majid forouhar; Reza Khorassani; Amir Fotovat; Hossein Shariatmadari; Kazem Khavazi
Abstract
Introduction: Global warming is strongly linked to the increase in greenhouse gas emissions to the atmosphere. One of the most efficient ways to reduce the amount of atmospheric CO2 is to produce a lot of biomass and convert the biomass into a biochar. Biochar is an organic carbon-rich solid that can ...
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Introduction: Global warming is strongly linked to the increase in greenhouse gas emissions to the atmosphere. One of the most efficient ways to reduce the amount of atmospheric CO2 is to produce a lot of biomass and convert the biomass into a biochar. Biochar is an organic carbon-rich solid that can be obtained from pyrolysis of various organic materials. In other words, biochar can be produced via thermal degradation of many organic materials such as vegetation biomass, animal waste, sewage sludge, etc. in absence or lack of oxygen. Biochar is more resistant to microbial degradation than its feedstock and has a mean resistance time of several decades. In connection with the use of biochar, the most researches have been done in non-fertile and highly weathered soils. The most significant effects of biochar application, have been also observed in strongly acidic soils. In many arid and semi-arid regions of the world, including Iran, the soil organic matter content is low. The lack of organic resources and their instability in the soil are considered as some of the most important challenges in improving soil fertility and plant growth and yield. To improve soil fertility by using insufficient existing organic resources, stabilizing organic matter by converting it into the biochar can be a fundamental strategy. If this strategy is applied in our country with calcareous soils, it is necessary to study the effects of different biochars on calcareous soils from different aspects .In this regard, in the present study, the effect of three types of biochar in a calcareous soil has been investigated in comparison with their feedstock.
Materials and Methods: The effects of three types of biochar and their feedstock in a calcareous soil were investigated in a 6-months period of incubation. A completely randomized design in the form of split plot experiment, was carried out. The main plots were consisted of Control, Municipal Waste Compost (MWC) and its biochar (BMWC), Sewage Sludge (SS) and its biochar (BSS) and Cow Manure (CM) and its biochar (BCW). The sub plots consisted of five sampling times as 10, 30, 60, 120 and 180 days after the beginning of incubation. Application rate of each treatment per kilogram of soil was calculated based on having the same weight of organic carbon content. So that all treatments contained 2.2 grams of organic carbon. After mixing the treatment with soil and adjusting the humidity to the moisture content of the field capacity (FC), they were transferred to the cans (with 3 holes embedded on their doors) and kept at 25°C in the incubator. During the 6-month incubation period, soil moisture was set at FC levels at intervals of two to three days. Sub samples were taken at five times. After air drying the sub samples, the chemical parameters such as EC of 1:2.5 extract, pH of 1:2.5 suspension, available phosphorus (extracted with sodium bicarbonate 0.5N) and available potassium (extracted with ammonium acetate 1N) were measured. After data collection, statistical analysis was performed using SAS software.
Results and Discussion: The soil texture was sandy loam with 21% of clay, 7% of silt and 72% of sand. Soil CaCO3 content and soil organic carbon content was 16% and 0.23% respectively. Available forms of potassium and phosphorous in soil were 76 and 6.3 mg kg-1, respectively. According to the results, under the influence of each treatment, the variation of soil available P, showed a significant increasing trend with the time. Changes in available potassium and soil pH were not significant over the time. Variation of soil salinity with time although showed an increasing trend but was not significant. Comparison of the effects of treatments showed that both biochars and their feedstock could significantly increase the available phosphorus and potassium in soil. In this regard, the effect of biochars was more pronounced than their feedstock. Among the feedstock, ranking for enhancing effect on available P, was SS > CM > MWC and among the biochars, it was BCM > BSS > BMWC. Ranking for enhancing effect on available K, was CM > MWC > SS and BCM > BMWC > BSS among the feedstock and biochars respectively. The increase in available phosphorus and potassium due to the use of biochars were much higher than that of total phosphorus and total potassium added by biochars. The soil pH decreased as a result of the application of each treatment compared to control. In this regard, the significant difference between biochars and their feedstock were not seen. Probable presence of some amounts of pyrogenic carbon with biochars can be one of the reasons for soil pH reduction. Electrical conductivity of 1:2.5 extract of soil was increased by all treatments compared to the control. Except for BSS, two other biochars significantly increased soil salinity more than their feedstock. This increasing effect on soil salinity can be partially due to the existence of some amount of ash accompanied with biochars.
