Design of terrace drainage networks using UAV-based high-resolution topographic data

Hillslope viticulture has a long history in Mediterranean Europe, and still holds important cultural and economic value. Steep hillsides have widely been levelled by terraces, in order to control surface water flow and facilitate cultivation. However, under unsustainable management and growing rainfall aggressiveness, terraced vineyards have become one of the most erosion-prone agricultural landscapes. The Valcamonica valley in Lombardy (Italy) presents a typical example of an ancient wine production region where rural land abandonment has previously caused widespread degradation of the traditional terracing systems. Recently, a local revival of wine production led to restoration plans of the terraces and their drainage functioning, to safeguard productivity and hydrogeologic safety. In this study, an Unmanned Aerial Vehicle (UAV) survey was carried out to reconstruct an accurate and precise 3D terrain model of a Valcamonica vineyard. through photogrammetry. The resulting high-resolution topographic data allowed insights of surface flow-induced soil erosion patterns based on the Relative Path Impact Index (RPII). Three diverse drainage networks were designed and digitally implemented, allowing scenario analysis of the costs and benefits in terms of potential erosion mitigation. The presented methodology could likely improve the time-efficiency and cost-effectiveness of similar restoration plans in degraded landscapes

Impact of mechanisation on soil loss in terraced vineyard landscapes

Soil loss poses a threat to hilly and mountainous areas, particularly where local economies strongly depend on agricultural production. Among agricultural landscapes, vineyards are responsible for the highest erosion rates, particularly in steep-slope landscapes. The impact of vineyard mechanisation on soil loss is only marginally explored in published literature. This study provides an estimation of the annual soil loss rate by application of the Revised Universal Soil Loss Equation (RUSLE) in 24 terraced vineyards located in north-eastern Italy. Field observations showed that 13 vineyards consisted of fully mechanised fields, 5 vineyards had no form of mechanisation, while in 6 vineyards a mixture of practices was found. Soil erodibility (K factor) was derived for these practices (based on soil characteristics and varying degrees of compaction), while slope length and steepness (LS factors) were calculated from a 1-m LiDAR-based DTM, and remaining factors were based on datasets by the European Soil Data Centre. Mechanised fields showed 29% higher erosion rates than non-mechanised fields (respectively 53.9 and 69.5 t ha-1 y-1), although this is not statistically significant. Still, the direct impact of mechanisation is underestimated in this comparison, due to the predominant steep slopes in the manually cultivated fields. Furthermore, estimated soil loss from mechanised fields in addition to mechanised paths and roads is significantly higher by 37% than non-mechanised fields. This study thus offers an indication of how machinery and related soil compaction and transformation of terraces and infrastructure, increases soil loss risk

The influence of hygroscopic movement on seed dispersal in Daucus carota (Apiaceae)

The influence of hygroscopic movement on seed dispersal in Daucus carota was examined. When relative humidity increases, umbels containing mature fruits close; when relative humidity drops, umbels open. Tests of the effectiveness of smalland large-angled umbels on dispersing seeds under various conditions demonstrate that umbels responding greatly to relative humidity (i.e. opening wide) lose seeds more quickly than do umbels responding little, and do not disperse them as far. As relative humidity increases, number of dispersing seeds drops to near zero. Response to changes in relative humidity within an umbel progressively increases from late August when dispersal begins. Umbels that slowly increase their response retain some seeds that may disperse over snow in winter. Individual variation in response to relative humidity is high among plants beginning dispersal at the same time. This variability is probably maintained by the variable consequences of dispersing seeds at different times.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47734/1/442_2004_Article_BF00541784.pd

Familial Longevity Is Marked by Lower Diurnal Salivary Cortisol Levels: The Leiden Longevity Study

BACKGROUND: Reported findings are inconsistent whether hypothalamic-pituitary-adrenal (HPA) signaling becomes hyperactive with increasing age, resulting in increasing levels of cortisol. Our previous research strongly suggests that offspring from long-lived families are biologically younger. In this study we assessed whether these offspring have a lower HPA axis activity, as measured by lower levels of cortisol and higher cortisol feedback sensitivity. METHODS: Salivary cortisol levels were measured at four time points within the first hour upon awakening and at two time points in the evening in a cohort comprising 149 offspring and 154 partners from the Leiden Longevity Study. A dexamethasone suppression test was performed as a measure of cortisol feedback sensitivity. Age, gender and body mass index, smoking and disease history (type 2 diabetes and hypertension) were considered as possible confounding factors. RESULTS: Salivary cortisol secretion was lower in offspring compared to partners in the morning (Area Under the Curve = 15.6 versus 17.1 nmol/L, respectively; p = 0.048) and in the evening (Area Under the Curve = 3.32 versus 3.82 nmol/L, respectively; p = 0.024). Salivary cortisol levels were not different after dexamethasone (0.5 mg) suppression between offspring and partners (4.82 versus 5.26 nmol/L, respectively; p = 0.28). CONCLUSION: Offspring of nonagenarian siblings are marked by a lower HPA axis activity (reflected by lower diurnal salivary cortisol levels), but not by a difference in cortisol feedback sensitivity. Further in-depth studies aimed at characterizing the HPA axis in offspring and partners are needed