Soil Matrix Determines the Outcome of Interaction Between Mycorrhizal Symbiosis and Biochar for Andropogon gerardii Growth and Nutrition

Biochar has been heralded as a multipurpose soil amendment to sustainably increase soil fertility and crop yields, affect soil hydraulic properties, reduce nutrient losses, and sequester carbon. Some of the most spectacular results of biochar (and organic nutrient) inputs are the terra preta soils in the Amazon, dark anthropogenic soils with extremely high fertility sustained over centuries. Such soil improvements have been particularly difficult to achieve on a short run, leading to speculations that biochar may need to age (weather) in soil to show its best. Further, interaction of biochar with arbuscular mycorrhizal fungi (AMF), important root symbionts of a great majority of terrestrial plants including most agricultural crops, remains little explored. To study the effect of aged biochar on highly mycotrophic Andropogon gerardii plants and their associated AMF, we made use of softwood biochar, collected from a historic charcoal burning site. This biochar (either untreated or chemically activated, the latter serving as a proxy for freshly prepared biochar) was added into two agricultural soils (acid or alkaline), and compared to soils without biochar. These treatments were further crossed with inoculation with a synthetic AMF community to address possible interactions between biochar and the AMF. Biochar application was generally detrimental for growth and mineral nutrition of our experimental plants, but had no effect on the extent of their root colonized by the AMF, nor did it affect composition of their root-borne AMF communities. In contrast, biochar affected development of two out of five AMF (Claroideoglomus and Funneliformis) in the soil. Establishment of symbiosis with AMF largely mitigated biochar-induced suppression of plant growth and mineral nutrition, mainly by improving plant acquisition of phosphorus. Both mycorrhizal and non-mycorrhizal plants grew well in the acid soil without biochar application, whereas non-mycorrhizal plants remained stunted in the alkaline soils under all situations (with or without biochar). These different and strong effects indicate that response of plants to biochar application are largely dependent on soil matrix and also on microbes such as AMF, and call for further research to enable qualified predictions of the effects of different biochar applications on field-grown crops and soil processes

Natural formation and degradation of chloroacetic acids and volatile organochlorines in forest soil: challenges to understanding

Goal, Scope and Background. The anthropogenic environmental emissions of chloroacetic acids and volatile organochlorines have been under scrutiny in recent years because the two compound groups are suspected to contribute to forest dieback and stratospheric ozone destruction, respectively. The two organochlorine groups are linked because the atmospheric photochemical oxidation of some volatile organochlorine compounds is one source of phytotoxic chloroacetic acids in the environment. Moreover, both groups are produced in higher amounts by natural chlorination of organic matter, e.g. by soil microorganisms, marine macroalgae and salt lake bacteria, and show similar metabolism pathways. Elucidating the origin and fate of these organohalogens is necessary to implement actions to counteract environmental problems caused by these compounds. Main Features. While the anthropogenic sources of chloroacetic acids and volatile organochlorines are relatively well-known and within human control, knowledge of relevant natural processes is scarce and fragmented. This article reviews current knowledge on natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soils, with particular emphasis on processes in the rhizosphere, and discusses future studies necessary to understand the role of forest soils in the formation and degradation of these compounds. Results and Discussion. Reviewing the present knowledge of the natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soil has revealed gaps in knowledge regarding the actual mechanisms behind these processes. In particular, there remains insufficient quantification of reliable budgets and rates of formation and degradation of chloroacetic acids and volatile organochlorines in forest soil (both biotic and abiotic processes) to evaluate the strength of forest ecosystems regarding the emission and uptake of chloroacetic acids and volatile organochlorines, both on a regional scale and on a global scale. Conclusion. It is concluded that the overall role of forest soil as a source and/or sink for chloroacetic acids and volatile organochlorines is still unclear; the available laboratory and field data reveal only bits of the puzzle. Detailed knowledge of the natural degradation and formation processes in forest soil is important to evaluate the strength of forest ecosystems for the emission and uptake of chloroacetic acids and volatile organochlorines, both on a regional scale and on a global scale. Recommendation and Perspective. As the natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soil can be influenced by human activities, evaluation of the extent of this influence will help to identify what future actions are needed to reduce human influences and thus prevent further damage to the environment and to human health caused by these compounds

