A. Fallah Nosrat Abad; M. Habibi
Abstract
Introduction: According to WHO and FAO studies, the diseases caused by contaminated foods are of the most widespread threats to human health in developing and developed countries. Therefore, in recent years, researchers have been trying to use soil microorganisms to solve this problem and maintain the ...
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Introduction: According to WHO and FAO studies, the diseases caused by contaminated foods are of the most widespread threats to human health in developing and developed countries. Therefore, in recent years, researchers have been trying to use soil microorganisms to solve this problem and maintain the health of plants and the environment. Phosphorus after nitrogen, is a major macronutrient in plants which controls the growth, seeding and fruit production and involves in basic biological functions such as cell division, nucleic acids synthesis, photosynthesis and respiration and energy transfer. However, high amount of soluble inorganic phosphate is annually applied to the soil as chemical fertilizer but a large portion of it is immobilized rapidly after application due to phosphate fixation by aluminum, calcium, iron, magnesium and soil colloids and becomes unavailable to plants. The use of biological agents especially phosphate solubilizing microorganisms, can play an important role in supplying plant nutrients and improves crop health and productivity without causing any harm in agricultural and natural ecosystems. Bacteria and fungi are the two important groups of phosphate solubilizing microorganisms. Phosphate solubilizing bacteria in soil include Rhizobium, Bacillus, Pseudomonas, Agrobacterium, Achromobacter, Enterobacter and Burkholderia, and the most important ones i.e., Bacillus sp. and Pseudomonas flourescens. Material and Methods: In order to evaluate the effect of Thiobacillus, sulfur and phosphorus applicationon population of phosphate solubilizing bacteria in soil, a field experiment was conducted at Zarghan Agricultural and Natural Resources Research Center of Iran in a factorial, based on complete randomized block design with 3 replications. Treatments consisted of three levels of sulfur fertilizer with biofertilizer containing Thiobacillus bacteria (without sulfur and biofertilizer containing Thiobacillus (S0), application of 500 kg S + 10 kg biofertilizer containing Thiobacillus (S1), 1000 kg S + 20 kg biofertilizer containing Thiobacillus (S2) and 2000 kg S + 40 kg biofertilizer containing Thiobacillus (S3) per hectare), three levels of triple super phosphate (without phosphorus (P0), 100% (P1) and 65% (P2) percent phosphorus recommended based on the soil test) in two corn planted and not planted states. After harvesting, 72 soil samples were collected from each plot and transferred to the biology laboratory of soil and water research institute of Karaj. Soil samples were stored in sterile conditions at 4◦C. In order to isolate phosphate solubilizing bacteria, 10 gram of soil from each sample was suspended in 90 ml of sterilized water to make 1:10 dilution. Then, series of dilution were made (101 – 107) and 0.1 ml of suspensions of the diluted soil sample were transferred to petri dishes containing pikovskaya medium and incubated at 28- 30˚C. To identify PSP from halos surrounding characterized colonies was used and counting was performed 1-14 days after cultivation. The colonies were isolated on the basis morphological characteristics such as shape, color and size and then purified by linear culture. Finally, 60 strains were purified that were used to compare phosphate solubilizing capability. Results and Discussion: The results of this study showed that the main and interaction effects of sulfur fertilizer and biofertilizer treatments of Thiobacillus, phosphorus and plants on the population of phosphate-solubilizing bacteria (cells per gram of dry soil) in Pikovskaya medium were significant at 0.01 level probability. The highest population of bacteria was obtained at the lowest level (S1). Increasing the level of sulfur fertilizer and Thiobacillus biofertilizer decreased the population of phosphate-solubilizing bacteria and the highest level of sulfur and Thiobacillus biofertilizer led to the lowest bacterial population. Also, the study of phosphorus application on the bacterial population showed that phosphorus fertilizer at both levels significantly increased the bacterial population compared to the control (no application phosphorus). The best fertilizer treatment for phosphorus application was P1 which had the greatest effect on bacterial population compared to P2 treatment in Pikovskaya environment. In this experiment, the population of bacteria in corn planted conditions was higher than in non-planted conditions and this population increase was observed in almost all different levels of sulfur and phosphorus fertilizers. The highest bacterial population was observed in combined treatment of S1P2 under corn planted conditions. The results of microscopic, physiological and biochemical tests of the strains showed that all 60 bacterial strains were capable to form clear zone in Pikovskaya medium. Among them, 15 strains (7, 3, 2 and 3 strains belonging to Bacillus megaterium, Bacillus subtilis, Bacillus cereus and Pseudomonas fluorescent, respectively) had higher phosphate solubility than the others.
