Automated,variable speed PTO for a plot-sized potato harvester

A single-row potato harvester, commonly used in small plot research, was modified to allow the operator to set the harvester chain speed independently of both the ground speed and the tractor engine speed. The modification has greatly increased the utility of the harvester for small research plots.     

Development of a vibratory potato digger for small farms

The performance of the vibrating blade, attached to a two-wheeled and hand-steered 7.35 kw tractor, was improved by increasing frequency while reducing amplitude. Increased frequency assisted the travel speed of the machine by better feeding of materials into the digger blade and by enhancing soil separation. Vibrations with higher amplitude and frequency allowed the machine to travel faster for a given engine and transmission speed of tractor. Slippage of the wheels with lower amplitude and frequency was the major factor limiting the travel speed. The effects of vibrations on the unrecovered and damaged potatoes were not clear. The sum of unrecovered and damaged potatoes ranged from 1.25 to 8.35 percent It was found that the total acceleration of the vibrating blade was approximately proportional to the amplitude and to the square of frequency. A parameter ρ (a ratio of acceleration of the vibrating blade to the travel speed of tractor) was introduced and found to evaluate the performance of the blade better than an existing parameter λ     

Screening potato cultivars for common scab of potato in a naturally infested field

Summary Twenty seven cultivars of potato were screened for common scab grown in a commercial field in two successive years (1996–97 and 1997–98). Eight cultivars were least susceptible and the others ranged from medium susceptible to very highly susceptible. None of the cultivars was resistant. Most showed a stable resistance reaction in both years.     

The effect on annual dry matter yield of using a hand-controlled mower or a plot harvester for cutting herbage on small-plot trials

A sward of S24 perennial ryegrass was sampled at 4-weekly intervals over two seasons with either a Haldrup 1500 plot harvester or a hand-controlled mower fitted with a fixed reciprocating cutter bar. Plot dimensions were adjusted to the width of the machines'cutter bars (1.5 m and 1.0 m respectively) so that there were no discard areas to require removal. Plots were cut either once, or twice in opposite directions. After cutting, residual stubble heights and the proportion of ground surface covered by leaf laminae were recorded.
Mean annual dry matter (DM) yields recorded in ten harvests made each year showed no overall significant difference between the machines. However, previous practice had been to sample plots with one pass of the hand-controlled mower and to trim the sampled area while removing the usual discard strips. The comparison of annual DM yields from one cut taken with the Haldrup or from two cuts taken with the mower, but with the yield at the second cut excluded, showed a mean advantage of 1.55 t DM ha⁻¹ a⁻¹ for the Haldrup technique or a 14.6% increase over previous practice.
Cutting twice significantly ( P <0.001) reduced herbage production by a mean of 0.85 t DM ha⁻¹ a⁻¹, mean residual stubble height by 9.8 mm and the proportion of ground covered by leaf laminae by 9.8%. Provided that judgment is exercised when planning treatments and layout of trials, it is concluded that the Haldrup 1500 plot harvester is a valuable labour-saving tool. However, DM yields from trials cut frequently with this machine are likely to exceed those from similar trials cut with a hand-controlled mower, following the usual G.R.I. Staff (1961) technique.     

European Association for potato research

Ohne Zusammenfassung

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European Association for potato research

     

European association for potato research

Ohne Zusammenfassung

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European association for potato research

     

An agenda for future potato research

Summary The world is changing, and the rate of change is accelerating, nowhere moreso than in the pace of scientific discovery and the advance of technology. The last thirty years have also seen substantial global changes in potato production which are likely to continue if current projections are correct. Climate change is bound to affect local weather patterns, which will influence both the epidemiology of pests and pathogens and broaden their geographic range. An agenda for future research will of necessity include much of the current agenda; research into more sustainable systems; research into new and novel resistances to biotic and abiotic constraints, combining modern cell and molecular-based technologies with classical breeding approaches and research into the genetic and biochemical bases of low temperature sweetening and dormancy control, that should lead to varieties with superior storage characteristics, particularly for processing. However, a future agenda has to retain some flexibility and a component of speculative research. Perhaps potatoes could become a source of industrial feedstock or pharmaceuticals, perhaps there is a place for cultivars produced by botanic seed in Europe? The exciting thing about research is that we cannot always predict where it will lead, and a future agenda must not curb the enthusiasm of any young scientist by too rigidly adhering to that suggested here. it is essential that scientific options are kept open.     

A bulk potato trailer for research plots

A bulk trailer was designed and evaluated which facilitates the handling of potatoes from field plots to storage. To meet the requirements of harvesting field plots, the trailer was designed to accommodate both manual and mechanical harvesting. Design techniques, such as incorporating framing members into the shape of the bulk body, were utilized in order to develop a low profile trailer. This was also made possible by the use of cantilevered tandem axles. The resulting trailer had a loading height at either 1270 or 1575 mm with a maximum capacity of 6 tonnes. Tests which were conducted to measure the mechanical injury caused to the potatoes indicated that the average damage index was 166.2 which included both the harvesting and transportation.     

An approach to field screening potato genotypes for potato leaf roll virus resistance

Eight potato cultivars and two advanced breeder selections were assessed for field resistance to the potato leaf roll virus (PLRV) following field exposures in which PLRV-infected Russet Burbank plants were used as inoculum sources within treatments. This screening protocol provided consistent PLRV resistance ratings despite year-to-year variation in PLRV pressure. Secondary disease incidence based on enzyme-linked immunosorbent assay (ELISA) of foliage from tuber progeny ranged from 0–87% in 1990 and 0–67% in 1991, and was consistent with reported PLRV resistance ratings for eight of ten genotypes. Agreement between visual assessment and ELISA on plants from harvested tubers was 94% in 1990 and 83% in 1991, for all genotypes. However, agreement data were inconsistent from year-to-year, with the exception of three genotypes. In both years, current season infection, based on ELISA of foliage, was detected in less than two percent of the plants and, was inadequate as a measure of secondary PLRV incidence. Green peach aphid (GPA) populations did not differ among genotypes at sampling times during the season, but the PLRV concentration in GPA colonizing Russet Burbank plots was significantly higher than in GPA colonizing any other genotype.     

Techniques for successful field seeding of true potato seed

Crops of potatoes were successfully grown during each of 7 yrs from botanical seed planted directly into fields. During this period a total of 8 ha of direct-seeded potatoes was grown in 27 trials involving several soil types and several planting, cultural, and irrigation methods. Methods of seed production, extraction, treatment, and planting were developed along with methods of weed and insect control and methods of caring for growing seedlings so they would produce good yields of tubers, many of which were of commercial size and quality and very useful in a breeding program.     

Report of the committee on standardization of field plot technique

American Journal of Potato Research -