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- Arvidsson, Johan, et al.
(författare)
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Rubber track systems for conventional tractors : Effects on soil compaction and traction
- 2011
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Ingår i: Soil & Tillage Research. - : Elsevier BV. - 0167-1987 .- 1879-3444. ; 117, s. 103-109
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Tidskriftsartikel (refereegranskat)abstract
- Traditionally, tractors have been built either for tracks or wheels, with tracks mainly on heavy tractors with high power. Today, it is possible to retrofit four separate track units on a conventional agricultural tractor, creating interesting possibilities for agriculture. The objective of the present study was to compare soil compaction and traction for tracks, single and dual wheels mounted on the same tractor type. Measurements were made on two clay soils (Eutric Cambisols) in Sweden in 2009, using an 85kW tractor with a total weight of 7700kg. The rubber track system consisted of four tracks mounted on the conventional wheel axles of the tractor. The measured stresses were similar for the tracks and dual wheels at all depths studied (15, 30 and 50cm), but were considerably higher for the single wheels at all depths. Simulations of soil stresses correlated closely to measured values for the tracks and the dual wheels, but underestimated soil stresses in the topsoil compared to measured values for the single wheel. Bulk density and penetration resistance were consistently highest and saturated hydraulic conductivity lowest after wheeling with single wheels, while there were no statistically significant differences between tracks and dual wheels. With single wheels and the tractor loaded, saturated hydraulic conductivity decreased to 0.01mh-1 from 0.13mh-1 in the control, while bulk density increased from 1.24 to 1.36Mgm-3. The stress distribution in the driving direction was relatively even along the front and rear tracks, which is an advantage compared with a long single track, which often has an uneven longitudinal stress distribution. Slip was significantly higher for the dual and single wheels compared with tracks. To utilise the large contact area of the tracks, the tractor should have a low weight in relation to the engine power. © 2011 Elsevier B.V.
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- Westlin, Hugo, et al.
(författare)
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Alternativa haspelkoncept vid skördetröskning av vitklöver
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The interest for growing grass seed is increasing in Sweden, and there is a potential from several foreign seed companies that would like to establish contacts with growers. Thus, the Swedish growth of grass seed is small compared to other countries in Europe. Growing grass seed is an economical unsure crop, the yield is much controlled by pollination and weather during harvest, as well as access to technical equipment during harvest, drying and storage. One important thing to a successful growth is to reduce losses during harvest. White clover grows low (only 10-15 cm high) and is therefore hard to put up on the header without losses. According to studies as much as 30% of the biological yield can be lost thru wrong settings of combine during harvest. Also, the germination of the seed can be lost due to hard treatment in the combine. Special equipment for grass seed growth is often expensive and is not always a profitable affair for the farmer. Here there are opportunities for improvements of existing techniques. This study aimed to raise profitability for the growth of white clover (Trifolium repens), primary by reducing losses during harvest. The goal was to develop performance enhancing solutions for a traditional combine reel, while at the same time facilitating the driver´s work to create even input in the combine. 4 different alternatives were tested during field trial in the summer of 2020. The results show that a specially designed pickup header gave the lowest losses during racking up white clover. Thus, it had the highest contents of soil minerals in tested seeds. The tested modifications of a traditional reel, reducing rod distance to 6 cm and to replace the rods with a brush, unfortunately did not had the desired effects. For both these alternatives the losses from the header and the losses behind the combine were higher than for a traditional header with rod spacing 12 cm. The brush mounted, with the aim to softly rake the crop up on the header where to soft and were bended, and the desired effect were not achieved.
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