Gräsytors utseende : en utvärdering av klippningsteknik och klippningsrutiner
Hallefält, Fredrik; Hansson, Susanne; Schroeder, Håkan
When choosing methods and technology for maintaining lawns it is necessary to formulate clearly the aim of the maintenance. Today it is difficult to formulate the aim since the terminology is ambiguous and unclear. This report presents different systems for describing green surfaces. The need for maintenance in the form of mowing grass depends on many different factors, both biological and technical. There is a great deal of literature on the biological aspects but relatively little concerning technology and methods for maintenance of grass surfaces. There is also a need for interdisciplinary research to study the relationships between different factors. There are many ways of shortening a grass blade. The most common ones are chopping and cutting, used by machines such as rotary lawn mowers and cylinder lawn mowers. In order to chop off grass efficiently, the peripherical speed of the blade must be approximately 35 m/s. When cutting, the friction between blades and grass must be great enough. The cylinder mower is the most suited to very short and plane grass surfaces: it gives a very level cut and spreads the cuttings evenly if these are not collected. For other types of lawn it is better to use a rotary mower since it is less sensitive to damage than a cylinder mower and can also be used on taller grass. The primary disadvantage of the rotary mower is that it spreads the cuttings unevenly. The rotary mower is an interesting alternative to the rotary lawn mower because of its greater capacity, In general, it is possible to reduce the time required as well as the energy consumed by having sharp and correctly adjusted blades and by keeping the lawn mower in good shape. According to the manufacturer, the cylindrical rotary mower divided in sections can be used as an allround mower for different types of grass, but it has not undergone any thorough testing. Earlier research results with Colonial bentgrass show that grass grows faster if it is mown more often. These trials were carried out with very low heights, between 0.5 and 1.7 cm. Introductory studies carried out at Alnarp in this project suggest that if the cutting height is raised (from x to y), then this will have the opposite effect, that is that growth diminishes. New grass varieties with a slow growth rate also affect the cutting frequency. When evaluating cutting results, it is difficult to measure the quality of a grassed surface with quantitative methods. This report describes some, but there is a large number of parameters that must be taken into consideration and the methods are not always complete. The report describes a simple ball-rolling method, which however only measures one parameter of grass quality which must be weighed together with other qualities. Subjective methods can also be used, but it is difficult to compare results from different judges. In the future, image analysis can be used as a complement to evaluate the quality of a grass surface. In order to calculate mowing costs, we need data that describe capacity under different conditions. Time studies carried out in the project provide a basis for calculating the total time for mowing. In order to use resources efficiently we need to study mowing as a whole. Future research should focus around how green areas should be designed and the consequences on maintenance costs. This could apply to choice of grass type, meadow for example, and its position within a green area.
gräs; gräsklippning; kortgräs; skötsel; gräsklippare; tidsstudier; klipphöjd; klippningsintervall; gräskvalite
Rapport - Sveriges lantbruksuniversitet, Institutionen för lantbruksteknik
Utgivare: Institutionen för lantbruksteknik, Sveriges lantbruksuniversitet
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