Type and quantity of organic amendments determine the amount of carbon stabilized in particle-size fractions of a semiarid degraded soil

A 9-month lab experiment was carried out with three different amendments (vine pruning wastes, PW; composted vine pruning wastes, cPW; and sewage sludge, SS) added at three different rates (90, 180, and 240 t ha^?1, dry weight) in order to test whether the type or the quantity of the amendments applied to a semiarid, degraded soil determined the C_org accumulation in its particle-size fractions (coarse sand, 200–2,000 µm; fine sand, 63–200 µm; silt, 2–63 µm; and clay, 0.1–2 µm). All amendments, independently of their C/N ratios, resulted in similar C_org content and accumulation in coarse sand and silt-sized fractions after 9 months. In the clay-sized fraction, enrichment in C_org produced the incorporation of particles from this particle-size fraction into the silt-sized fraction. Likewise, increasing the application rates of the amendments led to larger C_org contents into the particle-size fractions of all amended soils except for the clay-sized fraction. The application of SS resulted in lower basal respiration-to-C_org ratios in the clay-sized fraction than the application of PW and cPW, suggesting a higher protection of the C_org in the SS treatment. These results indicate that organic amendments from woody plants with C/N ratios higher than 30, such as PW, favor C_org accumulation in the fine sand-sized fractions. Furthermore, our findings suggest that the application rate of such amendments, rather than the C/N ratios and amendment origin (from sludge or woody plants), is the key factor for promoting C_org accumulation in the silt-sized fractions of semiarid degraded soils.     

Relationship between inbreeding and milk production traits in two Italian dairy sheep breeds

The effects of inbreeding in livestock species breeds have been well documented and they have a negative impact on profitability. The objective of this study was to evaluate the levels of inbreeding in Sarda (SAR, n = 785) and Valle del Belice (VdB, n = 473) dairy sheep breeds and their impact on milk production traits. Two inbreeding coefficients (F) were estimated: using pedigree (F_PED), or runs of homozygosity (ROH; F_ROH) at different minimum ROH lengths and different ROH classes. After the quality control, 38,779 single nucleotide polymorphisms remained for further analyses. A mixed-linear model was used to evaluate the impact of inbreeding coefficients on production traits within each breed. VdB showed higher inbreeding coefficients compared to SAR, with both breeds showing lower estimates as the minimum ROH length increased. Significant inbreeding depression was found only for milk yield, with a loss of around 7 g/day (for SAR) and 9 g/day (VdB) for a 1% increase of F_ROH. The present study confirms how the use of genomic information can be used to manage intra-breed diversity and to calculate the effects of inbreeding on phenotypic traits.     

Changes in Hydrocarbon Composition and Autochthonous Microorganism Growth of Contaminated Mining Soil During Bioremediation

The goal of this study was to evaluate the effect of high Tween 80 concentrations on hydrocarbon contaminants and hydrocarbonoclastic microorganisms present in contaminated mining soil during a bioremediation process. The independent variables included Tween 80 concentration and process time. The elected response variables included concentration of total petroleum hydrocarbons (TPH), the chemical composition of contaminants, viable microbial count, and CO₂ production. These were measured at various time points during the bioremediation process, which was conducted at room temperature. Higher removal of pollutants occurred at low Tween 80 concentrations. An analysis of the normalized variables shows that the rate of TPH degradation depended on microbial growth rate, which depended on Tween 80 concentration. The addition of Tween 80 changed the concentration and type of the residual hydrocarbon contaminants present, as well as the count and genus of the hydrocarbonoclastic microorganisms that grew during the bioremediation process. Higher concentrations of Tween 80 increased the levels of the chemical compounds present in the bioremediated soil while reducing the viable count and microbial diversity during the bioremediation process. Conversely, low Tween 80 concentrations produced only monoethylhexyl phthalate, which is not a petroleum hydrocarbon derivative. Overall, these results prove that the removal of TPH is dependent on the count and genus of active indigenous hydrocarbonoclastic microorganisms in soil, and these conditions may be controlled by modulating the concentration of Tween 80 that is applied.     

