farnaz rafiei

In tobacco, chemical fertilizers are used to achieve the desired yield like other crops. In recent years, with the aim of maintaining soil fertility, improving physical and chemical properties, and creating a balance in environmental factors, the use of biofertilizers and compounds such as biochar has been considered in line with the goals of sustainable agriculture. Biochar improves soil's physical and chemical properties, increases microbial activity, and provides microorganisms with carbon, energy, and mineral elements. The positive effects of using biochar with some beneficial microorganisms can be intensified. In some studies, the effect of biochar on the abundance of arbuscular mycorrhizal fungi and the positive effects of these in increasing yield have been reported. Mycorrhizal fungi can be considered a suitable solution to improve the plant's nutritional status by absorbing nutrients and more water, decomposing soil organic matter and improving the growth and development of host plants. Mycorrhizal fungi can increase water uptake by entering very small pores that even the plant roots cannot penetrate. Applying other useful soil organisms such as Azotobacter in tobacco fields due to its ability to dissolve phosphates and produce vitamins can improve plant growth and development. Considering that no research has been done in Iran on tobacco production without chemical fertilizers, in this study, the possibility of economic production of tobacco using biofertilizers and modifying compounds such as biochar is evaluated.

This experiment was carried out as a factorial based 3×2×2 on randomized complete block design including biochar (B) at three levels (0, 4, and 8 ton/ha), mycorrhiza (M), and Azotobacter (A) at two levels (without and with application) with four replications. The seedling roots of Azotobacter-containing treatments were inoculated ten days before transplanting. Also, mycorrhiza inoculum was mixed with the soil bed in a ratio of 1 to 10. The biochar was also distributed manually on the surface of the plots and mixed with field soil by a disc. The total weight of four picks of each experimental plot was calculated as fresh yield and after curing as dry plot yield. The leaf nitrogen content was measured by the Kjeldahl method, phosphorus was measured by spectrophotometer, and the amount of absorbable potassium was measured by reading potassium ions by flame photometer. Phillips and Hayman's (1970) method was used to calculate the mycorrhizal symbiosis of the root. The nicotine and sugar content was determined using the standard method Nos. 35 and 38 of the world organization of Corseta. 

Application of 4 ton/ha biochar increased fresh yield by 11%, cured yield by 12%, the leaf nitrogen, phosphorus, and potassium content by 13, 20, and 15%, respectively, and leaf nicotine and sugar content by 18 and 24% compared to zero level. The leaf nitrogen enhanced by increasing biochar consumption level. The highest amount of leaf nitrogen was obtained at the B8. The same trend was observed in leaf phosphorus content. But in terms of potassium content, the lowest amount was obtained at B0 with 2.6% and the highest at B4 with 3%. Application of mycorrhiza inoculum increased the fresh and dry yield by 6%. The positive results of this study in the simultaneous use of biochar and mycorrhiza and Azotobacter on the mycorrhizal symbiosis can be due to the positive effect of biochar in increasing the activity of other microorganisms such as mycorrhiza or reducing the negative effects of harmful chemical compounds in soil. In this study, although using Azotobacter increased the leaf yield, this increase was not significant. Also, the Azotobacter application had a positive and significant effect on nicotine content and increased it by 32%. The application of Azotobacter can be a desirable solution to increase tobacco nicotine content. 

Due to the lack of significant differences between 4 and 8 tons per hectare of biochar on the evaluated traits in terms of economic aspects, the use of 4 tons per hectare of biochar along with the use of mycorrhiza and Azotobacter to achieve acceptable yield while maintaining chemical quality in tobacco farms is recommended.

Tobacco is cultivated as a valuable crop in more than one hundred countries in different climatic conditions and plays an important role in the economies of some countries.This study was performed to evaluate the effect of mycorrhiza and azotobacter with application of biocahr on tobacco leaf yield, root characteristics and phytochemical components under rainfed conditions for two growing seasons at 2016 and 2017 at the Research Farm of Tirtash Tobacco Research and Education Center of Mazandaran province, Iran. A factorial experiment based on randomized complete block design with four replications and three treatments was performed. Treatments consisted of biochar (B) at three levels (0, 4 and 8 ton/ha), mycorrhiza (M), and azotobacter (A) both at two levels (without and with application). Application of 4 ton/ha biocahr increased fresh yield by 26%, cured yield 26%, root dry weight 44%, root fresh weigth 37%, root length 41%, nicotine 3%, while reduced sugar content 24% and sugar to nicotine ratio by 21% as compared to zero level of biochar application. The effect of mycorrhiza and azotobacter application on tobacco leaf yield but it was not significant, however, azotobacter had the most significant effect on nicotine content (17%). There was a positive and significant correlation between root characteristics and tobacco leaf yield. Due to the lack of significant differences between levels of 4 and 8 tons per hectare of biochar in most of the evaluated traits in terms of economic approach, the use of 4 tons per hectare of biochar along with mycorrhiza and Azotobacter to reduce the adverse of low water effects in rainfed farms and ameliorate the tobacco growth is recommended. Also azotobacter application is considered as desirable factor to increase of nicotine in tobacco.

