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Under food security concerns and accelerated global warming, northern regions are becoming new agricultural frontiers. While diverse regional, national, and local policies support northern agricultural intensification and expansion through land use conversion, the scope and environmental consequences of northern agriculture are yet to be fully understood. As northern agriculture is poised to increase its role in both the local and global food production, its sustainable growth depends on a comprehensive understanding of opportunities and challenges. To evaluate the current perception of the status of northern agricultural research and the extent to which there is a need for a coordinated approach to its growth, we developed a targeted survey delivered online. Questions are aimed at revealing similarities and discrepancies in the awareness of northern agriculture and obtaining feedback on the need for a global synchronization of research and development. Out of 309 respondents, a curated dataset of 238 respondents was employed for analysis. This included respondents with knowledge and expertise in boreal and/or Arctic agriculture (41%), of temperate and/or alpine agriculture (37%), and other respondents (22%). Most are involved in agricultural (60%) or applied environmental (23.5%) sciences. Results revealed that scientists working in the northern regions are cautiously optimistic about climate change–driven expansion of northern agriculture while also realistic about the need for environmentally sustainable agricultural systems. Respondents with limited exposure to northern agriculture were more pessimistic about its expansion. Surprisingly, there was a limited and inconsistent knowledge of extant networks and research entities focusing on northern agriculture research. Nevertheless, there was a strong consensus that a concerted approach among multiple disciplines and across global regions would benefit northern agriculture and its ongoing growth. The survey's results illuminate for the very first time the need for better coordination and a greater emphasis on northern agriculture under climate change. [ABSTRACT FROM AUTHOR]

The spatial variability in soil physical and hydraulic properties for a managed podzol was assessed using soil apparent electrical conductivity (ECa). Two EMI sensors, the multi-coil (MC) and multi-frequency (MF), were adopted for measurement of ECa on a silage- corn experimental plot in western Newfoundland, Canada. Results demonstrated a significant relationship between the ECa mean relative differences (MRD) and the soil moisture content MRD (R2 = 0.33 to 0.70) for both MC and MF sensors. The difference in depth sensitivity between MC and MF sensors accounted for the variation (0.015 to 0.09) in ECa standard deviation of the relative differences. A significant linear relationship was found between the ECa MRD and sand (R2 = 0.35 and 0.53) or silt (R2 = 0.43), but not with clay (R2 = 0.06 and 0.16). The spatial variability of the ECa-based predictions (CV = 3.26 to 27.61) of soil properties was lower than the measured values (CV = 5.56 to 41.77). These results inferred that the temporal stability of ECa might be a suitable proxy to understand the spatial variability of soil physical and hydraulic properties in agricultural podzols. [ABSTRACT FROM AUTHOR]

Plant clusters govern soil microbiology in desert systems. Female Acanthosicyos horridus plants in the Namib Desert are preferentially accessed by grazers, especially during fruit availability. We hypothesized that this differential grazing affects the taxonomic diversity of soil bacterial populations. Sampling was carried out at three locations on a northwest-to-southeast transect starting at the Kuiseb Delta, near the shores of the Atlantic in the western Namib Desert, and extending inland over a distance of 140 km. Analyses of the soil samples showed that proximity to the sea had a strong impact on soil salinity. Soil pH and organic matter content were generally not significantly correlated with the presence or absence of plants and varied little and non-uniformly along the transect. A. horridus presence led to distinct under-canopy bacterial-community diversity in contrast with the non-vegetated spaces between shrubs. However, plant gender has only a marginal, statistically insignificant impact on the bacterial-diversity properties, thus not supporting our hypothesis. Therefore, the taxonomic diversity of the bacterial community in Namib Desert soils vegetated with A. horridus is primarily governed by the presence or absence of plants and by proximity to the ocean. [ABSTRACT FROM AUTHOR]

Nontuberculous mycobacteria (NTM) are widely distributed in the environment. On one hand, they are opportunistic pathogens for humans and animals, and on the other hand, they are effective in biodegradation of some persistent pollutants. Following the recently recorded large abundance of NTM in extreme geothermal environments, the aim of the study was to ascertain the occurrence of NTM in the extreme environment of the water zone of the Hranice Abyss (HA). The HA mineral water is acidic, with large concentrations of free CO2, and bacterial slimes creating characteristic mucilaginous formations. Both culture and molecular methods were used to compare the mycobacterial diversity across the linked but distinct ecosystems of HA and the adjacent Zbrašov Aragonite Caves (ZAC) with consideration of their pathogenic relevance. Six slowly growing NTM species (M. arupense, M. avium, M. florentinum, M. gordonae, M. intracellulare) and two rapidly growing NTM species (M. mucogenicum, M. sediminis) were identified in the water and in the dry zones at both sites. Proteobacteria were dominant in all the samples from both the HA and the ZAC. The bacterial microbiomes of the HA mineral water and HA slime were similar, but both differed from the microbiome in the ZAC mineral water. Actinobacteria, a phylum containing mycobacteria, was identified in all the samples at low proportional abundance. The majority of the detected NTM species belong among environmental opportunistic pathogens. [ABSTRACT FROM AUTHOR]