Monitoring and Modeling Nitrate Persistence in a Shallow Aquifer

A modeling study on fertilizer by-products fate and transport was performed in an unconfined shallow aquifer equipped with a grid of 13 piezometers. The field site was located in a former agricultural field overlying a river paleochannel near Ferrara (Northern Italy), cultivated with cereals rotation until 2004 and then converted to park. Piezometers were installed in June 2007 and were monitored until June 2009 via pressure transducer data loggers to evaluate the temporal and spatial variation of groundwater heads, while an onsite meteorological station provided data for recharge rate calculations via unsaturated zone modeling. The groundwater composition in June 2007 exhibited elevated nitrate (NO ₃ ^? ) and chloride (Cl^?) concentrations due to fertilizer leaching from the top soil. The spatial distribution of NO ₃ ^? and Cl^? was heterogeneous and the concentration decreased during the monitoring period, with NO ₃ ^? attenuation (below 10?mg/l) after 650?days. A transient groundwater flow and contaminant transport model was calibrated versus observed heads and NO ₃ ^? and Cl^? concentrations. Cl^? was used as environmental tracer to quantify groundwater flow velocity and it was simulated as a conservative species. NO ₃ ^? was treated as a reactive species and denitrification was simulated with a first order degradation rate constant. Model calibration gave a low denitrification rate (2.5e^?3 mg-NO ₃ ^? /l/d) likely because of prevailing oxic conditions and low concentration of dissolved organic carbon. Scenario modeling was implemented with steady state and variable flow time discretization to identify the mechanism of NO ₃ ^? attenuation. It was shown that transient piezometric conditions did not exert a strong control on NO ₃ ^? clean up time, while transient recharge rate did, because it is the main source of unpolluted water in the domain.     

Assessment of inoculation methods to identify resistance to Fusarium crown rot in wheat

Journal of Plant Diseases and Protection - Crown rot, caused by Fusarium culmorum and Fusarium pseudograminearum, is one of the most pervasive diseases of wheat throughout the world. Fusarium...     

Field performance of Lynfield and McPhail traps for monitoring male and female sterile Bactrocera tryoni (Froggatt) and wild Dacus newmani (Perkins)

BACKGROUND: McPhail traps, baited with protein food lure, are used worldwide for surveillance of many species of fruit flies. Queensland fruit fly (Qfly) Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) is a native Australian fruit fly and normally monitored using Lynfield traps baited with cuelure. On some occasions, McPhail traps with wet food lures are deployed to detect female flies or to find the incursion epicentre. This paper reviews field results on the merits of Lynfield and McPhail traps for detection of male and female Qfly. RESULTS: Following release of equal numbers of sterile males and females, Lynfield traps baited with cuelure captured more Qfly males than protein autolysate or orange concentrate in McPhail traps. Significantly more male than female Qfly were captured in McPhail traps baited with protein autolysate or orange. There was no significant difference between orange concentrate lure and protein autolysate lure in attracting either males or females. Another Australian native fruit fly, Dacus newmani (Perkins), was attracted to cuelure in Lynfield traps but not to either lure in McPhail traps. CONCLUSIONS: The data obtained run counter to the reputation of McPhail traps baited with protein autolysate or orange concentrate as a specialist lure/trap combination for female Qfly. Copyright © 2010 Society of Chemical Industry     

The Quantum Event of Oceanic Crustal Accretion: Impacts of Diking at Mid-Ocean Ridges

Seafloor diking-eruptive events represent the irreducible, quantum events of upper oceanic crustal accretion. They record events by which a large portion of the oceanic crust has formed through geological history. Since 1993, the U.S. Navy's real-time Sound Surveillance System has allowed location of ongoing acoustic signatures of dike emplacement and basalt eruptions at ridge crests in the northeast Pacific. These diking-eruptive events trigger a sequence of related, rapidly evolving physical, chemical, and biological processes. Magmatic volatiles released during these events may provide nutrients for communities of subseafloor microorganisms, some of which thrive in high-temperature anaerobic environments. Many of the organisms identified from these systems are Archaea. If microorganisms can thrive in the water-saturated pores and cracks within deep, volcanically active portions of our planet, other hydrothermally active planets may harbor similar life forms.     

Long-term study of the reproductive timing of the Neotropical catfish Iheringichthys labrosus (Lütken, 1874): Influence of temperature and river discharge

Unravelling the effect of climate variability on species biology has been one of the main goals of ecological studies. Environmental factors such as river discharge and temperature have being proposed as triggers of reproductive cycle in fish. In temperate climates, fish reproduction is affected mainly by temperature, while is influenced by flood pulses in large tropical rivers. We evaluated the influence of temperature and river discharge as triggers of Iheringichthys labrosus’ reproduction. We studied the following reproductive variables: gonadosomatic index (GSI), hepatosomatic index (HSI) and condition factor (K). Females of I. labrosus were examined in a time series of ten years along three sites located in Lower Uruguay River at the beginning (last week of November-first week of December, spring) and by the end of the reproductive period (middle-end of April, autumn). Generalised linear models detected a positive effect of mean winter temperature and site on the spring mature female GSI. Site was significant in addition to the interaction between temperature and site. Moreover, the effect of winter temperature was stronger than water discharge in triggering reproductive timing of I. labrosus, contrary to the model proposed for other species in tropical systems. Additionally, a literature review suggested a latitudinal gradient on reproduction, occurring earlier and prolonged with decreasing latitude (and increasing temperature). In this study, we stated the effect of temperature on the life history in a Neotropical fish using a multifaceted approach, particularly important in the current context of global climate warming.