Conclusions: Application of biochars derived from cow manure, sewage sludge or municipal waste compost in this experimental conditions, led to a significant increase in the amount of available phosphorus and potassium in soil compared to control and their feedstock. Therefore, the use of these biochars can have a high potential for reducing the consumption of some chemical fertilizers. From this point of view, the order of the superiority of the coal was as follows: biochar of cow manure > biochar of municipal waste compost> biochar of sewage sludge. The conversion of any of these feedstock to biochar did not have an effect on their potential for soil pH changes. Except for biochar of sewage sludge, in two other biochar, the potential for increasing soil salinity was higher than the feedstock. Considering that the durability of biochar in soil is much higher than that of its feedstock, it is possible to use suitable biochars such as those examined in this study as a great potential for the sustainable improvement of soil fertility and for reducing the use of chemical fertilizers in our country's agriculture. This requires extensive field researches for other soil properties in different soil and water conditions, with different kinds of biochars and crops.
M. Mohammadi; Mohammad Jafar Malakouti; K. Khavazi; F. Rejali; Mohammad Hossein Davoodi
Abstract
Introduction: Use of unbalanced chemical fertilizers especially P, having low absorption efficiency and low solubility compounds with soil components, has resulted in the production and use of bio-fertilizers (17, 23 and 29). Bio-fertilizer is a preservative material consisting of one or several specific ...
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Introduction: Use of unbalanced chemical fertilizers especially P, having low absorption efficiency and low solubility compounds with soil components, has resulted in the production and use of bio-fertilizers (17, 23 and 29). Bio-fertilizer is a preservative material consisting of one or several specific beneficial micro-organisms or their metabolic products used to supply plant nutrients and development of root systems (29). There are a lot of micro-organisms in soil capabling help to plant nutrition and uptake of nutrient elements in different ways that can be mentioned by the dual symbiotic relation between micro-organism and plant. Mycorrhizal fungus and plant growth promoting rhizobacteria (PGPR) such as Azotobacter and Pseudomonas are able to increase uptake of nutrient elements particularly when they are applied with others and hence they increase the yield of different crops (12, 14; 24 and 30). P solubilizing fungus and bacteria facilitate uptake of slowly diffusing nutrient ions such as P, Zn and Cu and increase their availabilities usually by increasing volume of soil exploited by plants, spreading external mycelium, secreting organic acids, production of dehydrogenase and phosphates enzymes and reducing rhizosphere acidity (9, 15, 19, 23 and 26). The main beneficial use of micro-organism is increasing of host plant growth. It can be done with increase of nutrient elements uptake. The main objective of this study was to evaluate the effect of P and Zn bio-fertilizers on yield, yield components and shoot nutrient elements in two cultivars of bean for the first time in the Chaharmahal-va- Bakhtiari province.
Material and Methods: This field experiment was carried out as a factorial in a randomized complete block design (RCBD) with three replications. The treatments of this research consisted of two cultivars of Chiti bean (Talash and Sadri), four levels of P (P0: Control, P1: Chemical fertilizer on the basis of soil test, P2: 50 percent of recommended P + bio-fertilizer (P), and P3: bio-fertilizer (P)), three levels of Zn (Zn0: Control, Zn1: 50 kg ha-1 Zinc sulphate, and Zn3: bio-fertilizer (Zn)). Bio-fertilizer (P) treatment consisted of mycorrhizal and five strains of Azotobacter chroococcum. Bio-fertilizer (Zn) treatment consisted of Pseudomonas aeruginosa strain MPFM and Pseudomonas fluorescent strain 187. Grain inoculation (5%) was done in shadow and after drying, inoculated grains were immediately cultivated. Two g of mycorrhizal fungus was applied at the base of the grain hole just prior to sowing. Chemical fertilizers were applied from TSP at a rate of 100 and 50 kg ha-1 in P1 and P2 respectively, 50 kg ha-1 ZnSO4.7H2O in Zn1 and 50 kg ha-1 urea as a starter before planting. The size of each plot was 3 × 4 meters. Statistical analysis was done with SAS) statistical software. Duncan’s multiple range test was used to separate means.
