Treatment of Cr(VI)-spiked soils using sulfur-based amendments

The objective of this research was to assess the hexavalent chromium (Cr(VI)) reducing efficiency of sulfur-based inorganic agents including calcium polysulfide (CPS), iron sulfide (FeS), pyrite (FeS₂) and sodium sulfide (Na₂S) in three soils. An alkaline soil (soil 1), a neutral soil (soil 2) and a slightly acid soil (soil 3) constituted the investigated soils. The soils were spiked with two levels of Cr(VI) (100 and 500 mg Cr(VI) kg^?1 soil) and incubated at field capacity (FC) for one month. Then, CPS, FeS, FeS₂ and Na₂S were added at 0, 5 and 10 g kg^?1 and the concentrations of exchangeable Cr(VI) were measured after 0.5, 4, 48 and 168 h in a batch experiment. The pH and organic carbon content of the soils played predominant role in Cr(VI) self-reduction by the soil itself. Complete self-reduction of Cr(VI) from soils 1, 2 and 3 was achieved at maximum Cr(VI) levels of 1, 50 and 500 mg kg^?1, respectively. Therefore, the concentration of Cr(VI) should not exceed the given levels in order to ensure that Cr(VI) is not released into the environment from contaminated sites. Moreover, decreasing pH in the alkaline soil caused significant increase of Cr(VI) reducing efficiency. Na₂S, CPS and FeS, in contrast to FeS₂, were efficient Cr(VI) reducing agents in all three soils. For all added amendments the following order of Cr(VI) reducing capacity was observed: Na₂S > CPS > FeS > FeS₂ in soil 1, Na₂S ? CPS ~ FeS > FeS₂ in soil 2 and Na₂S ? FeS > CPS ~ FeS₂ in soil 3.     

Effect of seed and foliar application of nano-zinc oxide,zinc chelate,and zinc sulphate rates on yield and growth of pinto bean (Phaseolus vulgaris) cultivars

Nanofertilizers have received considerable attention due to their increased uptake by plants. Therefore, this study aimed to investigate the effect of zinc oxide (ZnO) nanoparticles and also different zinc (Zn) fertilizers (Zn sulfate, Zn chelate) on vegetative and yield traits of two pinto bean cultivars “KS21191” and “KS21193”. This experiment was a factorial based on completely randomized design with 24 treatments (three fertilizer applications and eight levels of Zn fertilizer). The results showed that twice foliar application compared to seed application and once foliar application improved growth and yield characteristics of both pinto bean cultivars. Also, compared to control treatment, zinc nanofertilizers improved vegetative characteristics (such as plant height, internode length, root and shoot dry, and fresh weight), yield (pods number and seed weight) and quality (zinc content in seed) of both pinto bean cultivars. Among the zinc fertilizer treatments, 0.10% and 0.15% of ZnO nanoparticles were as a superior treatment.     

Effects of vegetation pattern and of biochar and powdery soil amendments on soil loss by wind in a semi-arid region

Dust emission from wind erosion is a widespread phenomenon in arid and semi-arid areas having considerable implications for ecosystems and human well-being. However, few studies have examined the efficiency of biochar amended to soil on wind erosion control. Aimed at studying the effect of biochar on resistance of soils against wind erosion, a wind tunnel experiment was conducted. We tested (a) soils amended with hard waste walnut wood biochar and soft maize cob biochar, and (b) soils amended with powdery waste wood and powdery maize cob, and compared them with (c) non-treated soil, in their susceptibility to wind erosion and also the additional effect of various patterns of vegetation cover. Amending soil with biochar and powdery material did significantly increase their resilience to wind erosion because of increased soil aggregation. In comparison with the non-treated control, the mass flux of un-vegetated soil reduced from 4.42 to 1.86 g m⁻² s⁻¹ for the waste walnut wood biochar, from 4.28 to 1.50 g m⁻² s⁻¹ for maize cob biochar, from 4.11 to 1.44 g m⁻² s⁻¹ for powdery maize cob and from 3.97 to 1.14 g m⁻² s⁻¹ for powdery waste walnut wood. When combining amendments with vegetation, there was still a substantial improvement, though the soil treatments responded differently in terms of soil loss to different vegetation patterns. A single row vegetation pattern had the highest mass flux, while a zigzag vegetation pattern had the lowest. In conclusion, waste wood or maize cobs, whether applied as biochar or as powdery material, are able to fix soil and reduce wind erosion.     

Assessing the Potential of Pomegranate Meal and Potato Waste as New Organic Amendments for Vermicompost