The evaluation of the microbial diversity in anthropogenic subtrates using a method analyzing the polymorphism of the terminal restriction fragments of DNA

In this methodology we describe a fast, easy and non-expensive method for evaluation of microbial diversity in various types of substrates: T-RFLP. We explain principles and describe in detail the workflow of DNA extraction, amplification of a particular piece of DNA in PCR, choice of restriction enzymes and the restriction digest, separation of fragments using the capillary sequencer as well as discuss the evaluation and interpretation of the results

Study of interaction between plant, arbuscular mycorrhize fungiand saprophytic microorganisms in soil

Cultivation of microorganisms is necessary for experimentswith them

Methods of study of interactions in rhizosphere

In past few years a role of arbuscular mycorrhizis in plant-soil systém come in light again

Response of micropropagated potatoes transplanted to peat media to post-vitro inoculation with arbuscular mycorrhizal fungi and soil bacteria

Abstract Positive effects of dual inoculation with some combinations of arbuscular mycorrhizal fungi (AMF) and bacteria on the growth of micropropagated potato (Solanum tuberosum) transplanted to a peat-based substrate were found in three different cultivation systems -pots, greenhouse or shadowhouse beds. Some inoculation treatments, e.g. with Glomus etunicatum, Glomus fistulosum together with bacterial isolate B1 (Bacillus subtilis) in pots, or with Glomus fistulosum plus bacteria B1 in greenhouse beds or with a mixture of Glomus manihotis and two bacteria in shadowhouse beds resulted in higher number of minitubers (NT), higher weight per minituber or in higher total weight of minitubers per plant. However, the effects of mycorrhization varied for two different potato varieties and the synergistic effects of coinoculation with different bacteria isolated from rhizosphere or hyphosphere was not significant in most cases. There were no significant effects of Zeolite (clinoptinolite clay) amendment on the mycorrhization and aboveground growth of potato plants, while slight stimulation was observed for minituber weight. The inoculation into peat-based substrate might be successful regarding plant growth response; however, to increase the potential of the inoculation in practical production of potato minitubers, it is necessary to consider possible differences of various potato varieties and to select appropriate combination of bacteria and AMF symbionts

Arbuscular Mycorrhizal Fungus <i>Funneliformis mosseae</i> Improves Soybean Growth Even in Soils with Good Nutrition

Arbuscular mycorrhizal fungi (AMF) improve plant growth and may be useful in maintaining and even restoring soil. However, data on the latter function are sparse and only indirect, which is especially true for conventional management conditions with adequate nutrient availability. Our study focused on utilizing the prevalent AMF species, Funneliformis mosseae, to enhance Glycine max production, while also exploring its partly explored impact on soil aggregation. Working in greenhouse conditions, we examined whether, in a nutrient-sufficient environment, AMF would improve crop biomass accumulation and nutrition, as well as the stability of soil aggregates (SAS). We also looked for a synergistic effect of dual inoculation using AMF and symbiotic rhizobium. Plants were or were not inoculated with AMF or Bradyrhizobium japonicum in a two-factorial design. AMF inoculation increased soybean biomass, but AMF inoculation had no impact on P and N input to the shoots. Mycorrhiza did not affect either glomalin abundance or SAS. All the impacts were, however, independent from rhizobial inoculation, which was ineffective in this nutrient-available environment. Our assay suggests that arbuscular mycorrhiza may have a positive effect on soybean growth even under conventional management with adequate nutrition. The positive effects of AMF on soybean growth, together with the fact that AMF generally do not thrive in good nutrient availability, should be taken into account when planning mineral fertilization levels

Tracing of the inoculated arbuscular mycorrhizal fungal strain Glomus intraradices BEG140 in a field experiment over 3 years

International audienc