جستجوی مقالات مرتبط با کلیدواژه « ph » در نشریات گروه « کشاورزی »

The research projects conducted in the field of biogas shows that the type of reactor and the composition of different animal wastes have a direct effect on the amount of biogas extraction. Therefore, the main goal of this research is to design and build a multi-bed reactor with a new capability and investigate the effect of the combination of livestock and poultry waste on the gas production process. For this purpose, a multi-bed cylindrical reactor equipped with a separate stirrer for each bed was designed and built, and the effect of different combinations of livestock and poultry wastes in three levels including 60% by weight of chicken waste and 40% by weight of cow waste, 50% by weight of chicken waste and 50% by weight of cow waste, and finally 40% by weight of chicken waste and 60% by weight of cow waste. , the compound concentration at two levels of TS=10% and TS=15% and the reactor temperature at two levels of 37 and 40 degrees Celsius were examined on the pH and percentage of extracted biogas. The results showed that the use of a bed stirrer in this type of reactor increased the volume of produced gas by 17%. Increasing the ratio of animal waste to poultry, balanced the acidity of the environment and finally increased the percentage of extracted biogas. Diluting the composition from TS=15% to TS=10% led to an increase in the pH level and approaching the neutral environment. Also, reducing the temperature of the reactor from 40°C to 37°C increased the percentage of extracted biogas by 8%.

Disinfection of agricultural products as one of the main stages of processing agricultural products has been a very important issue in recent years. One of the new methods of disinfection with high efficiency and low operating costs and at the same time with minimal side effects is using liquid treated with plasma. Plasma-activated water (PAW) and its disinfecting effect on crops have previously been evaluated in a defined volume and for a predetermined amount of time in previous systems. In the current work the physical properties of continuously producing activated water with plasma were studied. The effect of different water sources including tap water (TW), distilled water (DiW), and deionized water (DeW), different water flow rates (0.5, 1, and 2 ml/min), and different sources of gases including air (Ai) and argon (Ar) as a cold-plasma micro jet was studied on physical properties of water at different times. As a result of plasma treatment, the oxidation-reduction potential (ORP), electrical conductivity (EC) significantly elevated while pH showed a significant reduction. There was a significant and positive correlation between ORP and EC, on the contrary pH had a significant and negative correlation with ORP and EC. Our findings showed that deionized water, argon gas, and 0.5 ml ml/min water flow rate are the best combination to produce PAW.

Gene transfer by the Agrobacterium tumefaciens is one of the well-known methods for the production of the transgenic plants. The success rate of this method depends on the growth of the bacteria and the regeneration of the plant explants. Among these variables, the antibiotics functioning as bacterial growth regulators have mainly inhibitory effects on the plant growth. Therefore, the introduction of a successful gene transfer method which is mediated by Agrobacterium requires the identification of an antibiotic with an inhibitory effect on the growth of the bacteria and also has a minimal effect on the regeneration of the explants and the growth of the transgenic plants. In this regard, the present research was conducted with the aim of optimizing the antibiotic used in co-culture in order to increase the transgenic yield of Petunia hybrida. For this purpose, a variety of antibiotics in different concentrations were tested.

The growth rate of A. tumefaciens in the different medium culture with two suitable pH for the bacterial growth (7) and plant growth (5.7) in the presence of 500 mg/L of the cefotaxime antibiotic as a common antibiotic for controlling bacterial growth was investigated. Sensitivity tests were run. The second experiment was conducted to investigate the effect of five different antibiotics in three concentration on the regeneration of the petunia leaf explants.

