Document Type : Scientific - Research
Authors
1
2. Crop and Horticultural Science Research Department, Ilam Agricultural and Natural Resources Research and Education Center, AREEO, Ilam,Iran.
2
Faculty member, Department of Agriculture, Pyame Noor University. PO.BOX 19395-4697. Tehran. Iran
Abstract
Introduction
Among the nutrients used by the plant for the growth of nitrogen due to its participation in the structure of proteins, amino acids, coenzymes and nucleic acids are the main factors involved in plant growth and fertility. In recent decades, a group of soil bacteria in the rhizosphere has been introduced as plant growth promoting bacteria that have been able to improve crop growth. In addition to the positive effects on soil properties, these bacteria are also economically and environmentally beneficial and are a good alternative to chemical fertilizers. Azotobacter and Azpirillum are the most important growth-promoting bacteria in plants that, in addition to bio-stabilizing nitrogen, produce growth-promoting hormones such as auxin, gibberellin, and cytokines. Become environmental. Growth-promoting bacteria reduce the damage to reactive oxygen species by producing antioxidant activity or modulating the photosynthetic system, protecting the plant from the presence of these reactive oxygen species and preventing damage to the plant. Since accessible water is the main factor limiting growth in rainfed agriculture, so one of the ways to improve nutrition and plant growth is to use plant growth-promoting bacteria. Bacteria that increase plant growth by affecting the plant by improving physiological and biochemical conditions to increase resistance to adverse environmental factors in rainfed agriculture. Therefore, this study was performed with the aim of the role of these bacteria on the physiological activities of new dryland wheat cultivars in Ilam province.
Materials and Methods
In order to investigate the effect of growth-promoting bacteria on root system in wheat under dryland conditions, a field experiment was carried out in factorial arrangment using randomized complete block design with three replications at the farm station of Sarablah Agricultural Research Center during 2019-2020 cropping season. Experimental treatments include different wheat cultivars (Sardari, Karim, Koohdasht and Rijo) and treatment of different fertilizer sources including: control (without fertilizer source), 50% N fertilizer, Azospirillum+50% N fertilizer, Azetobacter+50% N fertilizer, Azospirillum+Azetobacter+50% N fertilizer and 100% N fertilizer. Each experimental plot consisted of eight planting rows with a row spacing of 20 cm and a length of 4 m. Nitrogen fertilizer (120 kg/ha) was applied at planting and stalking stage based on soil test. Phosphorus fertilizer was applied from triple superphosphate source at the recommended rate of 50 kg/ha at planting time. Experimental data were analyzed using SAS statistical program. Comparison of means by Duncan test and graphs were drawn with Excel software.
Results and Discussion
The results of this study showed that the interaction between cultivar×fertilizer sources was significant on root characteristics of dryland wheat, So that the maximum root length (115.6 cm), root volume (13.3 cm3), root surface (137.2 cm2), specific root length (46.9 cm root length/g DW root), specific root mass (0.0045 g of DW roots /cm3 soil volume), root length density (0.214 cm root length/cm3 soil volume), root tissue density (32.4 g root/cm3 soil volume) and root surface area density (127.5 cm2/cm3) was obtained in Rijo cultivar×Azospirillum+Azetobacter+50% N chemical fertilizer compared to control treatment (without fertilizer sources).
Conclusion
The results showed that due to lack of rainfall in most rainfed fields of the province and also due to the positive effect of fertilizer biofertilizer in maintaining soil moisture, improving the physical and chemical quality of soil, to achieve proper grain yield in rainfed conditions of biofertilizer with chemical fertilizer Used nitrogen. In this study, it was observed that in the combined system of biochemical and chemical fertilizers, the rooting system increases so that the maximum root length, root volume, root area, root specific volume, root length density, root tissue density and root surface density was observed from Rijo cultivar×Azospirillum+Azetobacter+50% N chemical fertilizer. Therefore, the results of this study can be concluded that in rainfed conditions where the intensity and fluctuations of rainfall are not predictable, having a strong root system can greatly reduce the harmful effects of water deficit against environmental stresses in the region and cause an acceptable increase in the yield of dryland wheat grain.
Acknowledgements:
This research was derived from a research project that was carried out at Sarablah Agricultural Research Station. Thanks to all the colleagues who accompanied and helped the authors during the implementation of this study.
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