A Vertical stratification of arthropods in the dry ecosystems of Colombian Guyana: morphological patterns and their ecological implications

Introduction: Despite growing interest by the ecosystems derived from the Guyanese formations, the vertical structure of the communities and relationships of the biota with the climatic conditions in these ecosystems are unknown. Objective: Characterize the structure and vertical composition of the arthropod fauna associated with three of the most representative ecosystems of the Northern area of the serranía de La Lindosa in Colombia based on morphological and ecological parameters. Methods: The arthropod fauna was sampled, from the subsurface soil level to the shrub and tree stratum. The fauna was determined up to the level of family or supraspecific group and the values of Alfa and Beta diversity were determined. Body length measurements were made, and the coloration and trophic level of each group were determined. Results: The composition and diversity of the arthropod fauna was different in each ecosystem and vertical stratum and most of the groups in all the ecosystems studied present low abundances. Groups of phytophagous and predatory habits were frequent in all ecosystems and the highest biomass of arthropod fauna comes from groups of polyphagous habits, of medium size and great abundance. Light and dark colorations are the most frequent in landscape-scale. Conclusion: The ecosystems studied are characterized by the low values of diversity and replacement and the large number of non-shared groups that apparently respond to the microclimatic characteristics; however, there are some generalities on a landscape scale such as the greater richness and abundance of groups in the intermediate strata, the greater proportion of groups with phytophagous habits and medium body sizes, and the predominance of dark colorations in the lower strata.

Study on combined machine for the subsurface soil treatment

The purpose of the study is to substantiate the relative position of the working bodies of a combined machine for non-fall tillage of winter crops. The design scheme and the principle of operation of the combined machine are given. The basic principles and methods of classical mechanics, mathematical analysis and statistics were used in this study. It is established that the most optimal design scheme of a combined machine for non-tillage of the soil and its preparation for sowing of repeated crops is considered to be a scheme consisting of non-tillage cases with crushers, a battery with cut-out spherical disks and a roller. According to the results of theoretical and experimental studies, it was found that with a longitudinal distance between the shaft-free bodies of 40 cm and a transverse distance of 90 cm, a longitudinal distance from the toe of the ploughshare to the center of the support wheel of 50 cm and a longitudinal distance from the toe of the ploughshare of the shaft-free body to the axis of rotation of the cut-out spherical disk of 120 cm, a longitudinal distance from the axis of rotation of the cut-out spherical disk to the center of the roller of 75 cm, high-quality tillage with minimal energy costs is provided.

High-Resolution Direct Push Sensing in Wetland Geoarchaeology—First Traces of Off-Site Construction Activities at the Fossa Carolina

Wetland environments, with their excellent conservation conditions, provide geoarchaeological archives of past human activities. However, the subsurface soil is difficult to access due to high groundwater tables, unstable sediments, and the high cost of excavation. In this study, we present a ground-based non- and minimal-invasive prospection concept adapted to the conditions of wetlands. We investigated the Fossa Carolina in South Germany, a canal that was intended in 792/793 AD by Charlemagne to bridge the Central European Watershed. Although the resulting Carolingian banks and the fairway with wooden revetments are very imposing, archaeological traces of off-site construction activities have not been identified hitherto. Based on a geophysically surveyed intensive linear magnetic anomaly parallel to the Carolingian canal, we aimed to prove potential off-site traces of Carolingian construction activities. In this context, we built up a high-resolution cross-section using highly depth-accurate direct push sensing and ground-truthing. Our results showed the exact geometry of the canal and the former banks. Thus, the magnetic mass anomaly could be clearly located between the buried organic-rich topsoil and the Carolingian banks. The thermoluminescence dating showed that the position of the magnetic mass anomaly reflected Carolingian activities during the construction phases, specifically due to heat exposure. Moreover, we found hints of the groundwater supply to the 5-metre wide navigable fairway.

Plant production-community composition relationship associated with fungal guilds depends on grassland disturbance in surface and subsurface soils

Purpose Soil fungal guilds have been proven to influence the plant community composition-production relationship, but not much is known about their effects on surface and subsurface soils under different disturbances. Methods Here, we assessed the functional characteristics of three fungal groups using the Ribosomal Database Project (RDP) classifier and data available in FUNGuild, and we characterized the community of saprotrophic, mycorrhizal, and potential plant pathogenic fungi in surface (0–10 cm) and subsurface soils (10–20 cm) of temperate grasslands under different management practices. Results We found that grassland disturbances decreased plant aboveground production and changed plant community composition. In surface soil, antagonistic interaction between potential plant pathogens and saprotrophic fungi drove the plant community composition-production relationship. In subsurface soil, this relationship was driven by antagonistic interaction between mycorrhizal fungi and potential plant pathogens. Conclusion These findings revealed that under grassland disturbances, the surface soil fungal communities were more strongly associated with plant community composition-production relationship than those from the subsurface soil were. Potential plant pathogens played an important role in plant community composition-production relationship. This knowledge is important for predicting the shifts in ecosystem functions as a consequence of changes in soil fungal groups during grassland management.

Geophysical Assessment of Impact of E-Waste Pollutants on the Subsurface Soil of Alaba International Market Dumpsite in Lagos, Nigeria.

