Untersuchungen zur Unkrautunterdrückung in Rein- und Mischfruchtbeständen von Wintererbsen unterschiedlichen Wuchstyps

Abstract

Currently, normal-leafed long-vined and semi-leafless short-vined winter pea cultivars are available commercially. The weed infestation in pea crop stands is affected by both pea growth habit and cropping system. Intercrop compositions of normal-leafed or semi-leafless winter peas and cereals have to be improved in order to combine good weed suppression with high yield performance. Therefore, more knowledge on the weed suppressive ability of normal-leafed and semi-leafless winter pea-cereal intercrops and the underlying factors is needed. In 2009/10 and 2010/11, the normal-leafed winter pea cv. E.F.B. 33 and the semi-leafless cv. James were grown as sole crops and in an intercrop with triticale (40 germinable kernels winter peas + 150 germinable kernels triticale m 2 ) in field experiments in Northern Germany. Six intercrop compositions of each win ter pea cultivar (20, 40 or 60 germinable kernels winter peas + 150 or 75 germinable kernels triticale m 2 ) were examined in 2011/12 and compared to the respective winter pea sole crops. Normal-leafed winter peas had a better weed suppressive ability than semi-leafless winter peas. Intercropping was effective in reducing a weed infestation in semi-leafless pea crop stands, whereas the weed infestation in normal-leafed pea crop stands was comparable between cropping systems or significantly lower in the intercrop. Intercrops with a high triticale sowing density suppressed weeds to a higher extent than those with a low triticale sowing density. The underlying factor of a better weed suppression was a lower PAR transmission to the weed canopy level, whereas a crop-weed competition for nitrogen or water did not sufficiently explain differences in the weed suppressive ability between pea growth habits or cropping systems.