Permanent Tracks Research Articles

Controlled traffic farming and field traffic management: Perceptions of farmers groups from Northern and Western European countries

As farming machinery size and weight increases, soil compaction continues to threaten mechanized agriculture. Controlled Traffic Farming (CTF) minimizes soil compaction in the crop zone by restricting traffic to permanent tracks. The adoption of CTF in Europe is low. This study enhances the understanding of farmers' needs and perceptions concerning the application of CTF by analyzing survey data from 103 farmers sampled from 8 European countries. The study adopted a descriptive approach to data analysis. Awareness about traffic-induced soil compaction is high among surveyed farmers and there are positive perceptions about the potential of CTF. The major factors limiting adoption of CTF appear to be: lack of compatibility in machinery and Global Navigation Satellite Systems (GNSS) by different manufacturers; expense (equipment purchase, Real-time Kinematic (RTK) signal, machinery modification); lack of demonstrated benefits under local conditions; incomplete knowledge of research findings and decision support tools; and a perception that CTF is not for small farms. The following interventions are suggested for future development and use of CTF: a shift towards lighter, simpler, adaptable, and energy effective machinery; adapted market models for cost-effective provision of basic services; demonstration of costs and benefits under local conditions in tandem with demand-driven decision support tools as well as standardization of equipment and positioning systems.

Responses of small vertebrates to linear clearings in a South Australian woodland

AbstractThis work assesses whether the width and “permanence” of linear clearings affects the distribution and movement patterns of small, terrestrial vertebrates in a native South Australian woodland. We examined the influence of narrow (1.5 and 4.2 m), non‐permanent seismic exploration tracks; and wide (6–7 and 12–15 m), permanent fire tracks. There were 1,007 captures of 14 species (four amphibians, six reptiles, four mammals) from 18,000 trap days/nights across 15 sites. Total species richness was highest adjacent to 6–7 m wide permanent tracks (8.3) and lowest in areas without clearings (5.3). There was heterogeneity of captures between track types (p < 0.008), species (p < 0.001), and species by track type (p < 0.001). Antechinus flavipes was most abundant adjacent to both types of permanent tracks, probably as a result of increased habitat complexity at these sites. Twenty‐four percent of movements by recaptured A. flavipes involved track crossings. Animals crossed all track types; nevertheless, individuals were more likely to be recaptured on the same side of a track. Individuals were less likely to cross permanent tracks (p = 0.025 for 6–7 m and p = 0.008 for 12 to 15‐m‐wide tracks), with females being particularly inhibited. Although 11 % of 56 recaptured Rattus spp. had crossed a track, no individuals crossed the 12 to 15‐m permanent tracks. In the habitat type studied here, narrow seismic lines may have a slightly positive effect on some ground‐dwelling vertebrates, and do not appear to substantially inhibit movement. However, there is a need to carefully manage permanent tracks, which could isolate faunal populations.

Site impact after motor-manual and mechanised thinning in Mediterranean pine plantations

The study determined the site impacts of motor-manual and fully mechanised whole tree harvesting, as applied in the thinning of young pine plantations on the Tuscan coastline. The thinning was applied with selection criteria, removing between 36 and 39% of the tree number. The frequency of tree wounding was 1.5 and 5%, respectively for the mechanised and the motor-manual treatment. Wounds inflicted by the mechanised system were also four times smaller than those inflicted by the motor-manual system. The superior performance of the mechanised system was ascribed to its better capacity for handling cut trees. Soil bulk density increased by 3% and 6% after motor-manual and mechanised harvesting, respectively. The increase was small but significant, whereas the difference between treatments was not significant. Machine traffic resulted in a significant increase of CO2 concentration in the soil air, which was 0.4% in the undisturbed control plots and 0.8% in the machine tracks. No significant difference was found between the treatments. The CO2 concentration in the machine tracks was very near to the 1% critical threshold, beyond which biological activity is so constrained that soil recovery may be significantly delayed. When repeated entries are necessary, it is best to avoid creating new tracks by restricting traffic to designated permanent tracks. Properly applied mechanised harvesting does not cause heavier soil impacts than traditional motor-manual harvesting, but it results in a much lower stand damage. Foresters may support the introduction of mechanised harvesting, to the advantage of productivity, economics and work safety.

Do utility corridors affect movements of small terrestrial fauna?

