Mohammad Jafar Malakouti; A. Majidi; x x
Abstract
Introduction: Among growth factors, proper nutrition plays an important role in increasing yield and the quality of wheat grain. Wheat in most human societies is a strategic product and the main supplier of protein and calories needed by communities. Among growth factors, proper nutrition plays ...
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Introduction: Among growth factors, proper nutrition plays an important role in increasing yield and the quality of wheat grain. Wheat in most human societies is a strategic product and the main supplier of protein and calories needed by communities. Among growth factors, proper nutrition plays an important role in increasing yield and the quality of wheat grain. Potassium (K) is the most abundant cation in the cytoplasm of the plant and plays an important role in plant physiological functions. Its deficiency reduces the qualitative and quantitative yield of crops. It is an essential component in the basic stages of protein biosynthesis. Its deficiency results in a decrease in wheat protein. The results showed that a small amount of potassium was needed in the establishment and wintering stages of wheat and it was highly required at the later stages of plant growth and the plant requirement reached its maximum in flowering stage. This illustrates the importance of taking potassium partition. Among the low nutrient elements, Zinc (Zn) is the most important element that is clearly deficient in calcareous soils. Zinc is essential for enzymatic activities and increases the protein, carbohydrate and gluten of wheat grains.
Materials and Methods: In order to investigate the effect of different sources of potassium (K) fertilizers management on some qualitative and quantitative characteristics of wheat, two experiments were conducted in two fields with lower and higher critical level of K (Kava=125 and Kava= 412mg kg-1) in a randomized complete block design with five treatments and four replications in West Azarbayjan province in 2017-18. Treatments were as follows: T1 = control (use of all essential nutrients based on soil test except K-fertilizer) ; T2 = T1 + whole sulfate of potassium (SOP) before planting; T3 = T1 + consumption of 50% K from (SOP) before planting and 50% from muriate of potassium (MOP) in two topdressing; T4 = T1 + consumption of 50% K from SOP before planting and 50% from soluble sulfate of potassium (SSOP) in two topdressing; T5 = T1 + consumption of 50% K from SOP before planting and 50% from SSOP + Zn-EDTA in two topdressing periods during the first stem elongation and wheat heading. Basal elements based on soil analysis results were as follows: at site one, containing 250 kg ha-1 potassium fertilizer, 150 kg ha-1 triple superphosphate and 100 kg ha-1 pre-planting urea fertilizer, and at site two potassium and urea similar to site one and 75 kg ha-1 triple phosphate. Topdressing 120 kg urea ha-1 was used in two stages i.e. the first stem node and the emergence of cluster at both locations. The size of the plots was 4 m2 and the interval was 2 m. Mihan cultivar was planted at a density of 500 seeds m-2 and 180 kg ha-1 using a linear grain harvesting machine. After determination of yield parameters, soil and plant composite samples were prepared and taken to the laboratory. Physical and chemical analysis of soil was performed using conventional methods at the Soil and Water Research Institute. Statistical analysis of data for different traits at two locations was performed using SAS statistical software version 9.1. Mean comparisons were undertaken using Duncan's multiple range test at the 5% level of probability.
Results and Discussion: The results of this study revealed that in the field (1), K-fertilizers increased grain yield and protein content. In this field, T5 was the best treatment in comparison with the other treatments. Split application of SSOP+Zn-EDTA was the best treatment and increased potassium fertilizer efficiency (KUE). Topdressing of SSOP+Zn-EDTA compared to other K-fertilizers, due to having available K and Zn, increased the kernel, grain yield, grain protein, straw weight and Zn content. While KUE in T2 was 5 kg kg-1, it became 6 kg kg-1 in T3 and T4 , and increased up to 8 kg kg-1 in T5. However, in the field (2) due to its higher content of available K, application of K-fertilizers had no significant effects in all treatments. In the field (1), applying the optimum amount of fertilizer (T3), increased wheat yield by 1300 kg ha-1 compared to the control treatment. However, T5 increased the yield and fertilizer efficiency by 11% and 60%, respectively, even with respect to T3. Therefore, split application of K-fertilizers should be conducted based on the soil analysis result.
Conclusion: Topdressing of soluble sulfate potassium +Zn-EDTA compared to other K-fertilizers, due to having available K, Zn and SO4, increased grain yield, protein, straw weight and Zn content, and fertilizer efficiency.
