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Conference abstract, 2004

Steaming soil in narrow strips for intra-row weed control in sugar beet

Hansson, David; Svensson, Sven-Erik

Abstract

The objective was to study the weed control effect and the energy use when soil was steamed in narrow strips before sowing. The experiment was carried out on a sandy soil on an organically cultivated field in the southern part of Sweden (Österlen). The field was sown with sugar beet a couple of hours after the treatment. Annual weeds were predominant in the experiment, with the main species observed being Senecio vulgaris (L.), Chenopodium album (L.) Solanum nigrum (L). and Solanum physalifolium (Rusby). Treatments were performed using tractor-drawn steaming equipment from Regero (France) with a 700 kW diesel boiler to heat the water. The hot steam was conveyed to nine applicators (9 rows). Each applicator heated a section of the soil 0.14 m wide and 0.04-0.05 m deep. The total working width for the equipment was 5.10 m. The amount of steam applied per hectare was adjusted by varying the tractor travel speed. Dose-response relationships were described in order to estimate the effective energy use and effective travel speed of steam treatment. The soil temperature was 70 °C to 80 °C during the treatment. Preliminary results indicate that steam treatment can control S. vulgaris and C. album. It was not possible to show a significant weed control effect on S. nigrum, S. physalifolium and Fallopia convolvulus (L.) at the energy doses studied. One explanation for the insignificant effect may be that the soil temperature did not reach 70-80 °C in all parts of the treated soil volume, i.e. in the central part of the volume. The energy dose required to achieve a 90% reduction in plant number (LD90) was 850 L diesel ha-1. The steam-applicators used in the experiment were prototypes, i.e. there can be a great potential to decrease the energy use by technical development of the applicators. The steam treatment made it possible to reduce the working-hours for manual weed control (hoeing) from approximately 110 h ha-1 to 60 h ha-1. The cost to treat one hectare is estimated to 7500 SEK (830 €, 2003 price level) with the equipment from Stockholmsgården, under following circumstances. Investment 300 000 SEK, 79 L diesel oil h-1, 4 SEK L-1 diesel oil, driver 150 SEK h-1, tractor 100 SEK h-1, capacity 0.1 hectare h-1 and 20 hectare year-1. Decreasing the treated strip to half of the width will double the capacity and decrease the cost to approx. 4900 SEK hectare-1

Published in


Publisher: EWRS (EUROPEAN WEED RESEARCH SOCIETY )

Conference

6th EWRS Workshop on Physical and Cultural Weed Control