Waste disposal has become one of the greatest global concerns, which has high operational costs and might cause environmental pollution. Due to the lack of the organic matter in most of the Iranian agro-ecosystem, recycling organic waste materials favors the environment by reducing chemical fertilizers as well as improving soil structure and fertility. A vermicomposting system using cow manure (CM), pomegranate meal (PM) + sawdust (S), CM + potato waste (PW), PM + PW, CM + PM, and CM + PM + PW was set up to find a viable alternative raw material for improving physico-chemical properties of vermicompost after 60 days. The amended vermicompost of PM + S and PM + PW markedly improved the electrical conductivity (EC), which were below the EC limit (by 1.01 and 2.27 dS m^?1, respectively), pH (by 7.04 and 6.60, respectively), and water holding capacity (respectively 1.9 and 1.2 times higher than CM). Vermicompost amendment led to significant reduction of organic carbon (OC), but nonetheless, PM + S and PM + PW showed higher OC content in the final product probably due to the higher initial carbon to nitrogen (C:N) ratio, raw material origin, and lower decomposition rate. In regard to nutrient value, the total phosphorus content in the end-product of PM + S and PM + PW was, respectively, 19.3 and 7.9 times higher compared with the final product of CM. Additionally, the amended vermicompost of PM + PW markedly improved total nitrogen content as compared with CM. The findings suggested that the additional amounts of nitrogen and potassium to PM + S and also potassium to PM + PW would improve the physico-chemical properties and fertilization of the final vermicompost considerably higher than CM vermicompost. This amendment has the potential to mitigate the adverse effects of vermicompost of CM, for example, salinity and alkalinity; and chemical fertilizers, for example, soil pollution with heavy metals in phosphate fertilizers, as well as the potential for soil rehabilitation.     

Effect of Different Levels of Glycerol and Cholesterol‐Loaded Cyclodextrin on Cryosurvival of Ram Spermatozoa

This study was conducted to determine the optimum level of glycerol and cholesterol‐loaded cyclodextrin (CLC) in a Tris‐based diluent for cryopreservation of ram spermatozoa. Ram semen was treated with 0, 1.5, 3 or 4.5 mg CLC/120 × 10⁶ cells in Tris‐based diluents containing 3, 5 or 7% glycerol in a factorial arrangement 3 × 4 and frozen in liquid nitrogen vapour. Sperm motility, viability (eosin–nigrosin staining) and functional membrane integrity (hypo‐osmotic swelling test) were assessed immediately after thawing (0 h) and subsequently after 3 and 6 h at 37°C. There was an interaction between CLC and glycerol on the functional membrane integrity (p < 0.05). In the presence of 3% glycerol, the highest functional membrane integrity (32.2%) was found in the spermatozoa treated with 1.5 mg CLC/120 × 10⁶ sperm. Post‐thaw sperm motility was highest in 1.5 mg CLC immediately after thawing (40.5%) and after 3‐h (30.6%) incubation at 37°C (p < 0.05). Viability of spermatozoa was higher in all CLC treatments than in the untreated samples, and it was highest (33.9%) in the spermatozoa treated with 1.5 mg CLC (p < 0.05). These data indicate that the addition of cholesterol to sperm membranes by 1.5 mg CLC/120 × 10⁶ cells may allow the use of a lower concentration of glycerol (3%), which is sufficient to mitigate the detrimental effects of freezing and thawing.     

Effect of predictors of visual preference as characteristics of urban natural landscapes in increasing perceived restorative potential

Current literature on restorative environments generally shows the importance of urban natural landscapes in increasing perceived restorativeness of urban environments. However, little is known about the positive role of visual characteristics of urban natural landscapes in increasing Perceived Restorative Potential (PRP) of urban environments. This study aimed to understand the role of four predictors of visual preference as characteristics of urban natural landscape on the restorativeness of environments. In this study, 120 students from Universiti Putra Malaysia rated 12 colored slides of urban natural landscape scenes for four restorative components (Being away, Fascination, Coherence, and Compatibility), four predictors of visual landscape preference (Coherence, Complexity, Legibility, Mystery) and a criterion variable (PRP). Coherence, however, was considered as a predictor of visual landscape preference since it is not a significant predictor in explaining PRP. Results indicate that Coherence, Complexity, and Mystery positively explained PRP while Legibility did not. Further analysis revealed that the effect of Coherence and Complexity on PRP was fully mediated by the restorative components and Mystery was only partially mediated. The findings indicate that some predictors of visual landscape preference of urban natural landscapes contribute to increasing PRP of urban landscapes. Although Coherence as a restorative component was not a significant predictor of PRP, it contributed toward increasing the restorative potential of urban natural landscapes when considered as a predictor of visual landscape preference. The results of this study can aid city planners, landscape architects and developers with regards to the influence of visual landscape characteristics in increasing the restorative potential of urban environments.     

Effect of Sodium Nitroprusside on Physiological Traits and Grain Yield of Oilseed Rape (Brassica napus L.) Under Different Irrigation Regimes

Drought stress is the main factor limiting the growth and crop yield in most regions; thus, reducing the effects of drought stress is a research priority worldwide. The aim of this experiment was to evaluate the effect of sodium nitroprusside (SNP) on physiological traits and grain yield of oilseed rape under drought stress. Two field experiments with three irrigation levels (I1: full irrigation (control), I2: irrigation cut-off at the beginning of pod development, and I3: irrigation cut-off at the beginning of grain filling) and SNP foliar applications with four levels (0, 100, 200 and 300?μM) were conducted during the 2015–2017 growing seasons. The results indicated that applying 200 and 300?μM of SNP significantly increased antioxidant enzymes, total chlorophyll, and proline at all levels of drought stress in comparison with applying zero and 100?μM of SNP. Moreover, applying SNP increased grain yield via improving the biochemical traits of the plant under stress and non-stress conditions. Comparison results of the average test of two years showed that the application of 200 and 300?μM SNP increased grain yield to 11.2 and 15.1% in control conditions, 33.6 and 36.7% in I2 and 20.9 and 40.6% in I1 compared to the control. Generally, the results indicated that applying SNP reduced the effects of water-deficit stress on oilseed rape.