Soil science
J. Al-Jomah; A. Halajnia; A. Lakzian; A.R. Astaraei
Abstract
Introduction
Saline soils resulting from natural and/or anthropogenic processes are very diverse and widely distributed under all climates. Soil salinity as a serious environmental problem has negative effects on plant growth and development in arid and semi-arid as well as humid regions. Since increasing ...
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Introduction
Saline soils resulting from natural and/or anthropogenic processes are very diverse and widely distributed under all climates. Soil salinity as a serious environmental problem has negative effects on plant growth and development in arid and semi-arid as well as humid regions. Since increasing global food security is a fundamental goal to feed the growing world population, it is necessary to develop suitable and efficient techniques for the rehabilitation of salt-affected soils and their exploitation. Chemical fertilizers are usually used to provide nutrients required for plant growth in order to increase crop yield, but application of these chemical components has negative environmental effects and reduces the quality of soils and agricultural products. The use of beneficial microorganisms (bacteria and fungi) as fertilizers and biological amendments has a high potential to improve productivity in saline soils. The aim of this study was to investigate the effect of using Acidithiobacillus bacteria along with mycorrhiza on the production of some photosynthetic and biochemical metabolites in maize under salt stress and comparing it with control conditions.
Materials and Methods
To perform this experiment, a surface soil sample was collected from a depth of 30 cm from the campus of Ferdowsi University of Mashhad, and some physical and chemical properties of the soil were measured by usual laboratory methods. To prepare saline soil a mixture of four compounds MgSO4.7H2O, Na2SO4, NaCl, and CaCl2. 2H2O were used. The mycorrhizal fungus (Funneliformis mosseae) and mesophilic Acidithiobacillus bacteria species two types of bacteria, Acidithiobacillus thiooxidans PTCC No: 1692 (DSM 504) and Acidithiobacillus ferrooxidans PTCC No: 1646 (DSM 583), were purchased from Turan Biotechnology Company (Semnan Science and Technology Park) and Iran Microbial Scientific and Industrial Research Center (PTCC), respectively. In this research, the effect of biological treatments including: two levels of mycorrhiza (inoculation and non-inoculation), two levels of salinity (0.96 and 6 d/m) and four levels of Acidithiobacillus control (C), Acidithiobacillus thiooxidans (T), Acidithiobacillus Ferrooxidans (F), Acidithiobacillus thiooxidans and Ferrooxidans (T+F) were compared with each other on some photosynthetic and biochemical characteristics of Zea mays under greenhouse conditions in the form of a completely randomized design with factorial arrangement with three replications. 10 gr of salt mixture (this amount of salt was obtained to reach electrical conductivity of 6 in the pre-experiment) was added to 5 kg of soil and the soil moisture of the pots was kept for one month in the field capacity. Bacterial treatments were inoculated with 30 mL of cell suspension per pot (approximately 107 CFU mL-1). In the simultaneous use of two bacteria, 15 ml of each bacterial cell suspension (15+15) was added to each pot. Single-cross 704 variety of maize was grown in pots and soil moisture was maintained during the growth period in the field capacity by weighing. Chlorophyll a, b and carotenoid, concentrations of flavonoids, anthocyanins and proline and electrical leakage were measured in fresh leaf samples (third leaf on the stem).