Linear forest clearings created by utility corridors have the potential to fragment landscapes, create edge effects and isolate populations of plants and animals. Here, we investigated the impact of utility corridors on small terrestrial fauna inhabiting Nangwarry Native Forest Reserve, south of Penola in south-eastern South Australia. Twelve sites straddling linear clearings of two widths (1.5 and 4.2 m) were surveyed over 2 years with 53 traps arranged as five transects at each site. This resulted in a total of 933 captures of 18 vertebrate species, including four amphibians, eight reptiles and six mammals. Propensity for capture near edges v. interiors, distances moved between recaptures and willingness to cross linear clearings varied among species, and was not related to taxa groups. For example, the small skink Bassiana duperreyi was extremely mobile and crossed tracks regularly. At the other extreme, the frog Neobatrachus pictus was more likely to be caught on interior transects and was never recorded moving between captures. The small dasyurid Antechinus flavipes was the most regularly caught species, and made both short- (<50 m) and long-distance (>1500 m) movements, with longer moves made by dispersing juveniles. Movements by this species often involved clearing crossings, although these were more likely when time between recaptures was longer, particularly for females. However, the overall rate of crossings for this species was not different from that expected if movements were random. In conclusion, the relatively narrow utility corridors studied here did not appear to affect the mobility of the majority of vertebrates significantly, with approximately half of the 85 movements recorded being of animals crossing a clearing, and no significant difference between the proportion crossing the wider (4.2 m) and the narrower (1.5 m) clearings. The present study is one of only a handful investigating movement patterns in reptiles and amphibians, particularly in relation to disturbances. However, sample sizes were small for some species, and future work should focus on those species that look to be either particularly mobile or sedentary, and encompass responses to the wider (up to 15 m) permanent tracks in the region.

Left ventricular diameter via permanent pacing lead-based sonomicrometry tracks the development and recovery of congestive heart failure in dogs

Left ventricular diameter via permanent pacing lead-based sonomicrometry tracks the development and recovery of congestive heart failure in dogs

Heavy Ion Nuclear Tracks—An Emerging Technology

Nuclear tracks are a logical extrapolation of the principles of cloud and bubble chamber onto solids. Besides their well‐known application in particle detection, in solids a completely new aspect arises, the generation of extremely fine permanent tracks, which can be transformed into open channels. Nuclear tracks are therefore a unique single‐particle structuring tool. Applications comprise (i) single hole membranes for particle counting and sizing, (ii) manufacture of microfilters with very uniform hole sizes, (iii) modification of magneto‐optic materials for application in display memories, and (iv) micromachining\\ of surfaces.

Laser-stimulated atomic migration

The effects of stimulated Raman scattering (SRS) and of infrared (IR) absorption on the scattering at defects leading to atomic migration in solids is evaluated in detail for certain systems. \DeltaE/kT \approx \sum u_{ic}^{2}/\langleu_{i}u_{i}\rangle , where \DeltaE is the activation energy, u ic is the many-body critical displacement in a migration event, and \langleu_{i}u_{i}\rangle is the equal-time correlation function including anharmonic terms. Using the equal-time correlation for the defect lattice in the harmonic approximation, we get \DeltaE/kT_{eff} \propto 1/\sum h[2(n_{s} + n_{e}) + 1] where T eff includes both n e and n s the externally and thermally excited phonon numbers, respectively. The phonon rate density required for an observable effect of SRS or IR absorption on diffusion in solids is n_{e}^{(c)}c_{s}/V \approx 10^{26} - 10^{27} phonons/s.cm2, where n_{e}^{(c)} is a critical number of high wave-vector laser-stimulated phonons, c s , is the sound velocity, and V, the volume per atom. In KCI at 110 K, theory shows that n_{e} = 0.2 can produce a factor of 10 effect on the reorientation of Na:F A centers. Anharmonic effects on \langleu_{i}u_{i}\rangle were calculated and numerical estimates indicate that they would be experimentally observable for large n e . It is found that some of the effects reported here probably contribute, in part, to the permanent damage tracks caused by high-power laser beams in solids and provide an internal source for the initiation of microcracks. In addition, the direction of the stimulated phonon wave vector is shown to produce a directional effect in the control of atomic migration.

Fission fragment tracks in semiconducting layer structures

Abstract Fission fragment irradiation of a number of semiconducting materials establishes that permanent tracks are formed only when the conductivity is ≲2 × 103 (ohm-cm)−1. The intermittent nature of particle tracks is a characteristic of layer structures and further analysis confirms that there is one ‘defect’ per sandwich plane crossed by the fission particle. The intermittency is ascribed to the reduced energy loss of the fission fragment when it travels in the interplanar channel.