نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
1 گروه علوم و مهندسی خاک، دانشکده کشاورزی و منابع طبیعی دانشگاه محقق اردبیلی، اردبیل ایران دانشگاه محقق اردبیلی
2 گروه علوم و مهندسی خاک، دانشکده کشاورزی و منابع طبیعی دانشگاه محقق اردبیلی، اردبیل ایران
3 گروه علوم و مهندسی خاک، دانشکده کشاورزی و منابع طبیعی دانشگاه محقق اردبیلی، اردبیل ایران
4 گروه علوم و مهندسی خاک، دانشکده کشاورزی و منابع طبیعی دانشگاه محقق اردبیلی، اردبیل ایران دانشگاه اردبیل
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Background and objectives: The effect of plant growth promoting bacteria on increasing wheat yield has been demonstrated. Nevertheless, the effect of these bacteria on soil biological quality particularly in the stress conditions such as soil salinity was seldom studied. Therefore, the aim of this study was to investigate the effect of these bacteria on improving biological indices of soil under cultivation of wheat and salinity condition.
Materials and methods: In order to investigate the effect of inoculation with plant growth promoting bacteria (PGPB) on some soil biological indices and wheat growth parameters under salinity stress, a factorial experiment was conducted based on completely randomized design with three replications. The factors were salinity at four levels, control, 6, 8 and 10 dS.m-1, inoculation with plant growth promoting bacteria at three level, no-inoculation, and inoculation with Pseudomonas putida and inoculation with Pseudomonas fluoresces. After the growth period, the plant yield parameters such as the root volume, root and shoot fresh and dry weight, were measured. The organic carbon, microbial biomass carbon, respiration and substrate–induced respiration was also determined.
Results: The results showed that the soil biological indices and plant growth parameters significantly decreased as the soil salinity increased; however inoculation with the bacteria significantly increased plant growth parameters. The inoculation with P. fluorescens and P.putida compared to the control (without inoculation) increased root volume by 83% and 25%, root dry weight by 38% and 7%, and root fresh weight by 52% and 50%, in the salinity level of 6 dS.m-1 respectively. The highest microbial biomass carbon (1997 mg Cmic. Kg-1 dry soil) was observed in inoculation with P.putida. Inoculation with P. fluorescens could also increase soil microbial biomass carbon in the control from 987 to 1765 mg Cmic. Kg-1 dry soil. Compared to no-inoculation, inoculation with both bacteria in all salinity levels increased soil basal respiration and substrate-induced respiration.
Conclusion: It could be concluded that the presence of plant growth promoting bacteria not only increased plant growth parameters under salinity stress, but also they improved soil biological indices such as soil microbial biomass carbon, basal respiration, and substrate-induced respiration and thereby indirectly enhanced plant growth conditions and increased plant yield quantity and quality.
Conclusion: It could be concluded that the presence of plant growth promoting bacteria not only increased plant growth parameters under salinity stress, but also they improved soil biological indices such as soil microbial biomass carbon, basal respiration, and substrate-induced respiration and thereby indirectly enhanced plant growth conditions and increased plant yield quantity and quality.
کلیدواژهها [English]