hajar rajabi; A. Fallah Nosrat Abad; Gholamreza bakhshi Khaniki
Abstract
Introduction: sustainable development and the environment are interconnected. Sustainable agriculture is continuous utilization of a farm with respect to various aspects of environmental conditions by using fewer inputs (other than Bio-fertilizers). Phosphorus is one of the essential elements for the ...
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Introduction: sustainable development and the environment are interconnected. Sustainable agriculture is continuous utilization of a farm with respect to various aspects of environmental conditions by using fewer inputs (other than Bio-fertilizers). Phosphorus is one of the essential elements for the plants. Management of soil is possible by using biological fertilizers pillar of sustainable agriculture and providing some of the phosphorus needed by plants via bio-fertilizers. Phosphorus deficiency is extremely effective on the plant growth and productivity. The application of phosphorus fertilizers is expensive and dangerous. In addition, phosphorus in the soilmay become insoluble and will be unavailable to the plants. Studies showed that phosphate solubilizing bacteria in the soil rhizosphere are active and by root exudates solve insoluble phosphates such as tricalcium phosphate, and form absorbable P for plant. Consequently, the use of microbial fertilizers could reduce excessive use of chemical fertilizers and lead to decrease their harmful effects and protect the environment and conservation of available resources. The biological phosphate fertilizer industry uses sugar beet molasses as a binder and drying granules at high temperatures. Therefore, it is important to evaluate the durability of the bacteria in molasses at high temperature.
Materials and Methods: This study was designed as completely randomized design in a factorial arrangement.10 isolates were selected and the ratios of 50%, 25%, 15% and 10% of the apatite, organic matter, sulfur and soluble granule (ratio 1: 1 and 2: 1 bacteria and molasses), respectively, for each isolate was prepared. The final product was dried at 28 and 40 °C and remained for 4 months and population counted at first day and 10, 20, 30, 60, 90 and 120 days after the preparing. The population was counted by the serial dilution technique and cultured at Sperber media.
Results and Discussion:Comparing the average logarithm of population of bacteria in the granules indicated the highest proportion in the granules on the first day and the lowest population on 120 days (4 months), andthe ratio of 1: 1 inoculant and molasses had the largest population than the 2:1. The highest population was observed in 1:1 dried granules at 28 °C, but, some of 1:1 dried granules at 40 °C were consistent with the defined standards. Overall, bacteria I2-4, Z4 and C5-1 showed the greatest amount of population and the population had more power to maintain the standards among the isolates. The granules produced according to the defined standard (two-month period, 105 cell per gram of fertilizer) are dried at 28 °C in both 1: 1 and 2: 1 to the end of 4 months in the standard population. Granules dried at 40 °C for 1: 1 ratio of the population by the end of 4 months in the standard range. In the case of the most isolated granules at the ratio of 2:1 until the end of the second month, the population were within the standard range but at the end of the third month, they come lower than standard except I2-4, Z4 and C5-1. The total population of the granules was as following: Granules 1: 1, 28 °C> 2: 1, 28 °C> 1: 1, 40 °C> 2: 1, 40 °C. Considering to the fact that this standard is undefined for four months, but in this study, the population was 104 granules in the fourth month.