The results of the bacterial sensitivity test showed that the type and concentration of salt and the pH of the medium culture significantly affect the growth rate of the bacteria. So that the highest rate of bacterial growth was observed in LB and MH medium culture at pH=7, but on the contrary, no growth was observed in MS medium culture. In addition, two antibiotics of cefotaxime and ceftriaxone at 700 mg/L concentration had the highest inhibitory effect on the bacterial growth. The results of this experiment showed that different antibiotics have different effects on the regeneration of explants and the growth of the seedlings. According to the results, the highest volume of callus and also the highest percentage of regeneration were observed in the presence of ceftizoxime and coamoxiclav antibiotics in all three concentrations and cefepime at 300 mg/L. The highest number of the seedlings was also observed in the treatment of ceftizoxime at concentrations of 300 and 500 mg/L with an average of 7.70 seedlings. In relation to the seedling growth traits, the highest number and length of root per seedling were observed in ceftizoxime at 300 mg/l and cefotaxime at the same concentration, respectively. The highest dry weight belonged to the grown seedlings in the presence of co-amoxiclav antibiotic followed by the ceftizoxime (300 mg/L).

 The overall results of these experiments show that the seedlings which are grown in the presence of ceftizoxime antibiotic had a good growth rate, while the use of this antibiotic was effective in inhibiting the growth of A. tumefaciens. Therefore, we recommend that the use of ceftizoxime antibiotic in the co-culture process will be effective in increasing the efficiency of the gene transfer. Further studies will solidify these results.

Ongoing drought and population growth, the use of treated wastewater for various purposes has become essential. On the other hand, the removal of nitrogen and phosphorus from wastewater is of paramount importancet. In this study, woodchips of Prosopis Juliflora trees, zeolite, and woodchips of Tamarix tress woodchips were used for pollutant removal. Four laboratory-scale reactors were employed to compare the performance of these materials in the removal of nitrates and phosphates from wastewater effluent. The main experimental treatments included a reactor filled with a combination of woodchips of Prosopis Juliflora trees and zeolite (PWZ), a reactor filled with woodchips of Prosopis Juliflora trees (CPW), a reactor filled with woodchips of Tamarix tress (TW), and a reactor filled with a combination of woodchips of Prosopis Juliflora trees, zeolite, and woodchips of Tamarix tress (PWZTW). Each of these treatments was tested at three hydraulic retention times of 12, 18, and 24 hours to investigate the influence of the mentioned filter media on pH, nitrate levels, and orthophosphate levels in the effluent. The average nitrate removal efficiencies in the PWZ, CPW, TW, and PWZTW treatments, across all three retention times, were found to be 82.72%, 72.93%, 76.61%, and 81.12%, respectively. The highest nitrate removal efficiency was achieved in the PWZ treatment , The average orthophosphate removal efficiencies in the mentioned treatments were calculated as 84.04%, 77.46%, 63.94%, and 81.60%, respectively. Overall, the use of a combination of woodchips and zeolite as an amendment improved the removal efficiency of nitrates and phosphates.

One of the solutions to sustainable agriculture is the use of mushroom substrate compost (MSC). Mushroom substrate compost is a mixture of stable organic matter and composed of various components such as wheat straw, poultry manure and gypsum. It is rich in nutrients, such as nitrogen, ammonium nitrate, superphosphate, potassium salts and etc. MSC could be a good alternative for other fertilizers and amendments due to less cost and improving soil properties. However, its simultaneous effect in three levels of 0, 3 and 6 % on the properties of soils with different textures has not been before reported. Therefore, objective of this study was to evaluate the short-term effect of the MSC on some physical and chemical properties of soil with different textures.

In this study, three soil samples with different textures, sandy loam, loam and clay, were taken from a bayer farm of the Agricultural Research Center, Abbas Abad Farm of the Bu-Ali Sina University and a bayer farm in the Kerk Suffla Village of Nahavand County, respectively. Sampling was done with a knowledge of soil properties, from soil surface layer (0-20 cm depth). The soil samples were transferred to the Soil Physics Laboratory of the Bu-Ali Sina University for testing and after being air dried, they were passed through a 4 mm sieve. The research was conducted as a factorial experiment in a completely randomized design with three replications. The factors were included soil texture at three levels (sandy loam, loam and clay), and MSC at three levels (0, 3 and 6% W/W). The MSC sample was obtained from Alvand Mountain Company in Hamadan Industrial City. The mushroom substrate consisted of wheat straw, lime and poultry manure, which were mixed at rates of 57, 36 and 7%, respectively. MSC levels were calculated based on treatments after determining the desired soil content for each container. The treated soils were transferred into plastic containers with dimensions of 21 × 13.5 ×12.5 cm based on the field bulk density of each soil. A total of 27 plastic containers containing treatments were prepared. Soils treated in plastic containers were saturated with tap water and then dried for a 120-day incubation period.