Results and Discussion
The results showed that salinity decreased the percentage of root colonization and chlorophyll a and b content in leaves. Salinity decreased chlorophyll a, b and carotenoid in leaves by 27.9, 68.42% and 50%, respectively. Salinity increased proline concentration (42.62%), electrolyte leakage (33.30%), anthocyanins concentration (96.36%) and leaf flavonoids (84.73%) compared to control soil. Inoculation with mycorrhiza compared to no inoculation had a remarkable and significant effect on all investigated parameters in both saline and control soils. In saline soil, mycorrhizal inoculation reduces electrolyte leakage (56.75%) and increases chlorophyll a (2.3 times), chlorophyll b (6.6 times), carotenoid (1.3 times), proline concentration (24.39%), anthocyanins amount (24.07) and flavonoids (20.4%) in the plant. The effect of bacterial treatments on the investigated parameters in plants inoculated with mycorrhiza was greater than non-inoculated treatments. The effectiveness of the simultaneous application of both bacteria was greater than the effect of each of them alone. In saline soil, simultaneous inoculation of mycorrhizae with both bacteria species reduces electrolyte leakage (14.72%) and increases chlorophyll a (39.80%), chlorophyll b (106%), carotenoid (50%), proline concentration (10.12%), the amount of anthocyanins (14.17%) and flavonoids (4.06%) compared to mycorrhiza treatment alone. The results showed that these bacteria can probably be considered as helping mycorrhizal bacteria.
Conclusion
The objective of this study was to examine the impact of simultaneous inoculation of mycorrhizae and Acidithiobacillus bacteria on select photosynthetic and biochemical metabolites of maize subjected to salinity stress conditions. Confirming the results of other studies, the results of this research also showed the clear and distinct effect of mycorrhiza on increasing chlorophyll and producing metabolites effective in increasing plant resistance to salt stress. In addition, the results showed that although the use of each species of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans alone was effective on the measured parameters in both saline and control soils, the simultaneous inoculation of both Acidithiobacillus bacteria species and mycorrhiza had the greatest effect on increasing chlorophyll, production of proline, anthocyanins and flavinoids and reducing electrolyte leakage and as a result, increasing tolerance to salt stress. In other words, these bacteria can be considered as mycorrhiza helper bacteria, whose activity can improve the function of mycorrhiza. On the other hand, mycorrhiza symbiosis may have increased the efficiency of these bacteria by changing the soil conditions and the environment around the roots. However, further greenhouse and field experiments with other plant species are necessary to confirm these findings.
Soil science
H. Auobi; J. Nabati; Ahmad Nezami; M. Kafi
Abstract
Introduction: The excessive use of chemical fertilizers devastates soil fertility and causes different types of environmental pollution. Therefore, using adequate eco-friendly fertilizers in agriculture enhances productivity but has no adverse effect on nature. Recently, there has been reported that ...
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Introduction: The excessive use of chemical fertilizers devastates soil fertility and causes different types of environmental pollution. Therefore, using adequate eco-friendly fertilizers in agriculture enhances productivity but has no adverse effect on nature. Recently, there has been reported that beneficial soil microbes produce some volatile organic compounds, which are beneficial to plants. The amendment of these microbes with locally available organic materials and nanoparticles is currently used to formulate biofertilizers for increasing plant productivity. These bacteria are naturally present in soils, but their population decreases for a long time because of long-term environmental stress, improper use of chemical agents, and the absence of a suitable host plant. Adding these bacteria to the soil, before or during the growing season, increases the growth and production of agricultural products. Since available water is the main growth limiting factor in chickpea cultivation, it is useful to improve nutrition, especially using plant growth-promoting rhizobacteria, for accelerating the growth and development of plants at the end of the season.
Materials and Methods: In order to evaluate the effect of bio-nutrition and seed priming on growth and yield of chickpea genotypes (MCC463, MCC741, ILC8617, ILC72, FLIP02-51C) an experiment was carried in split plots based on Randomized Complete Block Design with three replications in 2019. Experimental factors included nutritional treatments as the main plots and chickpea genotypes as the subplots. Nutritional treatments were 1- seed priming with the use of free-living nitrogen fixing bacteria, phosphorus solubilizing bacteria and potassium solubilizing bacteria (P + BF), 2- free-living nitrogen fixing bacteria, phosphorus solubilizing bacteria and potassium solubilizing bacteria before sowing (BF), 3- seed priming with the application of free-living nitrogen fixing bacteria, phosphorus solubilizing bacteria and potassium solubilizing bacteria with foliar application of amino acid, potassium and silicon during growth stages (P + BF + F), 4- application of free-living nitrogen fixing bacteria, phosphorus solubilizing bacteria and potassium solubilizing bacteria before planting with foliar application of amino acid, potassium and silicon during growth stages (BF + F), and 5- control (without biological and chemical fertilizers). Free-living nitrogen fixing bacteria, phosphorus solubilizing bacteria and potassium solubilizing bacteria were sprayed five liters per hectare on the soil surface before planting with 107 CFU per ml and mixed with soil. Foliar application with amino acid (1:1000) was done in two stages (before flowering and 50% flowering stage), and foliar application with potassium (1:1000) and silicon (1.5:1000) was carried out in the 50% flowering stage.