Conclusion: Based on the results, some of these conditions could keep their population and population decline was less. In general, it can be concluded that the granular organic fertilizer phosphorus in the industry of phosphate solubilizing bacteria with sugar beet molasses as a binder and drying at 40 °C can be used The results were positive and the granules can be cited to the production of this type of microbial fertilizer. Considering to the results, it was found that the proportion of molasses and inoculant, drying temperature and storage time were effective on viability of bacteria. Also, instead of using a train of bacteria, phosphate solubilizing bacteria, a combination of any of these bacteria in a field lead to better results. It is clear that by a comprehensive study, the molecular identification of bacteria, and detection of desire genetic loci and then gene transfer between bacteria for increasing of high temperature resistance by spour production and also, gene transfer between bacteria with high population and non-tolerance to sugerbeet molasses and tolerant bacteria to sugar beet molasses but low population; we can achieve bacteria with high population and high tolerance to sugar beet molasses and consequently achieve to favorable results. This result could decrease chemical phosphate fertilizers usage and their harmful effects and help to protect the environment and available resources.
A. Fallah Nosrat Abad; Sh. shariati
Abstract
The high cost of fertilizers in farming systems, soil pollution and degradation of soil are factors that caused to full use of available renewable nutrient sources of plant (organic and biological) with optimal application of fertilizers in order to maintain fertility, structure, biological activity, ...
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The high cost of fertilizers in farming systems, soil pollution and degradation of soil are factors that caused to full use of available renewable nutrient sources of plant (organic and biological) with optimal application of fertilizers in order to maintain fertility, structure, biological activity, exchange capacity and water-holding capacity of the water in soil. Therefore, in recent years, according to investigators biofertilizers and organic farming as an alternative to chemical fertilizers has been drawn. Through this study, we examined the effects of triple superphosphate, organic matters and phosphate solubilizing microorganisms on quantitative and qualitative yield of wheat and nutrient uptake. The experiment was carried out in the factorial based on randomized complete block design. The factors were: 1-phosphate solubilizing bacteria in three levels including control, Pseudomonas Putida and Bacillus Coagulans bacteria, 2- triple superphosphate in five levels of 0, 25%, 50%, 75% and 100% and 3-organic matter in 2 levels of 0 and 15 ton/ha in the soil with high phosphorous accessibility (13 mg/kg soil) but lower than sufficient limit for plant 15 mg/kg soil). The results showed that the highest amount of yield has been recorded in Pseudomonas Putida bacteria treatment with organic matter and 25% phosphate fertilizer. As a result, at the conditions of this experiment phosphate solubilizing bacteria and organic matter significantly had higher yield than control and their combination with phosphate fertilizer had significant effect on reducing phosphate fertilizer use.
A. Gholami; A. Ansouri; H. Abbas dokht; A. Fallah Nosrat Abad
Abstract
Introduction: Sulfur is the key element for higher crops and plays an important role in the formation of proteins, vitamins, and enzymes. It is a constituent of amino acids such as cysteine and methionine, which act for the synthesis of other compounds containing reduced sulfur, such as chlorophyll and ...
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Introduction: Sulfur is the key element for higher crops and plays an important role in the formation of proteins, vitamins, and enzymes. It is a constituent of amino acids such as cysteine and methionine, which act for the synthesis of other compounds containing reduced sulfur, such as chlorophyll and utilization of phosphorus and otheressential nutrients.Deficiency of this nutrient in soil is usually compensated by using chemical fertilizers. However, these fertilizers have harmful effects on the environment and decrease the quality of the agriculture products. Therefore, biological fertilizers are more useful for using in agricultural ecosystems.Sulfurshould be addedto the soil, usually in a reduced form such as elemental sulfur. Use of S oxidizers enhances the rate of natural oxidation of S and speeds up the production of sulfates and makes them available to plants consequently resulting in an increased plant yield. The role of chemolithotrophic bacteria of the genus Thiobacillus through oxidation process in the soil is usually emphasized. Sulfur oxidation is the most important step of sulfur cycle, which improves soil fertility. The result is formation of sulfate, which can be used by the plants, while the acidity produced by oxidation helps to solubilize nutrients in alkaline soils. These bacteria can solubilise the soil minerals through the production of H2SO4 that reacts with these non-soluble minerals and oxidised them to be available nutrients to the cultivated plants. Arbuscular MycorrhizalFungi isan important component ofthe microbiota, mutualistic symbioticsoilfungithatcolonizesthe rootsofmost cropplants.The AM symbiosis involves an about 80% of land plant species and 92% of plant families. They have theability to enhance host uptake of relativelyimmobile nutrientsparticularly phosphorus (P) andzinc (Zn),Manganese (Mn) andiron(Fe).Arbuscular mycorrhizal fungi increased plant uptake of phosphorus, nitrogen and water absorption. Inoculation withthesefungihas increased the yield of numerous field-grown crops.