The results showed that the order of the soil total porosity was loam > clay > sandy loam, with significant difference between them. The application of mushroom substrate compost significantly increased the porosity at 3 and 6% levels compared to the control. But there was no significant difference between total porosity at 3 and 6% levels. Also, the order of the bulk density in different textures was exactly opposite to that of total porosity. Application of 6% mushroom substrate compost significantly increased cation exchange capacity in sandy loam soil compared to that in the control and 3% level, but no significant difference was found between the cation exchange capacity of control and 3% level. The order of cation exchange capacity was clay > loam > sandy loam, with significant difference between them. Comparison of the electrical conductivity of the soils at different levels of MSC showed that at the zero level of the MSC, the order of electrical conductivity values was loamy > clay> sandy loam, with significant difference between them. The order of pH values was sandy loam > clay > loam at control. The order of pH values was sandy loam = clay > loam at the 3 and 6% levels of the MSC. The results showed that, soil cation exchange capacity, electrical conductivity and total porosity increased in the ranges from 11.8 to 36 cmolc kg-1, 0.16 to 0.69 dS m-1 and 0.52 to 0.56, respectively and bulk density and pH decreased in the ranges from 1.24 to 1.18 g cm-3 and 8.25 to 7.3, respectively, by using MSC. The greatest effect of treatments at the 6% level of MSC on the electrical conductivity, total porosity, and bulk density was obtained in the soil with loam texture, and on the pH and cation exchange capacity was obtained in soil with clay texture.

According to the results, mushroom substrate compost increased cation exchange capacity, electrical conductivity and total porosity and decreased pH and bulk density in all three soils by increasing MSC levels. Overall, the results showed that mushroom substrate compost improved soil physical and chemical properties, due to its stable organic matter and low bulk density. As this compost has a much lower price than other soil modifiers, therefore, mushroom substrate compost can be used in agricultural lands to maintain soil fertility, improve soil stability, and improve soil physical and chemical properties.

In this study, the effect of changes in pH and molar ratio on the properties of melamine formaldehyde resin for impregnating decorative paper was investigated. The physical properties of the resin such as free formaldehyde, resin shelf life, and the percentage of resin solids contents were investigated in different conditions Also, the molecular structures of resin were studied using FTIR spectroscopy and thermal analysis of resins through TGA. The results showed that a higher pH improved the characteristics of the resin and melamine coating, while increasing the molar ratio of formaldehyde to melamine weakened the characteristics of the resin and coating. In addition, the results showed that the changes observed in the resin caused by The variables of molar ratio and pH have no significant effect on the thermal properties of the resin.

The widely used silver nanoparticles made them readily accessible to the bacteria. The interactions between silver nanoparticles and proteins are still not fully understood. In this research, the effect of silver nanoparticles on glycerol dehydrogenase which is located in the respiratory chain of the Gluconobacter was investigated. Response Surface Methodology and a central composite design were used to evaluate the activity of enzyme and the interactions of pH and temperatures. Enzyme activity was evaluated by colorimetric method. The results showed that increasing the concentration of silver nanoparticles up to 50 mg/L decreased the activity of glycerol dehydrogenase enzyme. The inhibitory effect of nanoparticles decreased beyond this concentration. The glycerol dehydrogenase activity increased 35ºC and pH 7, but the activity decreased thereafter. The parameters of temperature, pH and nanoparticles concentration influenced the activity of glycerol dehydrogenase enzyme independently. It could be concluded that silver nanoparticles decrease the activity of glycerol dehydrogenase, which can ultimately decrease the activity of the respiratory chain and subsequently energy production in Gluconobacter. The results of this research can be used in the targeted control of glycerol dehydrogenase activity to produce dihydroxyacetone.