Results and Discussion: Results showed that the highest concentration of chlorophyll a was obtained for BF and MCC463 with an increase of 3.1 times greater than control. The highest concentration of chlorophyll b was obtained for BF + F and FLIP02-51. The highest green area index was recorded for MCC741 in P + BF. The highest number of pods per plant in MCC463 and FLIP02-51 was observed in BF + F, with 88 and 30% more than the control, respectively. The highest biomass produced was obtained for ILC8617 and BF + F, by 24% higher than the control. ILC72 and MCC463 showed the highest grain yield in P + BF + F treatment, which increased grain yield by 35% and 4% (320 and 50 kg/ha), respectively, with respect to control. MCC741under BF treatment showed a doubled (810 kg/ha) grain yield relative to control. The highest grain yield for P + BF was found in ILC8617 and increased by 28% (340 kg/ha) as compared to control. In this genotype, grain yield in BF + F was also significantly greater than that in the control by 22%, (270 kg/ha). FLIP02-51 grain yield in BF increased by 12% (170 kg/ha) as compared with the control.
Conclusion: In terms of seed yield, ILC72 and MCC463 were more responsive to P + BF + F and ILC8617 and FLIP02-51 in the BF and ILC8617 in P + BF with respect to other treatments. It seems that despite the positive effect of biofertilizer, genetic characteristics of genotypes are influential in plant growth and yield; therefore, it is necessary to select the appropriate genotype for each region so as to make the most utilization of the nutrients and achieve high yield.
S. Ashrafi-Saeidlou; A. Samadi; M.H. Rasouli-Sadaghiani; M. Barin; E. Sepehr
Abstract
Introduction: Potassium (K) is abundant in soil, however, only 1 to 2 % of Potassium is available to plants. Depending on soil type, 90 to 98% of soil K is in the structure of various minerals such as feldspar (orthoclase and microcline) and mica (biotite and muscovite). About 1 to 10 % of soil K, in ...
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Introduction: Potassium (K) is abundant in soil, however, only 1 to 2 % of Potassium is available to plants. Depending on soil type, 90 to 98% of soil K is in the structure of various minerals such as feldspar (orthoclase and microcline) and mica (biotite and muscovite). About 1 to 10 % of soil K, in the form of non-exchangeable K, is trapped between the layers of certain types of clay minerals. The concentration of soluble K, which is directly taken up by plants and microbes in the soil and is exposed to leaching, varies from 2 to 5 mg l-1 in agricultural soils. Imbalanced use of chemical fertilizers, a significant increase of crop yield (depletion of soil soluble K), and the removal of K in the soil system result in a large rate of K fixation in the soil. As a result, K deficiency has been reported in most plants. The annual increase in the price of K fertilizers and the destructive effects of them on the environment have made it necessary to find a solution for the use of indigenous K of soil. The use of biofertilizers containing beneficial microorganisms is one of these strategies. Although K solubilizing bacteria can be an alternative and reliable technology for dissolving insoluble forms of K, lack of awareness among farmers, the slow impact of K biofertilizers on yield, less willingness of researchers to develop K biofertilizers technology and deficiencies of technology in respect to carrier suitability and proper formulation, are the major reasons for why potassium solubilizing microorganisms and K biofertilizers draw low attention.