This study was aimed to evaluate the effects of thiobacillus bacteria and sulfur application on soil pH, and also their interactions with mycorrhizal fungi in order to improve nutrients uptake and grain yield of maize under alkaline soil condition.
Materials and Methods: Treatments arranged as factorial experiment were based on RCBD with three replications. Treatments consisted of mycorrhizal inoculation: inoculated (m1) and non-inoculated (m0), thiobacillus in two levels of inoculated (t1) and non-inoculated (t0) and three levels of sulfur (S0: 0 kg.ha-1, S1: 250 kg.ha-1 and S2: 500 kg.ha-1). Four-row plots were prepared with row width and intra-row space of 60 and 20 cm, respectively. Seeds of maize (Zea Mays, Sc:647) were surface sterilized in a 10% (v/v) solution of hydrogen peroxide for 10 min, were rinsed with sterile distilled water. Before sowing, 300 kg of urea per hectare were applied according to the results of soil analysis. In order to facilitate oxidation of sulfur to sulfate form, , S was applied and thoroughly mixed into top 30 cm of soil 30 days before sowing. One week before sowing, thiobacillus (Thiobacillus thiooxidans) was inoculated. Inoculum of AM fungus Glomus intraradices, were added to soil just before planting at about 2 centimeters below seed sowing dept. To measure Arbuscular Mycorrhizal colonization, root plants collected one week before harvesting, cleared in 10% KOH at 80˚C for 2 h, and then acidified in 1% HCL for 60 min. Then the cleared roots were stained in a solution of Trypan blue. For nutrient analysis, the following procedure was applied. Zn, Fe, S, and P were determined by Inductively Coupled Plasma-atomic emission spectrometry apparatus. For this purpose, ash of seed samples was prepared at 500-550 degree of Celsius and then 5 ml of HCl 37% was added and with dionized water to reach to 50 ml. Kjeldahl method was used to determine nitrogen. Analysis of variance was performed on all experimental data and means were compared using the least Significant Differences (LSD) test with SAS software. The significance level was p>0.05 unless stated otherwise.
Results and Discussion: Results showed sulfur application increased significantly the amount of S, P, N, Fe, Zn, shoot dry weight and leaf chlorophyll of maize. With increasing Sulfur, sulfur concentration in plant shoot increased with linear trend. The highest S concentration was obtained with 200 mg.kg-1 S and the lowest amount was obtained from control plots. Applications of 50, 100, 150 and 200 mg.kg-1 S increased P content about 0.45, 3.91, 4.74 and 5.56 %, respectively. The highest N contentwas obtained with 100 mg.kg-1 S. The thiobacillus significantly increased P, Fe, Zn anddecreased root colonization and soil pH compared to control. Thiobacillus bacteria increased shoot P only with application of 100 mg.kg-1 S. Mycorrhizal inoculation increased the amount of N, P, S, Fe, Zn, shoot dry weight and root colonization. Inoculation with G.intra and G.mosseae increased shoot P content about 4.18 and 3.34% in comparison with the control plots. Single or combination of sulfur and thiobacillus had a negative impact on the root colonization. Based on the results it seems that sulfur, thiobacillus and mycorrhiza in alkaline soils improved crops nutrition and growth. S application and thiobacillus interaction on S concentration of maize shoot were significant. In condition of 0 or 50 mg.kg-1 S application, inoculation of thiobacillus is recommended. Also, the effects of mycorrhiza on P shoot was significant with no application of S.