Results and Discussion: The results revealed that there were significant differences between the two cultivars on seed yield, number of seeds per pod, 100 seed weight and concentrations of nitrogen (N), potassium (K), and Zn, but there was no significant difference between the other parameters. P treatment showed a significant effect on the examined parameters except the number of seeds per pod. The highest content of yield (3446 kg ha-1) was observed in P2 treatment (18.5% seed yield increase). Zinc treatment also had a significant effect on the parameters being studied except the number of seed per pod and manganese (Mn) concentration. The maximum seed yield (3339 kg ha-1) was monitored in Zn1 and Zn2 treatments. The effect of interactions between P and Zn was significant on the number of pods per shrub, 100 seed weight and K concentration, but it was not significant on the other parameters. However the highest content of seed yield (3520 kg ha-1) was obtained from P2Zn1 (32.5% seed yield increase) treatment. Our results were similar to findings of other researchers (1, 3, 12, 15, 17, 26 and 30). They reported that dual inoculation increases plant productivity. In this study, phosphate and Zn bio-fertilizers caused an increase in yield, yield component and shoot nutrient by increasing nutrient uptake, photosynthesis, growth hormones and creating favorable growth conditions. Also results showed that the consume of P fertilizers were decreased (50 percent) with proper integration of chemical and bio-fertilizers. These results correspond with the results of other researchers (17, 22, 23, 24 and 27).
Conclusion: In this research proper integration of bio- and chemical fertilizers was shown to increase yield and yield components with increasing and improving P and other nutrients’ uptake in both bean cultivars. The result also indicated that combining bio and chemical phosphate fertilizers increased the efficiency of phosphate fertilizers by 50 percent. Sadri cultivar is a suitable cultivar for Chaharmahal-va- Bakhtiari province and regions with a similar climate.
Keywords: Phosphorus, Zinc, Mycorrhizal fungi, Bean (Phaseolus vulgaris L.), Insoluble phosphorus and zinc solubilizers
A. Akhgar; K. Khavazi; N. Khakipoor
Abstract
Abstract
The aim of the present research was to isolate plant growth promoting rhizobacteria producing ACC deaminase which was able to alleviate negative effects of salinity on plant growth. 21 composite soil samples and Canola roots were collected from the saline and relatively saline soils of Qom ...
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Abstract
The aim of the present research was to isolate plant growth promoting rhizobacteria producing ACC deaminase which was able to alleviate negative effects of salinity on plant growth. 21 composite soil samples and Canola roots were collected from the saline and relatively saline soils of Qom and Qazvin provinces. 105 strains were selected from the soil rhizosphere of Canola. According to the growing abilities of the strains in the minimum media of DF having ACC, as the only source of nitrogen, it was determined that 14 strains had the ability to produce ACC deaminase. Identification of strain was carried out according to Bergey’s manual criteria. Results indicated that all the strains belonged to the group of fluorescent Pseudomonads. According to the tests, related to strain determination, 14 strains were identified as P. fluorescent. Measuring ACC deaminase activity showed that the activity of this enzyme in the isolated strains differed from 1.43 to 8.17 μmol α-ketobutyrate/mg/hr. Also the isolates produced IAA in TSB medium between 0.8 – 2.17 μmol/ml. In the present study, effect of selected strains on reducing negative effects of salinity on Canola seedlings growth was evaluated under greenhouse conditions. Under salinity stress, all ACC deaminase producing strains were able to increased canola growth parameters containing shoot fresh and dry weight, shoot and root length. Among tested strains, P12 was the most effective. There was a high correlation between root length and dry matter, and the activity of ACC deaminase producing bacteria. Also with increase salinity from 6 to 8 dS/m, shoot fresh weight and stem length were significantly decreased.
Keyword: ACC deaminas, Pseudomonas, Canola, Salinity
.A Sadat; Gh. Savaghebi; F. Rejali; M. Farahbakhsh; K. Khavazi; M. Shirmardi
Abstract
Abstract
The objective of this study was to assess the effects of few arbuscular mycorrhizal fungi and plant growth promoting rhizobacteria on the growth and yield indices of two wheat varieties in a saline soil (EC=10/1 dSm-1). A factorial experiment with completely randomized design with four replications ...
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Abstract
The objective of this study was to assess the effects of few arbuscular mycorrhizal fungi and plant growth promoting rhizobacteria on the growth and yield indices of two wheat varieties in a saline soil (EC=10/1 dSm-1). A factorial experiment with completely randomized design with four replications was conducted to investigate the effects of three levels of fungal inoculation (non inoculation , inoculation with Glomus etunicatum and with Glomus intradices) and four levels of bacterial inoculation (non inoculation, inoculation with P. fluorescens strains 4 , 9, 12) on two wheat varieties (Sistan and Chamran) as tolerant and semi-tolerant to salinity, respectively. Our results showed that the growth and yield indices of two varieties were significantly (P
A.R. Akhgar; K. Khavazi
Abstract
Abstract
In this study a greenhouse experiment was conducted to evaluate the role of ACC deaminase enzyme on alleviation of salinity stress of canola plant. Canola plants were exposed to Pseudomonas fluorescens strain P12 which contains a rhizobacter capable of producing Pseudomonas fluorescens in comparison ...