Material and Methods: The purpose of this study was modeling and evaluating the effects of different vermicompost, phlogopite and sulfur ratios on the solubility and release of K by Pseudomonas fluorescens and indicating the optimized levels of these variables for efficient biofertilizer preparation. 20 experiments were carried out using the response surface methodology (RSM) based on the central composite design and the effect of different values of vermicompost, phlogopite and sulfur variables, in the four coded levels (+α, +1, 0, -1 and -α), was evaluated on K dissolution. The applied vermicompost, phlogopite and sulfur in the experiment were ground and filtered through a 140 mesh sieve and their water holding capacity were determined. According to experimental design, different amounts of mentioned materials were combined and samples were sterilized in autoclave. The required amount of water along with 1 ml of bacterial inoculant were added to the samples. The samples were kept in incubator for 2 months. At the end of experiment, amount of soluble K were measured by the flame photometer.
Results: The analysis of variance (ANOVA) depicted the reliable performance of the central composite predictive model of K dissolution (R2= 0.949 and RMSE=0.8). Based on the results, the interaction of vermicompost with sulfur (p < 0.038) and the interaction of phlogopite with sulfur (p < 0.0083) were relatively high and significant. Sensitivity analysis of the central composite design revealed that the vermicompost (X1), phlogopite (X2) and sulfur (X3) had positive and negative impact on potassium dissolution, respectively. Therefore, when sulfur content increased to 91.70%, K dissolution decreased to around 31.61%. According to the prediction under optimized condition, maximum potassium dissolution was obtained at the presence of 41.78, 24.35 and 10.25% of vermicompost, phlogopite and sulfur, respectively.
Conclusion: The results indicated that the applied fertilizer composition (vermicompost + phlogopite + sulfur) had a desirable impact on Pseudomonas fluorescens solubilizing ability on a laboratory scale. Due to the fact that Iran soils are often calcareous, there are high amounts of insoluble and unavailable nutrients. Under these unsuitable conditions, the application of these nutrients chemical fertilizers cannot reduce deficiencies. Therefore, we must use the ability of efficient microorganisms to dissolve and mobilize soil native elements. A combination of 41.78% vermicompost, 24.35% phlogopite and 10.55% sulfur could create a proper potassium biofertilizer by providing favorable conditions for bacterial activity. Along with solubilizing activities of bacteria, the presence of sulfur reduces soil pH and thereby nutrients availability and stability increase in these soils. Because of its acidity, sulfur has a significant effect on nutrients dissolution such as phosphorus, nitrogen and potassium, and micronutrients. On the other hand, the presence of vermicompost in this fertilizer, while meeting the carbon and energy requirements of bacteria and acting as a suitable carrier, improves the physicochemical properties of the soil, increases the biodiversity of the microbial community and, as a result, promotes the soil quality and health. The evaluation of this fertilizer composition efficiency (using optimal amounts of materials) at the greenhouse and field scales is suggested.
Ladan Heydari; Javad Hamzei; Tahmeineh Ghytasi Ranjbar; Somayeh Bahramian Ragheb; Fatemeh Madineh Khorrami
Abstract
Introduction: Stability of soil aggregates is a result of complex physical, chemical and biological processes in the soil. In many studies, organic matter has been studied as a major factor in formation of aggregates and the effects of symbiosis between mycorrhizal fungi and bacteria largely ignored, ...
