Soil science
M. Mohammadi
Abstract
Introduction Almond (Prunusdulcis Mill.), native to West Asia to the Mediterranean, and Iran after the United States and Spain has a third rank in production of this product in the world. Drought stress is one of the most important factors limiting the yield and production of agricultural products. ...
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Introduction Almond (Prunusdulcis Mill.), native to West Asia to the Mediterranean, and Iran after the United States and Spain has a third rank in production of this product in the world. Drought stress is one of the most important factors limiting the yield and production of agricultural products. Many anatomical, physiological, enzymatic, nutritional, quantitative and qualitative characteristics of almonds are affected by drought stress. There are a lot of micro-organisms in soil can help plant nutrition and uptake of nutrient elements in different ways that can be mentioned by the dual symbiotic relation between micro-organism and plant. Mycorrhizae fungi are one of these microorganisms. The most important beneficial effects of mycorrhizal symbiosis is increasing the nutrient uptake, leaf gas exchange, photosynthesis, water use efficiency, productivity, improve plant nutrition and resistance to environmental stresses. Also, it helps the plant to absorb more water and nutrients by modification of rhizosphere environment, improvement of soil structure through formation of stable aggregates, expansion of external filaments and change of root morphology. The results of mycorrhizae symbiosis research in different plants show that the higher uptake of nitrogen (N), phosphorus (P), potassium (K), iron (Fe), zinc (Zn), copper (Cu) and manganese (Mn). The aim of this study was to evaluate the ability of mycorrhizal fungi, a symbiotic and environmentally friendly agent, in drought stress condition on increasing growth and absorption of water and nutrient elements on almond rootstocks commonly consumed in Chaharmahal-va- Bakhtiari province.Material and Methods This field experiment was carried out as a factorial based on a randomized complete block design (RCBD) with three replications. The treatments consist of two level of mycorrhizal fungus (M0: without and M1 with using of mycorrhizal fungus), four kinds of rootstock (bitter, local Shorab 2, GF and GN) and four levels of drought stress (without stress as a control, slight, moderate and severe water stress which based on ratio of depletion of plant available water). Inoculation of mycorrhizal fungi at the rate of 100 g of a mixture of three species of mycorrhizal fungi (Clariodeoglumus etunicatum, Rhizophagus intraradices and Funneliformiss mosseae) was placed under the roots for each rootstock with a population of at least 100 active fungal organs including spores, vesicles, and hyphae per gram. The plants were exposed to drought stress for six weeks. Leaf samples were taken to measure the amount of nutrient elements. Nitrogen by Kjeldahl method, P by spectrophotometer, K by flame method with flame photometer and nutrients of iron, zinc, manganese, boron and copper were measured by atomic absorption spectrophotometry with an atomic absorption spectrometer (PerkinElmer Analyst 400, Waltham, United States of America). Statistical analysis was done with SAS 9.3 statistical software. Duncan’s multiple range test was used to separate means.Results and Discussion The results revealed that there were significant differences between four cultivars in terms of nutrient concentrations except B. The maximum amounts of the studied characteristics were obtained from GF rootstock. The GN rootstock was in the second ranking. Water deficient treatment showed a significant effect on the examined nutrient elements except Mn and Cu concentrations. The maximum amounts of measured nutrient elements, except K, were obtained from I1 treatment. The highest rate of K was obtained from I3 and I4 treatments. With increasing drought stress the decreasing trend of nutrient elements, except K was observed. Mycorrhizae fungi treatment caused increase of nutrient elements except B. The maximum amounts of N, P, Fe and Zn were obtained from GF +I1. Using of mycorrhizae fungi in drought treatments caused significant increase in N, K, Fe, Mn and B. The maximum amount of nutrients was obtained from GF + M1 treatment. The maximum amounts of N, Fe and B were obtained from I1 + M1 + GN. Inoculation of mycorrhizae fungi caused increase of rootstock growth under drought stress. The change in the shape, volume and number of root branches of the root caused by the consumption of mycorrhizae fungi was due to increased nutrient uptake and changes in the amount of plant hormones such as auxin. Growth and absorption of water and nutrients decreased under water deficient stress. Therefore, the effect of symbiosis with mycorrhizae fungi under water deficient stress conditions was more important than non-stress conditions. This has been reported in the research of various researchers.Conclusion The results of this study showed that with increasing water deficient stress, the amount of nutrient elements decreased except for K. The effectively of GF rootstock to mycorrhizae fungi inoculation was higher due to higher growth potential and root velocity. Nutrients that were measured in inoculated rootstocks were higher than those without inoculation. Under drought stress conditions, the amount of nutrients measured was higher in inoculated rootstocks. Inoculation of mycorrhizal fungi can lead to increase nutrients absorption with some mechanisms such as effective increase in root uptake, root length, number of lateral roots, proton production, and secretion of organic acids, siderophores, chelating compounds, and acid phosphates. Consumption of mycorrhizae fungi increased nutrient uptake and improved almond rootstock resistance to drought stress.
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