Mazandaran province is one of the most important rice and citrus-producing areas in Iran, where most of the citrus orchards and agricultural fields are irrigated with groundwater. On the other hand, irrigation water pH is one of the basic qualitative factors that determine the solubility and biological availability of chemical components in the soil such as nutrients and heavy metals, and it can affect agricultural production.

The coastal strip of Mazandaran Province toward the southwest of the Caspian Sea is situated in the north of Iran with an area of 8,252 km2 between 35.77 to 36.99 N latitudes and 50.36 to 57.13 E longitudes. In this study, the temporal and spatial variations of groundwater salinity were studied in the coastal strip using data from 300 wells, collected by Mazandaran Regional Water Company. Data included mean pH for each 6-month period of 9 consecutive years, from 2012 until the end of 2020. pH maps and maps of the risk probability area for rice and citrus growth were obtained by using Ordinary Kriging (OK) and Indicator Kriging (IK) in ArcGIS 10.7.1 software, respectively. Classifications were selected according to the properties pH range for the growth of citrus (5.8, 8) and the optimum pH for rice (6.8) in OK method. The indicator amount of pH was considered equal to 6.8 in IK method. Thereby, areas belonging to different pH classes were outlined and places with the risk probability for growing the rice and citrus were identified.

The 11 different models for semivariograms were drawn, and the best one was chosen according to the lowest nugget-to-sill ratio, and thus Stable and Exponential were obtained as the highest frequency for first and second half-years. The indices of cross validation for each selected semivariogram were estimated within acceptable ranges. In Ik method, the pH of studying area was classified into 4 ranges of <5.8, 5.8–6.8, 6.8–8.0, >8, and the percentage area of each classification derived from the ArcGIS software, the average area of each classification during the studying period was calculated zero, 0.6, 83.5 and 15.9 percent, respectively. It showed that most part of the study area located in the range of 6.8-8. It means most rice fields and citrus orchards were irrigated by the groundwater with the pH close to neutral. The obtained maps in the OK method indicated that the pH of the groundwater was not acidic in any points and alkaline conditions were observed in the western and eastern parts of the province. Therefore, The IK method was used to further investigate and determine the vulnerable areas. The probability of pH risk in rice and citrus growth was classified into 4 ranges (0-20%, 20-40%, 40-60% and 60-100%), and the average percentage area of each classification along the period was estimated 94.9, 4.8, 0.3 and zero percent, respectively. Using the IK method, higher probability of groundwater pH reducing the yield in citrus orchards and rice fields was found in eastern parts of Mazandaran province, which was about 5% of total studying area. Also, the results of the study in these 9 consecutive years did not show any decreasing or increasing trend in pH changes and consequently the area under each classification.

Generally, the results indicated that the pH of groundwater for irrigating the citrus orchards and rice fields was appropriate in the most parts of the province and merely in the eastern part of the province, low water alkalinity may make a risk probability for rice and citrus growth in both western and eastern parts of the province. Due to the fact that alkaline water causes soil alkalinity and consequently reduces the solubility of phosphorus and some other plant nutrients in soil, it is suggested to supply the optimum required fertilization amounts of the nutrients in soil. However, the amount of fertilization should be on the basis of field research results. It is also proposed to study the condition of rice and citrus growth and the irrigated water in more details through the farms of western parts of the province. Due to the fact that most citrus orchards in this province are irrigated under the pressurized irrigation systems and using groundwater for irrigation, it is suggested that the Langelier Saturation Index (LSI) be examined in future research.

This study aimed to compare the effects of combined buffer and sodium bicarbonate on growth performance and ruminal parameters of Holstein young bulls with an average weight of 330.8±43.1 kg and an age of 240 days, fed with a high-concentrate diet. The experiment was conducted for 90 days with 10 days of habituation in a completely randomized design with three dietary treatments and 10 replications, and a forage: concentrate ratio of 20 to 80%. Experimental diets included a control diet (without buffer), a basal diet with 1% sodium bicarbonate, and a basal diet with 1% mixed buffer. Daily feed intake, monthly weight gain, and digestibility were measured. The experimental diets did not affect feed intake, weight changes, and digestibility. The best feed conversion ratio for bulls was in treatment of diet containing the mixed buffer supplement (P<0.05). Daily weight gain was higher in bulls fed with the combined buffer than that of the control group (P<0.05). Rumen ammonia nitrogen was higher in the control group than the bulls receiving mixed buffer (P<0.05). The pH of rumen fluid was lowest in the control group, two hours after feeding (P<0.05). The present study results showed that the mixed buffer had a better performance in controlling the rumen acidity of bulls fed with high concentrate diets compared to sodium bicarbonate, especially in terms of improving feed conversion ratio, and it seems to be necessary to add it to such diets.