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Introduction: Stability of soil aggregates is a result of complex physical, chemical and biological processes in the soil. In many studies, organic matter has been studied as a major factor in formation of aggregates and the effects of symbiosis between mycorrhizal fungi and bacteria largely ignored, however these microorganisms have a great effect in the formation of the aggregates. Plant roots provide a suitable habitat for the activity of many soil microorganisms. In this regard, the symbiosis of plant roots with fungi is one of the most common and long-lived symbiotic relationships that are found in most ecosystems. On the other hand, biological fertilizers can improve soil aggregation through influence the growth of root and plant. Despite the significant effect of fungi and bacteria on the stability of the soil structure, the effect of arbuscular mycorrhizal fungi species Glomus mosseae and Rhizobium species Mesorhizobiumon caesar on the soil structure has been rarely investigated. Therefore, the aim of this study was to evaluate the effect of chickpea inoculation with Rhizobium (Mesorhizobium caesar) and mycorrhizae (Glomus mosseae) on soil structural stability and aggregates size distribution under both greenhouse and field conditions.
Materials and Methods: The present study was conducted as a randomized complete-block design with three replications in both greenhouse and field conditions. The treatments under field condition were mycorrhizal fungus (Glomus mosseae), Rhizobium (Mesorhizobium caesar), mycorrhizae – rhizobium combined treatment and a control (no inoculation). In the greenhouse condition, sterilized mycorrhiza background material and without plant (without inoculation) treatments were also added. Chickpea was planted at both conditions. Soil sampling was carried out after harvesting. The stability of aggregates using wet sieving method and soil organic carbon content were investigated.
Results and Discussion: Greenhouse study results showed that mycorrhizae treatment significantly increased the mean weight diameter of the aggregates by 51.6% and 189.1%, in comparison with the control (without inoculation) and control- without plant (without inoculation), respectively. This treatment increased macro aggregates and decreased the fine aggregates. In the greenhouse condition, soil organic carbon content had a high correlation with the mean weight diameter of the aggregates (R2 = 0.53) and mycorrhizal treatment increased organic carbon content from 0.73% in the control (without plant) to 1.02%. However, the mycorrhizae – rhizobium combined treatment had less effect on the stability of the aggregates than their single effects. The mass of aggregates of 1–2 mm are more sensitive to short-term management. In the greenhouse condition all the three biofertilizer treatments significantly increased the mass of the aggregates of 1-2 mm in comparison with the control treatment without plant (without inoculation). On the other hand, the mean comparison results showed that there was no significant difference between the sterilized mycorrhizal background and the control without plant (without inoculation). This may be due to the lower organic matter content in these two treatments compared to others. In the greenhouse condition, increasing the mass of coarse aggregates of 4-8 mm in diameter indicates the suitability of soil structure. On the other hand, aggregates coarser than 0.25 mm are considered as coarse and stable aggregates. It can be concluded that the application of mycorrhiza and rhizobium increased soil structural stability through the increase of the mass of these classes of the aggregates (2-4 and 4-8 mm), probably by affecting the length and volume of the root and plant yield. Under the field condition, the treatments had no impact on the mass of the aggregates in different size classes.
Conclusion: Bacteria and fungi can be effective factors in improving soil structure through increasing organic carbon in soil. The results of the present study indicated that aggregate stability was affected by biological fertilizer treatments under greenhouse condition so that the treatments containing biofertilizers increased soil aggregate stability and improved the soil structure that was probably due to increasing plant yield and root. Also, the less effect of biofertilizers on the stability of the aggregates and the increase of coarse aggregates under the field condition can be due to the uncontrolled climatic conditions compared to the greenhouse and the short duration of the study. In recent decades, the physical and chemical properties of soils have changed due to the use of chemical inputs in agricultural lands.The use of biological and organic fertilizers is an appropriate solution to these problems. It is recommended further study on the efficacy of other species of mycorrhizal fungi and rhizobium bacteria in improving soil physical and chemical quality, especially at the field scale. Also, considering the implementation of this project in the field condition, it is suggested to study the physical, mechanical and chemical properties of soil in the long term.
Mahdiyeh Leylasi Marand; Mohammad Reza Sarikhani
Abstract
Introduction: Potassium is one of essential elements for plants and it is the most abundant nutrient on soil surface which is important factor on plant growth and development. Factors such as potassium fixation, erosion, run-off and leaching cause reduction in available potassium of soil. Microorganisms ...