Microbial function, composition, and distribution play a fundamental role in ecosystem ecology. The interaction between desert plants and their associated microbes is expected to greatly affect their response to changes in this harsh environment. Using comparative analyses, we studied the impact of three desert shrubs, Atriplex halimus (A), Artemisia herba-alba (AHA), and Hammada scoparia (HS), on soil- and leaf-associated microbial communities. DNA extracted from the leaf surface and soil samples collected beneath the shrubs were used to study associated microbial diversity using a sequencing survey of variable regions of bacterial 16S rRNA and fungal ribosomal internal transcribed spacer (ITS1). We found that the composition of bacterial and fungal orders is plant-type-specific, indicating that each plant type provides a suitable and unique microenvironment. The different adaptive ecophysiological properties of the three plant species and the differential effect on their associated microbial composition point to the role of adaptation in the shaping of microbial diversity. Overall, our findings suggest a link between plant ecophysiological adaptation as a 'temporary host' and the biotic-community parameters in extreme xeric environments. [ABSTRACT FROM AUTHOR]

Quantitative viral risk assessments for wastewaters are notoriously difficult. The often considered quantitative reverse transcriptase PCR reflects poorly on virus infectivity rates leading to inaccurate risk interpretations. Various techniques focused on the degradation of the nucleic acids of non-infective viruses were previously employed. We comparatively assessed the effectiveness of such enzymatic treatments for MS2 bacteriophage in treated wastewaters. The single use of RNase A at an appropriate concentration may be as effective as the combination of RNase followed by Proteinase K and more rapid. While all tested enzymatic treatments minimized recovery of RNA (>95 %) in the absence of infective MS2, none completely eliminated the signal recovery. Selection of any enzymatic protocol for minimizing recovery of RNA from degraded, non-infective viruses should balance the methods efficacy with its expediency. [ABSTRACT FROM AUTHOR]

Water and nutrient availability are the major limiting factors of biological activity in arid and semiarid ecosystems. Therefore, perennial plants have developed different ecophysiological adaptations to cope with harsh conditions. The chemical profile of the root exudates varies among plant species and this can induce variability in associated microbial populations. We examined the influence of two shrubs species, Artemisia sieberi and Noaea mucronata, on soil microbial diversity. Soil samples were collected monthly, from December 2006 to November 2007, near canopies of both shrubs (0-10-cm depth). Samples were used for abiotic tests and determination of soil bacterial diversity. No significant differences were found in the abiotic variables (soil moisture, total organic matter, and total soluble nitrogen (TSN)) between soil samples collected from under the two shrubs during the study period. No obvious differences in the Shannon-Weaver index, evenness values, or total phylogenetic distances were found for the soil microbial communities. However, detailed denaturing gradient gel electrophoresis (DGGE) clustering as well as taxonomic diversity analyses indicated clear shifts in the soil microbial community composition. These shifts were governed by seasonal variability in water availability and, significantly, by plant species type. [ABSTRACT FROM AUTHOR]

Composted sewage sludge (biosolids) supply plant available Fe and may represent a sustainable alternative to more costly chelated Fe fertilizers currently used to supplement nutrition in hybrid poplar test plots of elevated soil pH. To test the response of poplars, field plots were amended with composted biosolids at two agricultural rates: 22.75 and 44.5 Mg ha. Iron EDDHA served as a fertilizer check and control plots received no amendment. The hybrid poplar OP-367 ( Populus deltoides × P. nigra) was planted on a 3.6 m grid spacing. Significant amounts of P and Fe originating from the sewage treatment process were detected in soils 13 months after amending. Chlorosis evaluated with a SPAD-502 meter, showed that poplars amended with biosolids remained the least chlorotic and had greater tree growth when compared to Fe EDDHA and control plots during two growing seasons. Biosolids show promise as a cost effective alternative for the remediation of Fe chlorosis in hybrid poplar agroforestry plantations and present new opportunities in northwestern New Mexico for municipalities seeking solid waste land disposal options. [ABSTRACT FROM AUTHOR]

The impact of biosolid and soil type on the movement of faecal coliforms through the vadose zone was investigated following the application of animal manure to soil. Two types of biosolid, solid and liquid manure, were applied to two soil types at a wide range of initial water contents. Bacteria present in the soil solution were collected using calibrated ceramic-porous-cup samplers. Estimated bacterial migration velocities in the soil profile were consistent with the hypothesis that bacteria move mostly through soil macropores, as the rate of transport was faster than the average pore-water velocity. Macropore transport was more likely to occur in wet soils, but it was not necessarily restricted to soils with high initial soil water content. A larger soil clay content, lower total soil porosity, and lower saturated hydraulic conductivity resulted in a greater likelihood that suspended bacteria would be funnelled through pores of larger diameter and faster pore water velocity, increasing the potential vertical transport length of bacteria through the vadose zone. Total porosity was not a significant factor in enhancing deep transport of faecal bacteria. The potential of faecal bacteria to be transported to depth in soil was correlated with the water content of the manure. We conclude that application of animal manure to soil can readily lead to groundwater contamination with faecal bacteria especially under moist soil conditions, and that macropores are important in the transport. [ABSTRACT FROM AUTHOR]