Potential of stale seed bed preparation in integrated and organic crop production

This paper reviews a study over six years to assess the potential of stale seed beds in various crops. Using stale seed beds, the farmer has to optimize the combined effect of, firstly, the delaying of the sowing time of the crop and, secondly, the timing of the stale seed bed (i.e. the period after the soil has been cultivated properly to stimulate emergence of weeds that are subsequently controlled by the definitive seed bed preparation). The effect of delaying crop sowing was analyzed using a historical data set from field experiments with 14 crops, e.g. broad bean, red beet, celeriac, green pea, evening primrose, scorzonera, silage maize, sugar beet. For sugar beet and maize, the experimental data were further analyzed using a model for crop growth. These analyses resulted into a table that gives for each crop the sowing date with on average the highest yield, and a yield reduction factor for every day the sowing is delayed. Effects of the length of the stale seedbed were analyzed using another historical data set on periodicity of emergence of a large number of different weed species. By combining results on both effects, a prototype Decision Support System was developed to advice the farmer in which crop and with which weed species a stale seedbed will be cost effective. In addition, innovations were developed to further increase the weed reduction, e.g. by covering a rotary harrow to prevent light induced weed germination while controlling the weeds. The results are discussed considering the response of farmers on the result