Maryam Pourmorad; Mohammad Jafar Malakouti; Mohamad Tehrani
Abstract
Introduction: Optimum water consumption in agricultural production is of vital importance as one of the most important environmental factors affecting the growth and development of the plants, especially in arid and semi-arid regions such as Iran. On the other hand, drought stress, among other environmental ...
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Introduction: Optimum water consumption in agricultural production is of vital importance as one of the most important environmental factors affecting the growth and development of the plants, especially in arid and semi-arid regions such as Iran. On the other hand, drought stress, among other environmental stresses, is one of the most important factors that adversely affect the plant growth and yield. Due to the presence of hormonal compounds, organic acids (at low concentrations) can positively affect the production rate and the quality of agricultural products. Considering the water deficit and the necessity of saving water resources as well as the role of organic acids in reducing the negative effects of stress, in the present study attempts are made to investigate the effect of humic and fulvic acid on wheat yield (Triticum aestivum L.) under drought stress conditions.
Materials and Methods: The present study was carried out at the research farm of the national soil and water research institute located 15 km away from Karaj (with elevation of 1280 m) during the 1394-95 crop year. The experiment was a split-plot experiment based on randomized complete block design with three replications which included two main plots (full irrigation and stress) and 36 sub plots of Sivand cultivar. The treatments consisted of the main factor of irrigation regimes at full irrigation and stress levels (35% lower than water requirement) and a sub-factor including six control treatments (F0H0), no foliar application of fulvic acid, in-soil application of 20kg- ha of humic acid (F0H20), Foliar application of fulvic acid (F5H0), and no application of humic acid (F5H0), (F5H20), (F10H0) and treatment (F10H20). The wheat water requirement in the area was estimated by means of Netwat software and irrigation periods were determined based on weather forecast and soil moisture data. Irrigation was carried out using a system of drip irrigation with a specific pressure and discharge level. The stresses were applied from mid-April through consideration of different irrigation hours as compared to full irrigation time. After completion of the growth period, the plant water requirement was accurately estimated by Cropwat software and the percentage of applied stress was accurately calculated (approx. 35%). The Plant yield and some of its components were measured. Statistical analysis was performed through LSD method at 5% significance level using SAS software
Results: The mutual impact between irrigation and fulvic and humic acid applications on total and grain yield was not significant (P <0.05). The highest yield was related to the foliar application of fulvic acid (F10H0) with a total yield of 27331 kg/ha, which had no significant difference with treatment F5H20 (total yield of 25667 kg/ha). Under full irrigation conditions, treatments (F10H0, F5H20) led to 31.81% and 28.44% increase in grain yield (as compared to the treatment yield) respectively. Under low irrigation conditions, treatments (F10H0, F5H20) led to 46.66% and 34.33% increase in grain yield, respectively.
The Weight of 1000 Grains The application of humic acid and fulvic acid alone did not significantly increase the weight of 1000 grains. But the combined application of fulvic acid (F5H0) and humic acid (20 kg /ha) significantly increased the weight of 1000 grains (8.5%). Under low irrigation conditions, the combined application of humic acid and fulvic acid (F10H0) increased the weight of 1000 grains (as compared to the control group) by 14.75%.
Shoot Height The highest shoot height (126.86 cm) was obtained in foliar application of fulvic acid (F5H0) with the in-soil application of humic acid in full irrigation conditions, which increased the shoot height by 22.68% (as compared to the control group). The lowest average shoot height (99.66 cm) was obtained through no application of fulvic acid and humic acid in stress conditions.
Spike Length The application of fulvic acid (F5H0) had no significant effect on spike length. However, the combined application of humic acid (20 kg/ ha-) and fulvic acid (F5H0) increased the mean spike length. Regardless of irrigation conditions, the highest mean spike length was 9.188, 9.105 cm for treatments (F5H20, F10H0) and the lowest mean spike length was 8.258, 8.293 cm, for treatments (F5H0, F0H0).
A number of Grains per Spike The combined application of humic acid and fulvic acid (F5H0) and the application of fulvic acid (F10H0) led to 10% increase in the number of grains per spike as compared to the control group.
