mV which can be an effective factor in the agglomeration of particles. NBC particles have a higher specific surface area (approximately 210%) and total pore volume and external surface area, and greater mean pore diameter than MBC. Isotherm equations, namely, Freundlich, Langmuir, Temkin, and Dubinin–Radushkevich were applied to evaluate which model provides the best fit predicted data with experimental results. The Langmuir isotherm provided the best fit according to adjusted R2 and reduced chi-square parameters. By adding 2% (w/w) of MBC and NBC to sandy soil samples, maximum sorption of cadmium reached 328.9 and 1062.4 mg kg–1 which were 58.6% and 412.2% more than control soil. The findings of the study confirmed that ball milling proposes nanobiochar which is more effective at cadmium sorption from contaminated solutions

Domain Extension for Enhanced Target Collision-Resistant Hash Functions

Abstract. We answer the question of Reyhanitabar et al. from FSE’09 of constructing a domain extension scheme for enhanced target collisionresistant(eTCR)hashfunctionswithsublinearkeyexpansion.TheeTCR property, introduced by Halevi and Krawczyk [HK06], is a natural fit for hash-and-sign signature schemes, offering an attractive alternative to collision-resistant hash functions. We prove a new composition theorem for eTCR, and demonstrate that eTCR compression functions exist if and only if one-way functions do.

Boosting Authenticated Encryption Robustness with Minimal Modifications

Secure and highly efficient authenticated encryption (AE) algorithms which achieve data confidentiality and authenticity in the symmetric-key setting have existed for well over a decade. By all conventional measures, AES-OCB seems to be the AE algorithm of choice on any platform with AES-NI: it has a proof showing it is secure assuming AES is, and it is one of the fastest out of all such algorithms. However, algorithms such as AES-GCM and ChaCha20+Poly1305 have seen more widespread adoption, even though they will likely never outperform AES-OCB on platforms with AES-NI. Given the fact that changing algorithms is a long and costly process, some have set out to maximize the security that can be achieved with the already deployed algorithms, without sacrificing efficiency: ChaCha20+Poly1305 already improves over GCM in how it authenticates, GCM-SIV uses GCM’s underlying components to provide nonce misuse resistance, and TLS1.3 introduces a randomized nonce in order to improve GCM’s multi-user security. We continue this line of work by looking more closely at GCM and ChaCha20+Poly1305 to see what robustness they already provide over algorithms such as OCB, and whether minor variants of the algorithms can be used for applications where defense in depth is critical. We formalize and illustrate how GCM and ChaCha20+Poly1305 offer varying degrees of resilience to nonce misuse, as they can recover quickly from repeated nonces, as opposed to OCB, which loses all security. More surprisingly, by introducing minor tweaks such as an additional XOR, we can create a GCM variant which provides security even when unverified plaintext is released