Coenzyme Q10, as an antioxidant compound, has a role in the electron transport chain of the animal cell. To study the effects of this natural antioxidant on the quality and composition of the fish carcass; rainbow trout were fed by five dietary treatments containing 0, 25, 50, 100, and 200 mg/Kg of coenzyme Q10 during an 8-week feeding trial. The results showed that coenzyme Q10 increased the pH and decreased the peroxide value of carcass fish on the first day of keeping in the refrigerator. The carcass thiobarbituric acid index was not affected by coenzyme Q10 at different refrigerator storage times (P< 0.05). Dietary levels of coenzyme Q10 significantly improved the organoleptic properties of fish flesh. Feeding the fish with various diet levels of coenzyme Q10 elevated the total omega-3, eicosapentaenoic acid, docosahexaenoic acid, and long-chain polyunsaturated fatty acids in the carcass compared to the control group. Overall, the results of this study showed that using coenzyme Q10 in the levels of 100-200 mg/kg of diet improve rainbow trout carcass quality.

 Considered the habitat of a large number of living organisms, the soil is regarded as one of the most significant resources for fulfilling the essential needs of human beings, whose destruction brings about lots of damage to various aspects of the organisms’ life. As a natural phenomenon occurring in soils with sparse vegetation where the wind blows at high speed, wind erosion is a highly influential contributing factor to soil degradation, covering one-third of the world’s lands. On the other hand, wind erosion-induced detachment of the surface soil and the movement of quicksand causes enormous damage to various aspects of human life.  Meanwhile, arid and desert areas are more subject to the damage incurred by wind erosion and the influx of quicksand. Various methods have already been used to contain wind erosion and prevent its damage, including biological, mechanical, and soil fixation methods. However, in some areas where biological operations are difficult to perform, mulching is initially used to temporarily stabilize the region. In this regard, petroleum mulching has been the most commonly used method in Iran since 50 years ago.  Nonetheless, some experts believe that petroleum mulching increases soil temperature, raises heavy metals and hydrocarbons, intensifies groundwater and environmental pollution, decreases permeability, and inflicts harm on plants and animals. On the contrary, some other scholars argue that not only does petroleum mulching pollute the soil but also increases vegetation, animal population, and consequently the soil’s microbial population by raising the soil’s temperature and increasing its moisture. However, adding petroleum mulch to soil raises concerns about polluting the soil with petroleum materials and altering the soil’s physicochemical properties.

 This study used the soil samples collected in three replications from the 0-5 cm and 5-10 cm depths of both the control area and Hamidiyeh city’s sand dunes, Khuzestan province, that had been mulched for short-term (less than 5 years), medium-term (5-20 years), and long-term (more than 20 years) to investigate the physicochemical properties of the soil. The samples were then transferred to a laboratory where the soil’s physical properties, including the texture, true specific gravity, temperature, and humidity, and its chemical properties, including EC, pH, chlorine, carbonate, bicarbonate, calcium, magnesium, lime, phosphorus, sodium, potassium, and the sodium adsorption ratio were examined and analyzed using the SAS software.