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Introduction: Potassium is one of essential elements for plants and it is the most abundant nutrient on soil surface which is important factor on plant growth and development. Factors such as potassium fixation, erosion, run-off and leaching cause reduction in available potassium of soil. Microorganisms especially bacteria play important role in changing unavailable potassium to available form. Hence, such bacteria can be used for increasing available potassium in soil and consequently production and quality of crops. The K- releasing bacteria can be employed as a biofertilizer to provide plant nutrients in a sustainable approach.
Materials and Methods: In this study, 10 bacterial isolates including Enterobacter sp. S16-3, Azotobacter chroococcum 14SP2-1, Pseudomonas sp. 34A-2, Pseudomonas Az-48, Psudomonas Az-8, S11-2 and 36A-2L provided from soil biology laboratory, department of soil science, University of Tabriz, Bacillus sp. 44-1 provided from soil biology laboratory of Gorgan University of Agricultural Sciences and Natural Resources, and S19-1+ S14-3 isolated from Potabarvar biofertilizer produced by Green Biotech Company were used as a potassium biofertilizer. For this purpose, bacterial inoculant prepared in bagasse and perlite carrier was used to inoculate the disinfected seeds of corn (single cross 704). In this research, bacterial treatments were compared with chemical fertilizer treatments including K50 and K100, in these treatments based on soil test, 50% and 100% of fertilizer recommendation were used (equal to 0.115 g and 0.23 g potassium sulfate per pot, respectively). The experiment was conducted based on completely randomized design with three replications. Duration of this study was about 2 months. Parameters measured during growth were stem diameter, height, chlorophyll index and stomatal conductance and after harvesting, wet and dry weight of root, shoot wet and dry weight, total wet and dry weight.
Results and Discussion: The results showed that expect root dry weight, total wet weight and stem diameter, all parameters were significantly affected by the treatments. The highest plant height was observed for fertilizer treatment 50% (100.8 cm) with an increase of 3.5% compared to the negative control. As to bacterial isolates, highest height was measured in Bacillus sp. 44-1 (98.6 cm). Plant height and stem diameters are indicators of vegetative growth, these parameters can thus increase when plant can use soil nutrients more than others. Enterobacter sp. S16-3 had the maximum stem diameter and the lowest height. It can be due to decreased potassium nutrition and auxin and gibberellin transferred from root. The chlorophyll index and stomatal conductance were equal to 9.567 and 0.097, respectively, which were related to A. chroococcum 14SP2-1. These are the factors of photosynthesis parameters. Increase of these factors may be attributed to the hormone balance effects such as cytokinin which can expand root growth and absorbance of nutrients. A. chroococcum is one of plant growth promoting rhizobacteria which can provide more phytohormones and cause improved plant growth. Therefore, photosynthesis activities can be better. The highest wet weight (265.6 g) and shoot dry weight (44.4 g) were found at fertilizer treatments 50% and then 100% fertilizer recommendation, but in regards to bacterial isolates, A. chroococcum 14SP2-1 and Pseudomonas Az-8 had higher values as compared with the control. The maximum root dry weight was observed in Pseudomonas Az-48 (187.2 g). However, the lowest root weight was obtained at 50% fertilizer recommendation. Hence, this can be explained by the root developing types. The highest total dry weight was measured in Enterobacter sp. S16-3 (63.68 g) and Pseudomonas Az-8 and after these bacterial isolates, fertilizer treatments had better condition. Consequently, these bacteria had another effects on plants such phytohormones productions and enzymatic activities that chemical fertilizer did not have such influences. The highest average of shoot potassium content was observed at 100% fertilizer recommendation (1077.3 mg/plant).