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Abstract
In this study a greenhouse experiment was conducted to evaluate the role of ACC deaminase enzyme on alleviation of salinity stress of canola plant. Canola plants were exposed to Pseudomonas fluorescens strain P12 which contains a rhizobacter capable of producing Pseudomonas fluorescens in comparison with plants exposed to mutant Pm12 unable to produce the required enzyme. The mutant was chemically produced using Ethyl Methane Sulfonate (EMS). Comparison of wild strain P12 with its mutant Pm12 indicated that under both saline and non-saline conditions, strain P12 significantly enhanced canola growth parameters including shoot fresh and dry weight, root dry weight, shoot length and green area index. In addition, canola plants inoculated with strain P12 absorbed higher rates of sodium, potassium, calcium, and magnesium, which can be attributed to enhanced roots growth. However, comparing strains P12 with Pm12 indicated that the production of ACC deaminase enzyme by P12 enhanced canola salinity tolerance and consequently, its growth.
Keywords: ACC deaminase, Pseudomonas sp., Salinity, Canola
H.R. Zabihi; A.R. Savabeghi; K. Khavazi; A. Ganjeali
Abstract
Abstract
Plant- growth promoting rhizobacteria enhance plant growth and yield directly and or indirectly. A factorial experiment was conducted in greenhouse to determine the efficacy of four strains of Fluorescent Pseudomonas on wheat yield and yield component under saline conditions. the experiment ...
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Abstract
Plant- growth promoting rhizobacteria enhance plant growth and yield directly and or indirectly. A factorial experiment was conducted in greenhouse to determine the efficacy of four strains of Fluorescent Pseudomonas on wheat yield and yield component under saline conditions. the experiment was carried out with the following treatments (non –inoculation control and inoculation with P.fluorescens strain153 P.fluorescens strain169 P.putida strain108 and P.putida strain 4) and four salinity levels (1,4,8 and 12 dS/m) in a completelyrandomized design .A combinationof (NaCl+ CaCl2 +MgCl2 with equal equivalent) dissolved in distilled water and added to soils to meet the desiredsalinity treatments .wheat seeds were inoculated whit strains before planting. During growing period, the pots were irrigated with distilled water to maintain soil moisture around 0.8 FC .before harvest, growth indices including : plantheight, number of tillers and heads and after harvest,dry weight of shoots and grain yield were determined .Results showedthat with increasing salinity level ,grain yield,1000 weight ,number of grain per spick , plant height and biologic yield decreased significantly (P
E. Karimi; A. Lakziyan; K. Khavazi; A. Asgharzadeh
Abstract
Abstract
Genetic evidences have shown that the rhizobium bacteria nodulate the legume plants because of nod, sym and fix genes. Almost all members of rhizobaceae family harbor large plasmids, which are highly variable in number and size. Representative of nif, fix and nod genes have been located on ...
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Abstract
Genetic evidences have shown that the rhizobium bacteria nodulate the legume plants because of nod, sym and fix genes. Almost all members of rhizobaceae family harbor large plasmids, which are highly variable in number and size. Representative of nif, fix and nod genes have been located on the symbiotic plasmids of different rhizobium species. Therefore, the size and numbers of plasmids of bacterial isolates (by the plasmid profile technique) could be used as a diversity index in ecological studies. In this investigation, the diversity of 196 isolates of sinorhizobium sp isolated from Hamada soils was evaluated by using Plasmid profile technique. The results showed that the number of plasmids among all isolates varied from 1 to 4 and totally 13 different plasmids were identified. The size of plasmids varied from 50 to 200 kb. Isolates with 1, 2, 3 and 4 plasmids formed 63, 21, 13 and 2 percentage of the population. Isolates of sinorhizobium with 2 and 3 plasmids were clustered into 8 and 15 groups, respectively, based on plasmid patterns. Four isolates which contained 4 plasmids were grouped in four different clusters and finally all isolates of Sinorhizobium (196) were grouped in 28 different groups.
Key words: Plasmid profiles, Sinorhizobium