Year-round variability of field-saturated hydraulic conductivity and runoff in tilled and grassed vineyards

The soil management adopted in vineyard inter-rows has a great influence on soil hydraulic properties, and, consequently, on runoff at the field scale. Conventional management with tillage is adopted by vine-growers to improve the soil water recharge during winter. Nevertheless, this practice is known to increase runoff and soil erosion in steep areas, especially in mechanized vineyards, thus grass cover is adopted to reduce these negative impacts. The year-round values of field-saturated hydraulic conductivity and of the field-scale runoff were measured in vineyard plots from November, 2012 to March, 2016 in the Alto Monferrato vine-growing area (Piedmont, NW Italy). Field-saturated hydraulic conductivity values were obtained by 110 infiltration measurements. The tests were carried out by adopting the Simplified Falling Head methodology in two adjacent vineyards plots, where inter-rows were managed with conventional tillage (CT) and grass cover (GC), respectively. The runoff, the soil temperature and the soil water content in the two plots have also been recorded. As it was expected, the tillage increased the field-saturated hydraulic conductivity with respect to the plot with permanent grass cover. However, this effect was only temporary, since a decrease in field-saturated hydraulic conductivity was observed as a consequence of cumulative precipitation and tractor passages after the tillage operations. The field-saturated hydraulic conductivity ranged between 9 and 9119 mm h-1 in the tilled plot and between 4 and 1775 mm h-1 in the plot with grass cover. The response of the plots to precipitation events, in terms of runoff also varied considerably. Generally, during most of the events, the runoff in the tilled plot resulted higher (up to nearly 20 times) than in the grassed one. The grass cover was less effective in occasion of large precipitation events during the wet seasons than in other months

Chipping machines: disc and drum energy requirements

Air pollution and fossil fuel reserves exhaustion are increasing the importance of the biomass-derived products, in particular wood, as source of clean and renewable energy for the production of electricity or steam. In order to improve the global efficiency and the entire production chain, we have to evaluate the energetic aspects linked to the process of transformation, handling and transport of these materials. This paper reports results on a comparison between two chippers of similar size using different cutting technology: disc and drum tool respectively. During trials, fuel consumption, PTO torque and speed, processing time and weight of processed material were recorded. Power demand, fuel consumption, specific energy and productivity were computed. The machine was fed with four different feedstock types (chestnut logs, poplar logs, poplar branches, poplar sawmill residues). 15 repetitions for each combination of feedstock-tool were carried out. The results of this study show that the disc tool requires, depending on the processed material, from 12 to 18% less fuel per unit of material processed than the drum tool, and consequently, from 12 to 16% less specific energy. In particular, the highest difference between tools was found in branches processing whereas the smallest was in poplar logs. Furthermore the results of the investigation indicate, that, in testing conditions, the productivity of drum tool is higher (8%) than disc tool

Effect of densification conditions on specific energy requirements and physical properties of compacts made from hop cone

Hop cones, due to their essential flavor, are one of the four main ingredients for beer production. The paper reports the results on an investigation of the densification process of hop cones. This experiment investigated (i) the effects of compression pressure in the range of 40 to 80 MPa and pressure application time in the range of 10 to 40 s on the final density and durability of the compacts made from hop cones and ii) the specific compression energy required for the process. The specific compression energy requirements to compact hop cones ranged from 14.20 to 24.48 kJ kg−1. The final compact density values ranged from 515.2 to 876.6 kg m−3, while the durability percentage calculated ranged from 71% to 91%. The obtained results highlighted that compression pressure—in the range of 40–80 MPa—significantly affects the specific compression energy requirements, the final density and the durability of the produced compacts. In this experiment, pressure application time plays a key role in determining compacts density, while did not affect durability and compression energy requirements. Considering the specific compression energy values calculated in this experiment, it can be stated that the pressure agglomeration method described to compact hop cones is more efficient than pelletizing process which is typically characterized by specific energy values ranging from 19 to 90 kJ kg−1

