Since the time when plants were first cultivated, one of the most important work in cultivation is weed control. Weeds are plants that do more harm than good to the cultivated plants. For a long time only mechanical methods were used in weed control. Since the middle of the twentieth century mechanical weed control was mostly displaced by the use of synthetic herbicides. Physical methods of weed control were once more investigated and employed in cultivation only in the last few years. This is mainly due to a changed attitude of consumers and cultivators towards chemical plant protection. Moreover, some weeds became resistant to herbicides and the use of chemical plant protection means has been restrained by different laws.
The investigations of this paper are mainly about mechanical methods of inter-row weed control. The main point of the investigations was the concept of the split hoe Weihenstephan, which was developed by WEBER (1997). The split hoe is a combination of duckfoot shares and rotating spring tines. When employed the duckfoot shares cut the roots of the weeds. The rotating tools work in the soil and they throw the weeds and soil against a plastic awning. By this the roots of the weeds and the soil are "split up".
The results of WEBER (1997) were examined in a practical experiment with the split hoe. The experiment took place on the research station Queckbrunnerhof in the state Rheinland-Pfalz. Technical, cultivation-, working- and economical data of the employment of the split hoe were recorded. The row hoe was employed and examined under the same circumstances. The row hoe served as a standard implement of mechanical weed control. By this the results for the split hoe could be compared with data of other implements of mechanical weed control.
The results of WEBER (1997) could mostly be confirmed. The success of mechanical weed control was under equal conditions with the split hoe about 20 to 30 % higher than with the row hoe. High success of weed control could also be achieved with tall weeds, high soil moisture and bad weather conditions. The driving velocity of both implements is on about the same level. Both implements bad about the same impact on the structure of the soil. No difference could be proved on the influence of the two implements on the time needed for hoeing by band.
The costs of both methods of weed control were calculated and compared. Moreover the costs of mechanical weed control were compared with the costs of chemical weed control. The calculation of the costs of chemical weed control was based on literature data.
The costs of hoeing one hectare with the split hoe are higher compared to hoeing one hectare with the row hoe. The costs of the whole weed control of one culture are about the same because the split hoe compensates higher fix and variable costs by a lower amount of employments needed. The costs of the chemical weed control are mostly but not always lower than the costs of mechanical weed control. Mechanical weed control is cheaper if it is possible to achieve low labour costs for hoeing by hand.
The development of a model for calculating an implement-specific figure was another aim of the investigations. The maximum area that could be tilled with the chosen implement of mechanical weed control should be calculated under defined conditions of climate, soil and cultivated plants. To a certain extend the model is based on the model for calculating available field work days, used by WEBER (1997) and HUTNER (1997). The developed model was also examined. The row hoe and carrots were chosen as implement of mechanical weed control and as cultivated plants. The results of the calculation were possible and promising. In the future the model should be investigated more intensely and it could also be further developed.
By the investigation important results of the employment of the split hoe Weihenstephan have been gained. The model seems to give a usable figure for different implements under defined conditions of soil, climate and cultivated plant. Further research and investigation with the split hoe Weihenstephan and the model could increase and complete the knowledge about mechanical weed control under different conditions. This would contribute also to a better understanding of the context within the whole system "mechanical weed control". Hopefully this investigations are another step on that way.
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Since the time when plants were first cultivated, one of the most important work in cultivation is weed control. Weeds are plants that do more harm than good to the cultivated plants. For a long time only mechanical methods were used in weed control. Since the middle of the twentieth century mechanical weed control was mostly displaced by the use of synthetic herbicides. Physical methods of weed control were once more investigated and employed in cultivation only in the last few years. This is m...
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