[Dynamics of weed number and the composition of their varieties in Latvia during last fifty years]
1999
Lapins, D. (Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Agriculture. Inst. Crop Sciences. Dept. of Soil Management)
On the ground of the scientific investigations at the Latvia Plant Protection Centre (1947-1981) and the Latvia University of Agriculture (1994-1998) the dynamics of grain crop weediness in Latvia has been analysed. It has been established that such weed species as Bromus secalinus L. and Agrostemma githago L. have almost disappear. The number of Galium aparine L. and Veronica sp. is increasing in crop agrocenosis. In the last 50 years the occurrence of Agropyron repens (L.) in crop sowings has increased. At the beginning of 1980-ies the level of grain crops weediness in some regions of Latvia (Kurzeme and Zemgale) was not lower than that of 1994-1998.
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