RESUMO
In March 2016, the EU Commission presented a proposal for new regulations on fertilising material. The regulation includes product rules for a wide range of organic and inorganic products. Microbial biostimulants is one of the categories of products that are included. Biostimulants, in the draft EU regulation, are defined as fertilising materials that affect nutrient processes independently of the product's own nutrient content and with the purpose of improving nutrient utilisation, tolerance for abiotic stress or quality of the crop. Positive list in which species of these bacterial genera are listed: Azotobacter spp, Rhizobium spp., Azospirillum spp and Mycorrhizal fungi are a part of the regulation. Since the import and use of these organisms are the responsibility of both the Norwegian Food Safety Authority and the Norwegian Environment Agency, they asked VKM to submit a joint report on effects on health (humans, plants and animals), biodiversity and dispersal, quality of agricultural land and on soil environment. Conclusions: Health risks: Based upon our literature review, we have found no indication of any specific diseases in plants, animals or humans induced by the discussed microorganisms. A few reported cases of human disease are caused through wound infections or injections in immunocompromised patients. These represent a situation where any microorganism may induce infections and is not specific for the agents discussed in this report. In summary, the risk of any disease caused by the discussed microorganisms is considered negligible. Environmental risks: In soil the biodiversity, competition, adaptation and functional redundancy of microorganisms are extremely high. This means that introduced microorganisms have a very small chance for establishing, and even less so for affecting biodiversity and soil functioning. Introduction of nitrogen fixing species or fungi that can transport P to plants (mycorrhiza) will lead to an increase in the primary production. However, even a large increased activity for these processes will not outcompete naturally occurring symbiotic N-fixation or growth of inherently non-mycorrhizal plant species. Thus, the risks associated with introduced non-pathogenic microorganisms are very low.
RESUMO
It is well established fact that bacterial species promotes plant growth. This growth enhancing activity was believed to be through different mechanisms such as synthesis of phytohormones, nitrogen-fixing, and biological control. For this reason, in this present investigation we have isolated and identified Azotobacter spp. and Azospirillum spp. through macromorphologically and micromorphologically in order to assess its effect on growth and yield of strawberry (Fragaria vesca) an Albion variety in hydroponic system. The inoculation and co-inoculation of bacterial culture was performed in combination with three nitrogen levels (50, 100 and 150 ppm), growth parameters such as plant height, root length, fresh and dry weight of root and aerial parts, leaf area, chlorophyll content, nutrient content, solid soluble, caliber, yield/plant. It is observed that in T8 (co-inoculation in100 ppm N) group showed significantly increase in plant height (18.57cm), chlorophyll content (48.57 Soil Plant Analysis Development-SPAD), fresh root weight (25.82g) and dry root weight (5.93g), while in treatment group T5 (Azotobacter spp. 100ppm of Nitrogen) and T6 (Azotobacter spp. 150ppm of Nitrogen) showed significant increase in root length, leaf area, dry and fresh weights of aerial parts. The N content of leaf for all treatments was in the ranges of 2.42 - 2.83 % that is suitable for cultivation. Similarly, the treatment group T5 and T6 showed increase in yield per plant and soluble solids content. So, Azotobacter and Nitrogen treatment has growth related benefits in strawberries under hydroponic system.
RESUMO
Biofertilizers are an alternative to mineral fertilizers for increasing soil productivity and plant growth in sustainable agriculture. The objective of this study wheat plant growth promoting by non symbiotic (Azotobacter spp.)Strains as biofertilizer on soil properties and seedling growth of wheat in soil, and the application treatments included the control (without bacteria inoculation), non symbiotic organism isolated saline desert soil in which studied soil all properties. Checked nitrogen fixing activity, IAA producing activity and studied activity against pesticide of all isolated and record results.
RESUMO
The objectives of this study were to count and culture Azotobacter spp. in sampled soils, to determine the nitrogen (N) fixing capacity by Azotobacter spp. in pure culture and different soils, and to explore the relationships between N fixation capacity of Azotobacter spp. and microbiological properties of soils in Northern Anatolia, Turkey. Statistically significant relationships were found between the population of Azotobacter spp. in soils and microbial biomass C (Cmic ), dehydrogenase (DHA), b-glucosidase (GA), alkaline phosphatase (APA) and arylsulphatase (ASA) activities. However, relationships between the population of Azotobacter spp. and basal soil respiration (BSR), urease (UA) and catalase (CA) activities were insignificant. The N fixation capacities of native 3 day old Azotobacter chroococcum strains added to Ashby Media varied from 3.50 to 29.35 μg N ml-1 on average 10.24. In addition, N fixation capacities of Azotobacter spp. strains inoculated with clayey soil, loam soil, and sandy clay loam soil during eight week incubation period were 4.78-15.91 μg N g-1, 9.03- 13.47 μg N g-1 and 6.51-16.60 μg N g-1, respectively. It was concluded that the most N fixation by Azotobacter spp. was in sandy clay loam soils.