Journal of Agricultural Science, Cambridge (1994), 122, 255-264. © 1994 Cambridge University Press 255 Effects of sowing technique on yield formation of Vicia faba as affected by population density, sowing date and plant type H. STUTZEL, W. AUFHAMMER AND A. LOBER Institut fiir Pflanzenbau und Griinland {340), Universitat Hohenheim, D-7000 Stuttgart 70, Germany {Revised MS received 18 June 1993) SUMMARY Field experiments were carried out in which three different sowing techniques: sowing by hand, with a conventional seed drill and with a precision drill, were used to plant an indeterminate and a determinate cultivar of Vicia faba at two sowing dates and at three population densities in 1989 and 1990 in Southern Germany. Delayed sowing reduced field emergence rates in both years. Hand sowing produced the poorest stands in some instances due to an insufficient sowing depth being achieved. Only at late sowing dates did precision drilling give greater field emergence rates than conventional drilling. During the early stages of growth, hand and precision sowing resulted in crops with the greatest light interception and dry matter production. However, these differences between sowing techniques decreased later on. Lodging was most severe in conventionally drilled crops, particularly at high population density. Thus, when lodging occurred, dry matter and grain yields decreased with increasing plant density in conventional sowings, although they tended to increase in hand-sown and precision-drilled crops. Overall, apart from this interaction, there was no significant effect of sowing technique on grain yield. Grain yields and dry matter production were generally higher in the indeterminate cultivar Herz Freya than in the determinate cultivar Ticol, but there were no differential effects of sowing technique. INTRODUCTION intercept more light energy during the early stages of growth, although they did not differ from conven- ln order to keep faba bean {Viciafaba L.) production tionally drilled crops with respect to total and seed competitive, relative to other crops, inexpensive ways DM produced during the whole growing season of improving yield and increasing yield stability (Heath & Hebblethwaite 1987). Thus, it appears that should be investigated. Optimization of sowing pea crops have a substantial ability to compensate for technique can be relatively inexpensive but its benefits suboptimal initial plant number and distribution will presumably depend on the prevailing natural and during later growth. The influence of plant dis- agronomic conditions. tribution as modified by row width on total and seed Planting depth and horizontal seed distribution DM of faba bean appears to depend on cultivars and have a considerable effect on field emergence. In growing conditions (Oliphant 1973). In Canadian comparison to conventional seed drilling, precision experiments, halving the row width from 30 to 15 cm sowing of faba bean has been found to produce higher resulted in yield increases between 0-5 and l-9t/ha field emergence rates due to more regular seed spacings (Seitzer & Evans 1973). British investigations showed within the row (Kondra 1975; Heege 1989) and positive effects of narrow rows, particularly in short greater sowing depth (Heege et al. 1985). In contrast, cultivars (McEwen & Yeoman 1989). The variation in Konig (1980) found no difference between the effects row width between 11-9 and 47-6 cm had no significant of a conventional seed drill and a precision sowing influence on the short, but branching, cultivars Alfred device, but observed a reduction in field emergence and Ticol (Pilbeam et al. 1989). Cultivar differences in with increasing row width. the reaction to changing row widths (Kondra 1975) Light interception and dry matter (DM) production can be explained by the fact that tall or branching rates can be expected to increase with increasing plant genotypes are, particularly at greater row widths, number and homogeneity of a crop stand. Accord- more capable of complete light interception than ingly, precision-sown pea crops were found to short or single-stem genotypes.