Abstract: In this study, we investigated the effects of different feed structures and beddings on the spread of C. jejuni in broiler flocks, and the effect on the cecal microbiota. Broiler chickens raised in 24 eight-bird group cages on either rubber mat or wood shavings were fed either a wheat-based control diet (Control), a diet where 50% of the ground wheat was replaced by whole wheat prior to pelleting (Wheat), or a wheat-based diet, such as the control diet diluted with 12% oat hulls (Oat). Samples from the cloacal mucosa of all birds were taken daily for C. jejuni quantification and cecum samples were collected at the end of the experiment for C. jejuni quantification and microbiota analyses. We have shown a statistically significant effect of increased feed structure on the reduced spread of C. jejuni in chicken flocks, but no significant differences were detected between types of structure included in the feed. No significant changes in the dominating microbiota in the lower lower gastrointestinal (GI) tract were observed, which indicates that feed structure only has an effect on the upper GI tract. Delaying the spread of C. jejuni in broiler flocks could, at time of slaughter, result in fewer C. jejuni-positive broilers.
Abstract: Sediment generated by interrill erosion is commonly assumed to be enriched in soil organic carbon (SOC) compared to the source soil. However, the reported SOC enrichment ratios (ERSOC) vary widely. It is also noteworthy that most studies reported that the ERSOC is greater than unity, while conservation of mass dictates that the ERSOC of sediment must be balanced over time by a decline of SOC in the source area material. Although the effects of crusting on SOC erosion have been recognized, a systematic study on complete crust formation and interrill SOC erosion has not been conducted so far. The aim of this study was to analyze the effect of prolonged crust formation and its variability on the ERSOC of sediment. Two silty loams were simultaneously exposed to a rainfall simulation for 6 h. The ERSOC in sediment from both soils increased at first, peaked around the point when steady-state runoff was achieved and declined afterwards. The results show that crusting plays a crucial role in the ERSOC development over time and, in particular, that the conservation of mass applies to the ERSOC of sediment as a consequence of crusting. A “constant” ERSOC of sediment is therefore possibly biased, leading to an overestimation of SOC erosion. The results illustrate that the potential off-site effects of selective interrill erosion require considering the crusting effects on sediment properties in the specific context of the interaction between soil management, rainfall and erosion.
Abstract: The benefits of biochar to soils for agricultural purposes are numerous. Biochar may be added to soils with the intention to improve the soil, displace an amount of conventional fossil fuel based fertilizers, and sequester carbon. However, the variable application rates, uncertain feedstock effects, and initial soil state provide a wide range of cost for marginally improved yield from biochar additions, which is often economically impracticable. The need for further clarity on optimizing biochar application to various crop yields is necessary if it is to gain widespread acceptance as a soil amendment.
Abstract: Hygiene management is essential for rearing Campylobacter free broiler flocks. In this study, several hygiene factors (e.g., thinning, water supply, stable cloths, stable condition, stable environment, etc.) are categorized and aggregated in a developed risk priority number (RPN). This number is measuring the quality of hygiene management of a broiler farm with one single value (range: 801–4005 points), the higher the RPN, the better is the hygiene status. The distribution of the values is left skewed and none of the 53 examined Austrian broiler farms reached the maximum. Cecal samples (n = 610) from broilers at the point of slaughter determined the Campylobacter status of the farms. Farms with a high RPN consistently produced more Campylobacter free batches than farms with a low RPN. Ranking of the broiler farms based on their RPN was significantly correlated with their microbiological results for Campylobacter detection (Spearman’s correlation coefficient = 0.646). The risk priority number is an easy tool for the assessment and measurement of the hygiene management system at a broiler farm. Besides the educational benefits of the RPN, benchmarking against the mean value or the maximum is possible.
Abstract: In recent decades, the off-site transport of sediment and nutrients from agricultural land into the neighbouring natural and built environment has become a more pressing environmental sustainability issue than the on-site threats of soil erosion in many of the world’s temperate regions. In the temperate region of Northern Ireland, recent studies have highlighted the off-site issue of soil erosion by water in the present day, and projected that the problem may become more widespread and serious in a changing climate. This review paper examines how this problem is being managed in the present day, and draws on examples of policy in other countries to consider how the role of policy needs to be modified for more effective management. Farmers are generally not adhering to present-day policy and “keeping their land in good agricultural and environmental condition”. A range of suggested changes in policy and practice is offered, ranging from educating farmers on erosion mitigation and remediation to developing specific policies aimed at targeting soil erosion and conservation as their sole objective. An increase in the evidence base from measured erosion rates in the field is postulated to be the most likely route to achieving policy changes.
Abstract: In tropical countries soil erosion is often increased due to high erodibility of geologically old and weathered soils; intensive rainfall; inappropriate soil management; removal of forest vegetation cover; and mining activities. Stream ecosystems draining agricultural or mining areas are often severely impacted by the high loads of eroded material entering the stream channel; increasing turbidity; covering instream habitat and affecting the riparian zone; and thereby modifying habitat and food web structures. The biodiversity is severely threatened by these negative effects as the aquatic and riparian fauna and flora are not adapted to cope with excessive rates of erosion and sedimentation. Eroded material may also be polluted by pesticides or heavy metals that have an aggravating effect on functions and ecosystem services. Loss of superficial material and deepening of erosion gullies impoverish the nutrient and carbon contents of the soils; and lower the water tables; causing a “lose-lose” situation for agricultural productivity and environmental integrity. Several examples show how to interrupt this vicious cycle by integrated catchment management and by combining “green” and “hard” engineering for habitat restoration. In this review; we summarize current findings on this issue from tropical countries with a focus on case studies from Suriname and Brazil.