 The results revealed that while petroleum mulching caused significant changes in the soil’s temperature, moisture, chlorine, bicarbonate, potassium, EC, and pH, it exerted no influence on the soil’s texture, calcium, lime, and sodium absorption ratio. It was also found that due to its black color, petroleum mulch absorbs sunlight and increases the soil’s surface temperature, decreasing the soil’s permeability and moisture with its greasy hydrophobic nature. Moreover, the study found that compared to the control area, petroleum mulching increased the amounts of the soil’s EC, bicarbonate, phosphorus, and potassium, and reduced its magnesium, chlorine, true specific gravity, and sodium in some areas. Taking the above-mentioned results into consideration, it could generally be argued that in addition to influencing the soil’s physicochemical properties, petroleum mulching makes significant changes in the moisture, temperature, true specific gravity, pH, EC, bicarbonate, chlorine, potassium, and phosphorus of the soil. Furthermore, the investigation of the effects of petroleum mulching in the region suggested that most of the restrictive changes made in the region occurred during the short term, with the changes turned towards the improvement of the soil’s quality and fertility and the increase in the soil’s temperature by the establishment, improvement, and growth of vegetation over time. Therefore, if mulching does not helps improve vegetation due to the special conditions of the region (for instance, non-exclosure of the region and preserving it throughout the first mulching years), petroleum mulching is not recommended as it increases the temperature, decrease the moisture, and restricts some properties of the soil in the short-term. However, should there be any chances for the improvement of vegetation, petroleum mulching will increase the soil’s quality.

One of the important factors in the use of natural pigments in various foods is their stability and preservation of their antioxidant properties under the production and storage conditions. Astaxanthin is one of these natural pigments that microalgae are one of its resources. In the present study, after the extraction of astaxanthin from hematococcus microalgae (Haematococcus pluvialis) by a combined method (HCL-Acetone), the effect of temperature, pH, and time parameters on its stability and antioxidant activity (DPPH free radical scavenging activity and reducing power of ferric) were evaluated. The results showed that the effect of temperature, pH and time factors alone and the interactions between the time and temperature were significant (p<0.05). However, the interactions of pH with time, pH with temperature, and the interaction of three factors together on the concentration and stability of astaxanthin were not significant (p>0.05). According to the findings, the antioxidant activity and pigment stability at 4 °C was more than 20 °C and with increasing the storage time, these properties were decreased. The pH changes did not have much effect on the pigment properties, although the results at pH=5.5 were relatively better than pH=4.5. Among the studied treatments, DPPH free radical scavenging activity as well as the reducing power of the extracted pigment ranged from 45.5-93.11% and absorption of 0.31-0.81 at 700 nm, respectively. This property makes it possible to use this pigment in food products as an antioxidant. However, use of various methods such as coating the pigment for using in heat-treated foods is recommended due to the low stability of the pigment at the higher temperatures.

The use of biochar as a soil amendment is one of the new methods to improve soil properties and increase plant yield. In this study, in order to evaluate the effect of adding natural biochar on soil properties and yield of Pamirian winterfat (Eurotia ceratoides) plant, an experiment in a completely randomized design were performed with 11 treatments by different levels of biochar (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10% by weight) and three replications in greenhouse conditions. After the end of the growing season, some physical and chemical properties of the soil (pH, EC, organic matter (%), lime, bulk deisty, particle density, and porosity percentage), germination percentage, and yield of E. ceratoides were measured. In all the studied traits of the soil (except for the particle density), and the characteristics of the E. ceratoides plant, the statistical difference between the various levels of biochar was significant (a = 0.01). Adding different levels of biochar increased pH, ECy, soil porosity percentage, soil organic matter, whereas decrased bulk density, lime percentage, clay percentage, sand, and silt.

The import of wooden ice cream sticks to Iran has always been criticized due to the existence of domestic factories. In this study, the type of wood used in imported ice cream sticks to the country was identified and some of their qualitative characteristics were investigated in hope that the results will be used by domestic producers. Classic (flat) and round ice cream sticks were obtained from Daity, Mihan, and Kalleh ice cream manufacturers. The results of wood identification showed that birch is the most used wood in making ice cream sticks, followed by beech. In terms of contact angle, surface roughness, and wood extractives, sticks made from beech wood (round Mihan) were different from other woods, but in sensory evaluation tests, round samples of Mihan and Daity, regardless of their wood type, received the highest scores. According to the results, the optimal properties of woods to be used as ice cream sticks were discussed.