Conclusions: The results showed that fertilizer treatments K50 and K100 had better conditions and pots with chemical fertilizer grew more than others in most plants. But some bacterial isolates showed comparable results relative to K50 and K100. These bacteria can affect plants with directly and indirectly mechanisms. Bacterial treatments such as A. chroococcum 14SP2-1 and Pseudomonas Az-8 improved growth parameters through solubilizing potassium and producing phytohormones. Hence, these isolates can be considered for further studies particularly under field condition.
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. i Yadav; Z. Yuosepur
Abstract
Introduction: Soil fertility management is a key factor in achieving sustainable agriculture. Use of organic fertilizers is one of the methods that without environmental harmful effects with improvement of chemical and biological conditions increases soil fertility. Nitroxin contains a collection of ...
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Introduction: Soil fertility management is a key factor in achieving sustainable agriculture. Use of organic fertilizers is one of the methods that without environmental harmful effects with improvement of chemical and biological conditions increases soil fertility. Nitroxin contains a collection of the best strains of nitrogen fixation bacteria of the genus Azospirillum and Azotobacter. These bacteria through atmospheric nitrogen fixation and the balance of macro and microelements needed for plant uptake, stimulate the growth and development of roots and aerial parts of the plant. Phosphate Barvar2 is another bio-fertilizer which contains set of phosphate solubilizing bacteria of different genera Bacillus and Pseudomonas that can change soil insoluble phosphorus into available forms for plants. The purpose of this study was to evaluate some chemical properties of soil and nutrient concentrations in leaves and seeds of sunflower under the influence of chemical and biological form of nitrogen and phosphorus fertilizers to reduce the use of chemical inputs and to improve quality traits in sunflower.
Material and Methods :The experiment was carried out in a split factorial based on RCBD with three replications in a field in Eivanegharb (Ilam province) in summer of 2011. The main plot included four levels of phosphorus and nitrogen chemical fertilizer (0, 33, 66 and 100% of nitrogen and phosphorus fertilizer requirements) and subplot included factorial of Nitroxin bio-fertilizer application with two levels (inoculation and non inoculation) and Phosphate Barvare2 bio fertilizer with two levels (inoculation and non inoculation). Each plot consisted of 5 rows at a distance of 60 cm and a length of 6 m and 20 cm plant spacing. At the time of flowering, leaves were harvested for measurement of nitrogen, phosphorus, potassium, zinc and manganese. After harvesting, the amount of total nitrogen, phosphorus and potassium and pH of the soil and the concentrations of nitrogen, phosphorus, potassium, zinc and manganese seed were measured.
Results and Discussion: The residual soil nitrogen: Based on these results, the effect of any of the factors tested for the residual soil nitrogen was not significant.
The remaining soil phosphorus: With the increased use of chemical fertilizer, soil phosphorus increased so that the maximum (54.5 mg kg-1 soil) and minimum (40 mg kg-1 soil), available soil phosphorus levels were recorded in consumption of 100% of the required fertilizer and control treatments. Nitroxin and Phosphate Barvare2 applications increased percentage of soil phosphorus, i.e. 12.7 and 23.6 %, respectively, compared to no fertilizer application.
The remaining soil potassium: Comparison of mean values showed that the increase in use of nitrogen and phosphorus fertilizer requirements reduced potassium levels in the soil, so that the maximum amount of soil potassium (624.9 mg kg-1 soil) belonged to control chemical fertilizer treatment and the minimum value of this attribute (514.4 mg per kg of soil) was related to the use of 100% chemical fertilizer consumption with no significant difference with use of 66% chemical fertilizers treatment.
Soil pH: Among the experimental factors studied only bio-fertilizer Phosphate Barvar2 had a significant effect on soil pH at 5% probability so that the use of bio-fertilizer Phosphate Barvar2 significantly decreased soil pH.
