Biological Soil Amendments Research Articles

Field Scale Phytoremediation Experiments on a Former U Mining Site and Further Processing of the Plant Material

The remediation of large heavy metal/radionuclide (HM/R) contaminated areas by conventional ex-situ techniques (excavation or chemical treatment/-stabilization) is expensive, and low cost strategies with a long-term stabilization effect of such sites are a task of next years research. Phytoremediation can be an alterative solution and sustainable technology since low treatment costs make it feasible even for such sites. Field scale investigation is applied to an area of the former uranium mining in East Thuringia, Germany. On this area, a low grade uranium ore leaching dump was situated, which was later removed during the remediation process of the site. Now, an underground remains that is slightly to moderately contaminated with heavy metals and radionuclides (HM/R) with restrictions of land use. Concepts for remediation of HM/R-contaminated sites and for the subsequent utilization of the HM/R-loaded plant residues are developed in a joint project. Plant experiments with Triticale, Helianthus annuus,Brassica juncea and Sorghumbicolor were performed revealing the influence of biological additives (mycorrhiza, HM-resistant streptomyces) and soil amendment strategies (increasing pH and organic matter) on biomass production and plant tolerance to heavy metals. The addition of mycorrhiza and streptomyces (MS) had a significant effect on biomass, and decreased the bioavailable parts of HM/R (e.g. Ni, Sr, U) in soil in comparison to untreated polluted soil with all studied plants. In lysimeter experiments it was figured out, that the different soil improvement strategies, addition of MS and of calcareous top soil (MIX) resulted in a reduction of the concentration of contaminants in the seepage water, as well as of the seepage water rates and loads, thus decreasing the risk of groundwater contamination. Finally, the processing of the heavy metal loaded plant residues was investigated by different methods. Fermentation experiments carried out with Solanum tuberosum and Secale cereale achieved good results compared with industrial standards. Remaining plant parts can be processed in a biogas process, or combusted. Fermentation sludges and combustion ashes act as sinks for HM/R. As results of the project, phytoremediation is a convenient method for the stabilization and remediation of large sites with slight to medium contaminations, and a further utilization of the plant residues by fermentation and biogas production is feasible.

Field scale phytoremediation experiments on a heavy metal and uranium contaminated site, and further utilization of the plant residues

The remediation of large heavy metal/radionuclide (HM/R) contaminated areas by conventional remediation technologies is often too expensive. Phytoremediation can be an alternative for such areas with slight contaminations, and represents a convenient and sustainable method of remediation. Field site phytoremediation experiments were carried out at a former uranium mining area in East Germany. The test field site is slightly to moderately contaminated with HM/R; the phytoremediation was performed by combination of phytostabilization and phytoextraction methods combining microbial, soil and plant techniques both at field- and lab scale. Plant experiments with Triticale, Helianthus annuus and Brassica juncea were performed to investigate the influence of biological additives (fungi, bacteria) and soil amendment strategies (increasing pH and organic matter, fertilizing) on biomass production and plant tolerance to heavy metals. In lysimeter experiments, a minimization of HM/R accumulation in soil could be shown, and groundwater contamination as well as seepage water rate and load could be reduced. The final utilization of HM/R loaded plant residues after harvests was studied by biogas and ethanolic fermentations and by combustion of the plant material. The fate of HM/R in the different by-products was investigated. Finally, concepts were developed for the utilization of the HM/R loaded plant residues.

Soil solarization: a non-chemical approach for management of plant pathogens and pests

Soil solarization is a special mulching process which causes hydrothermal disinfestation and other physical and biological changes in soil which are beneficial to plant health and growth. Plastic film laid over moist soil during periods of high air temperature, usually for 1–2 months, can greatly reduce or eradicate a number of pathogens and pests including fungi, bacteria, nematodes, arthropods and weeds. Following soil solarization, growth of microflora beneficial to plant growth or antagonistic to pathogens and pests may slow the reinfestation of soil by these organisms for more than one growing season. Increased plant growth and yield of annual and perennial field, row, and nursery crops usually occur following soil solarization. In addition, the availability of increased mineral nutrients following solarization may reduce crop fertilization requirements. Soil solarization has been effective as a pre-plant and as a post-plant treatment, and has been compatible with chemical soil treatments and also biological soil amendments after solarization. Soil solarization is a significant advance in the non-chemical control of many pathogens and pests.

Kumri—so-called Lumbar Paralysis—Of Horses in Ceylon (India And Burma), and its Identification with Cerebrospinal Nematodiasis

For over a decade, Salmonella contamination has increasingly led to outbreaks of foodborne illness associated with fresh produce. The use of untreated animal manures, or biological soil amendments of animal origin, to amend agricultural soils holds a risk of contamination from foodborne pathogens, such as Salmonella. This study was conducted to determine the prevalence, concentration, serotypes, and antimicrobial resistance profiles of Salmonella in poultry litter from Florida farms. Litter pH, total Kjeldahl nitrogen, total ammonia nitrogen, total phosphorus (P2O5), total potassium (K2O), moisture content, total solids, total ash, organic matter, and aerobic plate count (APC) were also measured. Litter samples (n = 54) were collected from 18 broiler farms across three seasons (spring, summer, and winter). Salmonella concentrations were enumerated using a most-probable-number (MPN) method, and antimicrobial susceptibility testing was performed. The prevalence of Salmonella in litter samples was 61.1%, with a geometric mean of 0.21 ± 20.7 MPN/g. Across all seasons, Salmonella concentrations were not influenced by the chemical, physical, or microbial properties measured. Recovered Salmonella isolates (n = 290) were grouped into serogroups O:4 (43.1%), O:7 (26.9%), O:8 (11.0%), O:1,3,10,19 (7.9%), and O:9,46 (7.2%). Serotyping Salmonella isolates (n = 47) resulted in 12 serotypes, with the most common being Typhimurium (27.7%), Kentucky (17.0%), Enteritidis (14.9%), and Mbandaka (14.9%). Antimicrobial resistance to tetracycline (29.8%), sulfisoxazole (23.4%), and streptomycin (14.9%) was observed. No isolates were resistant to more than two antimicrobial agents. This study provides valuable information for future risk assessments for the use of poultry litter as an untreated biological soil amendment of animal origin.Prevalence and concentration of Salmonella in Florida poultry litter were examined.Serovars Typhimurium, Kentucky, Enteritidis, and Mbandaka were most common.Antimicrobial resistance to tetracycline, sulfisoxazole, and streptomycin was seen.Multidrug-resistant Salmonella isolates were not observed.