Soil degradation forms a part of the significant impacts arising from indiscriminate disposal of e-waste. This study was aimed at assessing the magnitude of legacy contamination by e-waste, particularly, its depth and spread in the subsurface soil of Alaba International Market e-waste dumpsite in Lagos, Nigeria through the analysis of VES and 2D-Wenner array configuration data acquired on the dumpsite. The results of the VES data and 2D resistivity analysis showed that Alaba dumpsite was highly impacted by e-wastes due to the permeable geo-electric characteristics of the lithologic units beneath the dumpsite. The lithogy enables the pollutants to spread laterally and progressively increase in depth through sand column subsurface to more than 30m. It also showed that the contaminated zones are characterised by resistivity values ranging from 5.0 to 8.3 Ω.m. The study site is highly populated with wells and boreholes as the main sources of water for the community, thus the findings from this study could facilitate Lagos State Government decisions on improving protection for groundwater resources around the study area.

Effects of scattered Faidherbia albida and Cordia africana Tree on Soil Properties under their Canopies in Fedis District, Easte Hararghe Zone, Oromia

The study was conducted to investigate the effect of scattered trees under their canopies on soil fertility status at Fedis district, East Hararghe Zone, oromia, Ethiopia. Accordingly, six isolated and nearly identical Faidherbia albida and Cordia africana trees were selected and the canopy coverage of each tree was divided into four radial transects. Soil samples from three horizontal distances levels: 2.5m, 5m and 25m with two soil depths levels (0–20cm and 20-40cm) were taken for analysis of soil physical and chemical properties and tree species with two levels with factorial arrangement in RCBD replicated six times were employed. The result revealed soil texture was not influenced significantly (P>0.05) by tree species. Soil bulk density was significantly (p<0.05) influenced by both tree species. Soil moisture was significantly (p<0.05) higher under canopy of trees than open field and in surface than in subsurface soils. Soil chemical properties;- electric conductivity, organic carbon, organic matter, soil carbon stock, total nitrogen, available phosphorus and exchangeable cation (Mg, Ca, Na and K) for surface and subsurface soil layers of under F.albida and C. africana trees were significantly (p<0.05) higher in canopy than open field and in surface than subsurface. Soil pH was not significantly (p>0.05) influenced by both tree species. It can be concluded that these tree species have the potential to improve soil fertility beneath its canopy. This may be important for the agricultural landscape health and demonstrated the scattered trees to retain on crop fields to improve soil fertility status under its canopy and on farm biodiversity conservation in agricultural landscapes conditions.

Bacterial Movement in Subsurface Soil during Winter Irrigation of Reclaimed Wastewater

Processes to remove and inactivate Escherichia coli from wastewater effluents and drainage are complex and interrelated. The objective of this study was to determine if irrigation of undisinfected wastewater effluents in the winter moves bacteria to surface water through subsurface drainage, posing a public health risk. The central Ohio study site, an open meadow constructed in the 1970s, is irrigated with lagoon effluents each summer. The irrigated area has subsurface drainage that collects for discharge in one spot. Undisinfected wastewater from a stabilization pond was irrigated for the first time in the winter of 2013/2014. E. coli was measured in the subsurface discharge during the irrigated winter season and compared to the non-irrigated previous winter season. Soil temperature and moisture were also monitored. E. coli moved to subsurface drains when the water table was above the drain. E. coli also moved to subsurface drains when the shallow soil temperature dropped to near freezing. With less winter sunlight and minimal evapotranspiration, the soil stayed moist near field capacity. Temperature appears to be the most important factor in limiting natural inactivation in subsurface soil and allowing the movement of E. coli in undisinfected wastewater effluents to the subsurface drainage systems. The results show that winter reuse of undisinfected wastewater does pose a public health risk to surface water through subsurface drainage. Therefore, disinfection of wastewater effluents used for irrigation is strongly recommended.

Implications of the Engineering Geological Properties of Soils in the Implementation of the Greater Jos Master Plan, North Central Nigeria

A study of the engineering properties of the subsurface soil in the Greater Jos Master Plan development area has been carried out to address the paucity of engineering data in the area. The study became necessary because the rapid urbanization has led to limited construction land with more ground prone to instability due to reworking by mining and related activities. The study area is located within Latitudes 09º 48' 20'' to 09º 53'20''N and Longitudes 08º 53' 54'' to 08º 57 '00'' E and extending over 54km2 on Naraguta Sheet 168NE. Surface geological mapping was carried out to confirm the existing geology. Geotechnical properties of soils were determined by analysis of soil samples for 38 locations. While 94 static water level measurements provided additional information on groundwater conditions. The area is underlain by the Jos-Bukuru Complex rocks predominantly biotite granites differentiated on the basis of mode of formation, mineralogy and texture. Soils derived from weathering of the rocks revealed gradual decomposition from gravel, sand, and silt-sized particles to lateritic clays. The soils are considered to have low to medium plasticity/compressibility, expansiveness, and swelling potential across all rock types. The static water table depicts fluctuation in the water table varying between 2.9 and 3.9m. These findings are expected to serve as guide in the choice of design and construction and as a baseline subsurface soil compendium for planning and urban development in the Greater Jos Master plan and for further studies.