نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی کارشناسی ارشد، گروه علوم باغبانی، دانشکده کشاورزی، دانشگاه شهرکرد، چهارمحال و بختیاری، ایران
2 گروه علوم و مهندسی خاک، دانشکده کشاورزی، دانشگاه شهرکرد، شهرکرد، ایران
3 دانشگاه شهرکرد
4 استادیار گروه علوم باغبانی، دانشکده کشاورزی، دانشگاه شهرکرد، چهارمحال و بختیاری، ایران.
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
In order to investigate the effect of growth-promoting bacteria inoculation on soil characteristics, nutrients uptake and growth of bell pepper, a randomized complete block design with five species of growth-promoting bacteria (Bacillus subtilis, Azospirillum lipoferum, Azotobacter chroococcum, Enterobacter cloacae and Pseudomonas putida) with three repetitions was carried out in Isfahan Wheat Field greenhouse in 2021. The chemical and biological properties of the soil, NPK uptake, and the growth and yield characteristics were investigated. The results showed that the addition of growth-promoting bacteria effects on some soil characteristics and bell pepper growth. The treatments showed a significant difference in terms of total nitrogen, phosphorus and potassium available in soil, respiration and rhizospheric microbial population, NK uptake, yield and fruit number (p≤0.01). The best soil nitrogen content (0.44%), nitrogen uptake (28.8 g.m-2) and shoot dry weight (0.565 g.m-2) were observed in Azotobacter chroococcum treatment. The highest rhizospheric microbial population (7.6×106 cfu.g-1) and R/S ratio was 47.9 in Enterobacter cloacae treatment. Fresh weight and dry weight of plant shoot were higher in Azospirillum lipoferum treatment, which was not significantly different from Azotobacter chroococcum and Enterobacter cloacae treatments. In the treatment of Enterobacter cloacae, the yield (18.8 kg.m-2) and the fruits number (65.8/m2) were higher. The application of Enterobacter cloacae, Azotobacter chroococcum and Azospirillum lipoferum bacteria was higher effect on the growth indicators of pepper, which can be recommended for the use of these bacteria as biofertilizers in bell pepper cultivation.
کلیدواژهها [English]
EXTENDED ABSTRACT
Introduction
Plant growth promoting rhizobacteria (PGPR) are associated with plant roots, with metabolism and metabolic processes to increase plant efficacy and augment plant productivity and immunity by reducing fertilizer application rates and nutrient runoff. Studies were conducted to evaluate bell pepper transplants amended with some PGPR isolates in terms of soil characteristics, nutrients uptake and growth.
Methodology
This research was conducted in a greenhouse in Isfahan, in form of a randomized complete block design with three replications in year 1400. The treatments included five genera of growth stimulating bacteria (Bacillus subtilis, Azospirillum lipoferum, Azotobacter chroococcum, Enterobacter cloacae and Pseudomonas putida) and control treatment without microbial inoculation. Chemical and biological properties of the soil, nitrogen, phosphorus and potassium uptake, and growth and fruit yield characteristics were investigated after harvest.
Findings
Results showed that addition of growth-promoting bacteria affects some soil characteristics and bell pepper growth. Treatments showed a significant difference in terms of total nitrogen, available phosphorus and potassium of soil, respiration and microbial population of rhizosphere, nitrogen and potassium uptake, yield and number of fruits (p≤0.01). The best soil nitrogen content (0.44%), nitrogen uptake (28.8 g/m2) and shoot dry weight (0.565 g/m2) were observed in Azotobacter crococcum treatment. Soil basic microbial respiration was higher in Pseudomonas putida treatment (272.4 µg CO2 .g-1.day-1), which showed a significant difference (p≤0.05) with Enterobacter cloacae and control (without inoculation). The highest rhizosphere microbial population and rhizosphere to non-rhizosphere population ratio (R/S) was in Enterobacter cloacae treatment (47.9). The shoot fresh and dry weight of the plant were higher in the Azospirillum treatment, which was not significantly different from the Azotobacter and Enterobacter treatments. Microbial inoculation effect (MIE) in Azospirillum and Azotobacter treatments were higher than the other treatments, which showed a significant difference (p≤0.05) compared to Bacillus subtilis and Pseudomonas treatments. Yield (18.8 kg/m2) and fruits number (65.8/m2) were higher in Enterobacter cloacae treatment.
Conclusion
Results of this study showed that inoculation of plant growth-promoting bacteria has the potential to increase the growth and nutrients uptake of bell pepper and affect biochemical characteristics of cultivated soil. This increase in growth and yield of the plant was positively correlated with the increase in nutrients uptake in plant shoot and to some extent with microbial inoculation effect. The effect of using strains of Enterobacter cloacea, Azotobacter crococcum and Azospirillum lipophrum on growth indicators of bell pepper in greenhouse conditions has been greater than the other strains, which can be recommended as bio-fertilizers in bell pepper cultivation. It is important to evaluate the adaptability of inoculated microorganisms to these culture conditions in order to achieve the maximum benefit from their application. Results of this study can be important in plant healthy and organic production systems.
Keywords: Azotobacter, Enterobacter, Nitrogen uptake, Soil biological properties, Yield.