EFFECTS OF SOWING TECHNIQUE ON YIELD FORMATION OF VICIA-FABA AS AFFECTED BY POPULATION-DENSITY, SOWING DATE AND PLANT TYPE

Field experiments were carried out in which three different sowing tec hniques: sowing by hand, with a conventional seed drill and with a pre cision drill, were used to plant an indeterminate and a determinate cu ltivar of Vicia faba at two sowing dates and at three population densi ties in 1989 and 1990 in Southern Germany. Delayed sowing reduced fiel d emergence rates in both years. Hand sowing produced the poorest stan ds in some instances due to an insufficient sowing depth being achieve d. Only at late sowing dates did precision drilling give greater field emergence rates than conventional drilling. During the early stages o f growth, hand and precision sowing resulted in crops with the greates t light interception and dry matter production. However, these differe nces between sowing techniques decreased later on. Lodging was most se vere in conventionally drilled crops, particularly at high population density. Thus, when lodging occurred, dry matter and grain yields decr eased with increasing plant density in conventional sowings, although they tended to increase in hand-sown and precision-drilled crops. Over all, apart from this interaction, there was no significant effect of s owing technique on grain yield. Grain yields and dry matter production were generally higher in the indeterminate cultivar Herz Freya than i n the determinate cultivar Ticol, but there were no differential effec ts of sowing technique.