Ultra-thin clay layers facilitate seismic slip in carbonate faults

Many earthquakes propagate up to the Earth's surface producing surface ruptures. Seismic slip propagation is facilitated by along-fault low dynamic frictional resistance, which is controlled by a number of physico-chemical lubrication mechanisms. In particular, rotary shear experiments conducted at seismic slip rates (1 ms(-1)) show that phyllosilicates can facilitate co-seismic slip along faults during earthquakes. This evidence is crucial for hazard assessment along oceanic subduction zones, where pelagic clays participate in seismic slip propagation. Conversely, the reason why, in continental domains, co-seismic slip along faults can propagate up to the Earth's surface is still poorly understood. We document the occurrence of micrometer-thick phyllosilicate-bearing layers along a carbonate-hosted seismogenic extensional fault in the central Apennines, Italy. Using friction experiments, we demonstrate that, at seismic slip rates (1 ms(-1)), similar calcite gouges with pre-existing phyllosilicate-bearing (clay content ≤3 wt.%) micro-layers weaken faster than calcite gouges or mixed calcite-phyllosilicate gouges. We thus propose that, within calcite gouge, ultra-low clay content (≤3 wt.%) localized along micrometer-thick layers can facilitate seismic slip propagation during earthquakes in continental domains, possibly enhancing surface displacement

It does not occur by chance: a mediation model of the influence of workers' characteristics, work environment factors, and near misses on agricultural machinery-related accidents

Agriculture is among the most hazardous productive sectors, and farm machinery is a major source of injury. In the present study, a mediated model was used to test the role played by workers’ characteristics, work environment factors, and near misses in predicting agricultural machinery-related accidents in a sample of Italian users (n = 290). Hours worked per week (via the mediation of an adverse work environment) showed a positive association and years of work experience (via the mediation of risk perception) showed a negative association with the probability of being involved in a near miss, which in turn showed a positive association with the probability of being involved in a machinery-related accident. Implications for tailored preventive interventions are discussed

Falls From Agricultural Machinery: Risk Factors Related to Work Experience, Worked Hours, and Operators' Behavior

Objective: We investigated the risk factors for falls when egressing from agricultural tractors, analyzing the role played by worked hours, work experience, operators' behavior, and near misses. Background: Many accidents occur within the agricultural sector each year. Among them, falls while dismounting the tractor represent a major source of injuries. Previous studies pointed out frequent hazardous movements and incorrect behaviors adopted by operators to exit the tractor cab. However, less is known about the determinants of such behaviors. In addition, near misses are known to be important predictors of accidents, but they have been under-investigated in the agricultural sector in general and as concerns falls in particular. Method: A questionnaire assessing dismounting behaviors, previous accidents and near misses, and participants' relation with work was administered to a sample of Italian tractor operators (n = 286). Results: A mediated model showed that worked hours increase unsafe behaviors, whereas work experience decreases them. Unsafe behaviors in turn show a positive association with accidents, via the mediation of near misses. Conclusions: We gave a novel contribution to the knowledge of the chain of events leading to fall accidents in the agricultural sector, which is one of the most hazardous industries. Applications: Besides tractor design improvements, preventive training interventions may focus on the redesign of the actual working strategies and the adoption of engaging training methods in the use of machinery to optimize the learning of safety practices and safe behavior

A method to evaluate the perceived ease of use of human-machine interface in agricultural tractors equipped with Continuously Variable Transmission (CVT)

At the end of the 20th century the adoption of the Continuously Variable Transmission (CVT) was one of the disruptive technological advances in agricultural tractors. Several changes in the Human Machine Interface (HMI) of the tractor cab have been introduced to accommodate this technology. HMIs are known to raise issues about their ease of use; however, this topic has been under-investigated in the agricultural sector. The present study introduces a method to investigate the perceived ease of use of the HMI of agricultural tractors equipped with technological innovations. The HMI required to manage a CVT tractor was evaluated by sixteen tractor drivers (8 novices and 8 experts). During the first contact with the machine and after having performed two targeted tasks with the tractor, participants filled in a questionnaire about the ease of use of the controls and of the touch-screen display, and evaluated the general perception of ease of use, safety, quality and solidity of the machine. The trial pointed out some significant differences between novices and experts, thus confirming the validity of the proposed method. In particular, novice users showed some difficulties when interacting for the first time with the HMI of the CVT tractor working station, whereas experts did not report similar difficulties. Thus, expertise seems to play a role in determining the quality of the interaction with the HMI. Training interventions should be designed to help novices in increasing their expertise effectively, avoiding effort and errors and improving user’s comfort and system performance