Water Use Efficiency The main effect of irrigation and the use of humic acid and fulvic acid on water efficiency was significant at 1% level. The mean comparison at 5% level showed that tension caused 68% increase in water use efficiency. The use of humic acid and fulvic acid increased water use efficiency significantly. The maximum water use efficiency (3.86 kg / m 3) was in spraying the fulvic acid at a concentration of 10 per thousand. Under full irrigation and low water use, the use of fulvic acid at a concentration of 10 per thousand increased water use efficiency as 43.34% and 62.25%
Conclusion: The results of this study showed that the combined application of fulvic acid (F5H0) and humic acid (F5H20) significantly increased all the traits under study. The application of humic acid in drought stress conditions led to 9.09 percent increase in grain yield as compared to the control groups in the full irrigation condition, and the application of humic acid and fulvic acid (F5H0), as well as foliar application of fulvic acid alone (F10H0) under stress conditions led to 23.86% and 24.9% improvement in grain yield respectively ( as compared to control treatments under full irrigation conditions) while foliar application of fulvic acid (F10H0) in drought stress conditions resulted in a 2.65% reduction in grain yield as compared to the same treatment under full irrigation conditions. The results showed that the application of fulvic and humic acid in low irrigation conditions can increase wheat yield and water use efficiency.
Sareh Nezami; Mohammad Jafar Malakouti
Abstract
Introduction: Phosphorus (P) and zinc (Zn) fixation by soil minerals and their precipitation is one of the major constraints for crop production in calcareous soils. Recent Studies show that root exudates are effective for the extraction of the large amounts of nutrients in calcareous soils. A part of ...
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Introduction: Phosphorus (P) and zinc (Zn) fixation by soil minerals and their precipitation is one of the major constraints for crop production in calcareous soils. Recent Studies show that root exudates are effective for the extraction of the large amounts of nutrients in calcareous soils. A part of the root exudations are Low Molecular Weight Organic Acids (LMWOAs). LMWOAs are involved in the nutrients availability and uptake by plants, nutrients detoxification, minerals weathering and microbial proliferation in the soil. At nutrients deficiency conditions citric and oxalic acids are released by plants root in large quantities and increase nutrient solubility like P, Zn, Fe, Mn and Cu in the rhizosphere. These components are the large portion of the carbon source in the soil after exudations are mineralized by microorganisms, quickly. In addition, soil surface sorption can affect their half-life and other behaviors in the soil. In order to study the effect of oxalic and citric organic acids on the extraction of phosphorus and zinc from a calcareous soil, an experiment was conducted.
Materials and Methods: Studied soil was calcareous and had P and Zn deficiency. Soil sample was collected from A horizon (0-30 cm) of Damavand region. 3 g of dried soil sample was extracted with 30 ml of oxalic and citric acids extraction solutions at different concentrations (0.1, 1 and 10 mM) and different time periods (10, 60, 180 and 360 minutes) on an orbital shaker at 200 rev min-1.The soil extracts then centrifuged for 10 minutes (16000g). After filtering, the pH of the extractions was recorded and then phosphorus, calcium and zinc amounts were determined. Soil extraction with distilled water was used as control. Each treatment was performed in 3 replications. Statistical analysis was performed with ANOVA test followed by the Bonferroni method significant level adjustments due to multiple comparisons.
Results and Discussion: The results of variance analysis showed that the effect of different concentrations of organic acids at various times on the pH of extractions was significant at 1% level. Low concentrations of organic acids at various times had no effect on the pH of soil extractions compared to control, but organic acids at 10 mM concentration increased the pH of extractions. This high pH amount was related to the organic acid mineralization and consumption of H+ by microorganisms in the soil. The results of variance analysis also showed that the effect of different concentrations of organic acids at various times in the extraction of Ca from the soil was significant at 1% level .Citric acid extracted higher Ca from the soil compared to oxalic acid. The maximum extracted Ca was observed at 10 mM concentration of citric acid at 10 minutes of shaking time. Extracted Ca at 0.1 and 1 mM concentrations of both organic acids was almost the same at all the times. The higher extraction of Ca with citric acid was due to the Ca precipitation as oxalate. The analysis of variance for P showed that the effect of different concentrations of organic acids at various times was significant at the 1% level. Extracted P by oxalic acid was more than citric acid .The highest amount of P was obtained by 10 mM concentration of oxalic acid at 360 minutes. The amounts of extracted P by both organic acids at 0.1 and 1 mM concentrations were similar to control. Citric acid at 10 mM concentration also released lower P compared to other concentrations and control. More P extraction of oxalate than citrate was due to the Ca-oxalate formation and P release from calcium phosphate in calcareous soil. Different concentrations of organic acids at different time periods had no effect on Zn extraction from the soil and the amount of extracted Zn by organic acids was lower than control.
