Effects on Glomus mosseae

Greenhouse experiments were conducted to assess the effects of inoculating winter wheat (Triticum aestivum) with plant growth promoting rhizobacteria (PGPR) of the genus Paenibacillus under phosphate P-limited soil conditions in the presence or absence of the arbuscular mycorrhizal fungus (AMF) Glomus mosseae. Four P. polymyxa strains and one P. brasilensis strain were compared at two cell concentrations (106 and 108 cells g−1 seeds) of inoculation, and surface sterilized AMF spores were added to pots. Mycorrhizal root colonization, plant growth, and plant uptake of phosphorus were analyzed. Bacterial phosphate solubilization was examined separately in vitro. Most P. polymyxa strains, isolated from wheat, had dramatic effects per se on root growth and root P-content. No treatment gave significant effect on shoot growth. AMF root colonization levels and total plant uptake of P were much stimulated by the addition of most P. polymyxa strains. The AM fungus alone and the P. brasilensis, alone or in combination with the fungus, did not affect total plant P-levels. Our results indicate that practical application of inoculation with plant host-specific rhizobacteria (i.e., P. polymyxa) could positively influence uptake of phosphorus in P-deficient soils by wheat plants, provided that suitable AM fungi (e.g., G. mosseae) are present

Specific interactions between arbuscular mycorrhizal fungi and plant growth-promoting bacteria--as revealed by different combinations

The interactions between two plant growth promoting rhizobacteria (PGPR), Pseudomonas fluorescens SBW25 and Paenibacillus brasilensis PB177, two arbuscular mycorrhizal (AM) fungi (Glomus mosseae and G. intraradices) and one pathogenic fungus (Microdochium nivale) were investigated on winter wheat (Triticum aestivum cultivar Tarso) in a greenhouse trial. PB177, but not SBW25, had strong inhibitory effects on M. nivale in dual culture plate assays. The results from the greenhouse experiment show very specific interactions; e.g. the two AM fungi react differently when interacting with the same bacteria on plants. G. intraradices (single inoculation or together with SBW25) increased plant dry weight on M. nivale infested plants, suggesting that the pathogenic fungus is counteracted by G. intraradices, but PB177 inhibited this positive effect. This is an example of two completely different reactions between the same AM fungus and two species of bacteria, previously known to enhance plant growth and inhibit pathogens. When searching for plant growth promoting microorganisms it is therefore important to test for the most suitable combination of plant, bacteria and fungi in order to get satisfactory plant growth benefits

Closing the Global Energy and Nutrient Cycles through Application of Biogas Residue to Agricultural Land – Potential Benefits and Drawback

Anaerobic digestion is an optimal way to treat organic waste matter, resulting in biogas and residue. Utilization of the residue as a crop fertilizer should enhance crop yield and soil fertility, promoting closure of the global energy and nutrient cycles. Consequently, the requirement for production of inorganic fertilizers will decrease, in turn saving significant amounts of energy, reducing greenhouse gas emissions to the atmosphere, and indirectly leading to global economic benefits. However, application of this residue to agricultural land requires careful monitoring to detect amendments in soil quality at the early stages

Utilization of Natural Farm Resources for Promoting High Energy Efficiency in Low-Input Organic Farming

Both organic and conventional farming processes require energy input in the form of diesel fuel for farming equipment, animal feed, and fertilizer compounds. The most significant difference between the two methods is the use in conventional farming of mineral fertilizers and pesticides that are minimally employed in organic management. It is argued that organic farming is more environmentally friendly, given that synthetic fertilizers mainly used at conventional farms are replaced with animal manure and cover crops. Nutrient uptake by plants is additionally enhanced by the effective use of rhizobia and other types of plant growth-promoting bacteria, in combination with arbuscular mycorrhizal fungi. This article aims to compare the amounts and/or types of energy and nutrients required for both farming systems and provide feasible suggestions for the sustainable use of farm resources in combination with good crop yields

Utilization of Natural Farm Resources for Promoting High Energy Efficiency in Low-Input Organic Farming

Both organic and conventional farming processes require energy input in the form of diesel fuel for farming equipment, animal feed, and fertilizer compounds. The most significant difference between the two methods is the use in conventional farming of mineral fertilizers and pesticides that are minimally employed in organic management. It is argued that organic farming is more environmentally friendly, given that synthetic fertilizers mainly used at conventional farms are replaced with animal manure and cover crops. Nutrient uptake by plants is additionally enhanced by the effective use of rhizobia and other types of plant growth-promoting bacteria, in combination with arbuscular mycorrhizal fungi. This article aims to compare the amounts and/or types of energy and nutrients required for both farming systems and provide feasible suggestions for the sustainable use of farm resources in combination with good crop yields

Persistence and spread of Salmonella enterica serovar Weltevreden in soil and on spinach plants

Several outbreaks caused by pathogenic bacteria are related to the consumption of raw produce contaminated by animal manure. The majority of these outbreaks have been linked to Salmonella spp. We examined the ability of Salmonella enterica serovar Weltevreden to persist and survive in manure and soil as well as disseminate to, and persist on, spinach roots and leaves. Significantly higher numbers of S. Weltevreden inoculated into manure and applied to soil before planting spinach were found in soil than in pot cultures, where the pathogen had been inoculated directly into soil 14 days postplanting. Moreover, the pathogen seemed to disperse from manure to spinach roots, as we observed a continuous increase in the number of contaminated replicate pot cultures throughout the evaluation period. We also found that, in some cases, S. Weltevreden present in the phyllosphere had the ability to persist for the entire evaluation period (21 days), with only slight reductions in cell numbers. The results from the present study show that S. Weltevreden is capable of persisting in soil, roots and shoots for prolonged periods, indicating the importance of strict monitoring of untreated animal manure before considering its application to agricultural land