Abstract The weed flora of the reclaimed desert lands in
the eastern and western stretches of Qena Governorate
along the Nile Valley was investigated. This study
attempted to identify the vegetation groups (communities)
prevailing in common winter and summer crops, to
recognise the crop–weed relationships, and to assess the
role of different soil factors on the distribution and composition
of the weed flora in each season. Three major
crops were selected: alfa–alfa (winter and summer seasons),
wheat (winter season) and millet (summer season).
Altogether, 146 studied fields (stands) were monitored, and
distributed as follows: 49 in the wheat fields, 38 in alfa–
alfa (summer season), 24 in alfa–alfa (winter season), and
35 in millet fields. Frequency (f %) of weed species within
the different crop farmlands was used as measure of ecological
success. The total number of species varied among
the studied crops: the highest was 131 species in alfa–alfa
(the perennial crop), followed by 111 species in wheat (the
winter crop), and the lowest (29 species) was in millet (the
summer crop). The relationships between the recorded
species and crops were discussed. TWINSPAN as a classification
method and DCA as an ordination methods were
used to assess differences in floristic composition in different
seasons. The resulted TWINSPAN vegetation groups
from winter and summer seasons were clearly separated
along the first 2 axes of DCA. Canonical correspondence
analysis was used to evaluate the relationships between the
examined soil factors and the floristic presence/absence
data sets in each season.