Water resource limitation in the end of growth season of rapeseed crop is one of the main problems for production and development of this crop in semi-arid regions of Iran. Therefore, introduction of compatible and tolerate cultivar to this condition is crucial for growth expansion of rapeseed. To identify and introduce suitable rapeseed cultivar for delayed planting, a split plot experiment based on randomized complete block design with three replications at Research Field of Seed and Plant Improvement Research Institute of Karaj, Iran was conducted in 2015-16 and 2016-17. In this study, sowing dates were October 7 (normal) and November 6 (delayed planting) asseinged to the main plots, and rapeseed cultivars including ES Hydromel, ES Alonso, ES Darko, ES Lauren and Ahmadi to the sub-plots. To introduce of tolerate cultivar to drought tolerance indices, experimental plots were subjected to two common irrigation conditions (control) and irrigation interruption from the flowering stage onwards (drought stress). Combined analysis of data indicated that delayed planting significantly reduced rapeseed oil percentage and oil yield. According to the results ES Hydromel cultivar produced the highest oil percentage (41.61%) and oil yield (1381.08 kg.ha-1). Based on the selected indices of this study, including geometric mean productivity, stress tolerance index, and mean productivity, the most tolerant cultivar under both normal and delayed planting was ES Hydromel and the least tolerant cultivar under normal conditions was ES Lauren and under stress conditions was ES Darko. The results of cluster analysis also confirmed the formation of two clusters, ES Darko, Ahmadi and ES Lauren in belonged to sensitive cluster and ES Hydromel and ES Alonso to the tolerant cluster.

This research was accomplished in 2016 at greenhouse for study of effect of different concentrations of seaweed (Sargassum) extract on growth of Menthapiperita. Present research was done in a factorial design with a completely randomized four replications. The factors were different concentrations of seaweed extract with 0, 10, 20, 30 and 40 percent, different spray time in two period types of every 5 and 10 days.Results in this study showed that Sargassum extract concentrations had no positive effects on morphological characteristics including stem high, the number of shoot, number of leaves, number of nodes, fresh and dry weight.In general it can be concluded that, the use of this alga in the production of peppermint because of the decline in growth rates is not recommended and the concentration of the alga more than 20% can be used as herbicide.

In order to investigate the morpho-physiological responses of purslane plant to humic acid under Nickle stress a split plot experiment based on a completely randomized design with two factors and three replications were carried out in the greenhouse. The factors were nickel concentrations with four levels (0, 0.2, 0.4 and 0.6 mM) as the main plots and four levels of humic acid concentrations (0, 200, 400 and 600 mg/L) as sub-main plots. The results showed that different nickel and humic acid concentrations had significant effects on most of morpho-physiological traits such as; root length, MDA, SOD, CAT chlorophyll and carotenoid contents. By increasing nickel levels, the growth indices such as shoot and root length, fresh and dry weight, chlorophyll, a, total chlorophyll and the amount of carotenoid decreased, while by increasing the nickel levels the proline content, MDA and CAT decreased. By increasing humic acid level, the proline content and the activity of CAT increased, while the amount of MDA and SOD enzymes decreased. The highest yield and chlorophyll and carotenoid contents was obtained at 0.4 mM nickel and 600 mg/L humic acid. However, it can be concluded that applying the humic acid can be a suitable procedure to reduce the harmful effects of nickel stress and improving in physiological and biochemical parameters and plant tolerance to nickel stress in Portulaca oleracea.

In this work, the batch removal of Ni ions from aqueous solution and wastewater using marine brown alga Sargassum was investigated. Activated carbon, prepared from Sargassum by acid decomposition, was also used for the removal of Ni from aqueous solution and wastewater. The effects of pH, biosorption time, adsorbent dose, metal ions concentration were considered. The most effective pH was found to be 5.0. The maximum uptake rates for nickel with initial concentrations of 30, 50 and 70 mg/L were obtained to be 97.8% , 84.53% and 60.34% respectively at pH=5. The equilibrium adsorption data were fitted to isotherm models. The adsorption followed second order kinetic. This study shows the application of activated carbon as valuable material for the removal of Ni from aqueous solution and wastewater