Conclusion: Organic acids at 10 mM concentration were effective in Ca and P extraction from the soil but had no significant effect on the Zn extraction. It seems that organic acid more than 10 mM concentrations is required for Zn extractionfrom from the calcareous soils. The type and concentration of Organic acids, soil type, shaking time and experimental conditions are important factors that affect the obtained results.
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
M.H. Davoodi; R. Rahnemaie; M.J. Malakouti
Abstract
Abstract
Phosphate is an essential element for plants, animals, and human. Mobility and availability of phosphate in the natural systems is controlled by the adsorption-desorption and dissolution-precipitation reactions. Iron (hydr)oxides including goethite play an important role in phosphate adsorption ...
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Abstract
Phosphate is an essential element for plants, animals, and human. Mobility and availability of phosphate in the natural systems is controlled by the adsorption-desorption and dissolution-precipitation reactions. Iron (hydr)oxides including goethite play an important role in phosphate adsorption reactions in soil. Surface area, crystallinity, and morphology of iron (hydr)oxides are the most important characteristics influencing phosphorus adsorption capacity. With respect to the importance of adsorption process in controlling equilibrium concentration of phosphate in soil and other natural systems, in this research phosphate adsorption reactions on goethite was investigated on three samples of goethite differed in surface area over a wide range of pH and initial phosphate concentration. The goethite charging behavior was calculated from acid-base titration in different levels of ionic strength. The experimental data were analyzed with the CD-MUSIC surface complexation model. Titration data revealed pHpzc= 9.1. Experimental data revealed that phosphate adsorption is strongly pH-dependent. Maximum phosphate adsorption was measured at low pH. It was gradually decreased with increasing pH. Adsorption data were successfully described using two inner-sphere surface complexes, i.e . and . The calculated CD values indicated that 0.28 and 0.46 vu charge is transferred to the goethite surface due to the adsorption of and , respectively. Mole fraction calculation showed that and are the dominant surface species at low and high pH, respectively. Furthermore, experimental data and model calculations revealed that surface area influence phosphate adsorption considerably; however the change in the surface area has no measurable effect on the goethite site density. Therefore, the entire experimental data were successfully predicted by using one set of adsorption parameters.
Keywords: Adsorption, Phosphate, Goethite, CD-MUSIC model, Charging behavior
M. Mahmoudi; R. Rahnemaie; A. Eshaghi; M.J. Malakouti; M. Jalali
Abstract
Abstract
Herbicides are the main sources of soil and water pollution in paddy fields. Herbicides mobility to the surface and ground water is a major concern for human health and the environment. It is, therefore, necessary to investigate their fate and their interactions in natural ecosystems. To meet ...
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Abstract
Herbicides are the main sources of soil and water pollution in paddy fields. Herbicides mobility to the surface and ground water is a major concern for human health and the environment. It is, therefore, necessary to investigate their fate and their interactions in natural ecosystems. To meet this purpose, field experiments were conducted to measure kinetic of thiobencarb dissipation in soil and water at Dashtnaz and Gharakhail agricultural research stations, Mazandaran. Also, its adsorption and desorption isotherms were determined in the soil samples. Thiobencarb concentration was monitored in soil and water (soil solution) via sampling during 315 and 60 days periods, respectively. Adsorption isotherms were carried out in equilibrium concentration ranged from 0 to 26 mg L-1. Desorption isotherms were measured in three equilibrium concentrations. The results of field experiments revealed that thiobencarb concentration is declined with time rapidly and reaches to a steady state after approximately 30 days. Experimental data were successfully described using the first order kinetics equation. Thiobencarb half-lives were determined 7 and 10 days in Dashtnaz and Gharakhail water, respectively. In both soils, thiobencarb concentration was strongly varied in early stages of soil sampling. The variations were reduced with discontinuation of irrigation. Similar to water, thiobencarb concentration in soils was gradually decreased with time, and arrived to a relatively constant concentration after about 110 days. First order kinetic equation described correctly the change in thiobencarb dissipation in soils. Thiobencarb half-lives were calculated 93 and 114 days for Dashtnaz and Gharakhail soils, respectively. Adsorption isotherms indicated that thiobencarb is strongly adsorbed on soil particles. Thiobencarb was desorbed very slowly and a strong hysteresis was observed between adsorption and desorption isotherms. Calculations revealed that thiobencarb is a persistence and non-leacher herbicide in the soil, due to its strong adsorption and high hydrophobic coefficient.
Keywords: Water and soil pollution, Thiobencarb, Degradation, Adsorption and desorption isotherms