Leaf nitrogen: By increasing the amount of chemical fertilizer used, leaf nitrogen content increased, so that the maximum amount of leaf nitrogen (2.5%) was observed in the use of 100% chemical fertilizer consumption treatment. However, no significant difference was recorded in the use of 66% chemical fertilizers tratment. The lowest of this trait (2.2%) belonged to control chemical fertilizer treatment without significant difference with use of 33% chemical fertilizers consumption treatment.
Seed nitrogen: Chemical fertilizer and Phosphate Barvar2 had significant effects on the amount of seed nitrogen content. With the increasing use of chemical fertilizers seed nitrogen increased so that the maximum (2.9%) and minimum (2.6%) seed nitrogen content belonged to use 100% of the chemical fertilizer and non-application of fertilizer, respectively. Mean comparison effect of Phosphate Barvar2 inoculation revealed that seed nitrogen increased by 3.7%.
Seed phosphorus: Analysis of variance showed that the amount of seed phosphorus significantly was affected by the treatments, i.e. Nitroxin and Phosphate Barvare2 as well as the interaction of chemical fertilizer and Nitroxin. Application of Phosphate Barvar2 increased the amount of seed phosphorus by 14.8%.
Seed potassium: Increasing application of chemical fertilizer requirement increased seed potassium. Among the 0, 33, 66 and 100% chemical fertilizer application treatments, Phosphate Barvare2 inoculation increased seed potassium by 23.3, 31.2, 31.3 and 11.4%, respectively.
Seed zinc: According to the analysis of variance, effect of bio-fertilizer Phosphate Barvar2 and interaction of Phosphate Barvar2 and chemical fertilizer on the amount of seed zinc were significant different. However, only in 100% chemical fertilizer requirement, Phosphate Barvare2 inoculation showed significant difference in this trait (63.4% increase).
Seed manganese: The results showed that factors of Nitroxin and Phosphate Barvar2 and also the interaction of Phosphate Barvar2 and chemical fertilizer had significant effects on seed manganese content. Sunflower seed inoculation with Nitroxin increased the amount of seed manganese by 37%.
Conclusion: According to the results, the maximum increase in the amount of nutrients studied in leaves and seeds of sunflower and soil was obtained in combined use of chemical and biological fertilizers.
Keywords: Biofertilizer, Chemical Fertilizer, Nitroxin, Phosphate Barvare2, Seed Elements, Sunflower
Abstract
Biofertilizers can be used as complementary in sustainable agriculture. The main target of this study was effects of nitrogen and phosphorus fertilizers and chemical fertilizers on wheat yield and yield components in two soil types. Experimental design as the factorial formed completely randomized design ...
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Biofertilizers can be used as complementary in sustainable agriculture. The main target of this study was effects of nitrogen and phosphorus fertilizers and chemical fertilizers on wheat yield and yield components in two soil types. Experimental design as the factorial formed completely randomized design with three replications was executed. Experiment Factors included two soil types (sandy loam and clay loam) and 9 fertilizer treatments. For the experiment implementation used 100 gram per hectare of Nitrokara (Azorhizobium caulinodans) and Barvar 3 phosphorus (Pseudomonas putida, Strain P13, Pantoea agglomerans, Strain P5 and Pseudomonas putida, Strain MC1) biofertilizers in single and combined forms by method of seed inoculation. The results showed positive effects of clay loam type and inoculation of two biofertilizer types especially in the presence of 50% of chemical fertilizers on shoot dry weight, root dry weight, number of grains per spike, 1000 grain weight and wheat grain yield. The results showed 100% chemical fertilizer and phosphorus biofertilizer in combination with 50 % of chemical fertilizer treatments showed the highest effect in most characteristics and control treatment showed the lowest effect in this characteristics. Nitrokara biofertilizer in combination with 50% of chemical fertilizer had the maximum 1000 grain weight. Phosphorus biofertilizer in combination with 50% of chemical fertilizer on wheat yield and yield components showed a better effect than Nitrokara biofertilizer.The results of this research showed by combining biological and chemical fertilizers can reduce consumption of chemical fertilizers.
