الفهرس 
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Abstract
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V. SUMMARY
Two field experiments were conducted during 19B3 and
1984 seasons at the Agricultural Research and Experiment
Center of the Faculty of Agriculture at Moshtohor, Zagazig
university, Kalubia Governorate, Egypt.
The aims of this study were to determine the effect
of weed control, nitrogen fertilizer levels, plant density
and their interactions on growth, yield, yield components
of Giza 2 maize cultivar and associated weeds.
Each experiment included 36 treatments which were
arranged at random in a split-split plot design with four
replications where plant densities( 20,000, 24~OOO and 30,000
plants/fad.) were distributed in the main plots, nitrogen
levels (45, 90 and 135 Kg.fad.) were assigned to sub-plots
and the SUb-sub plots were alloted to weed control treatments
( unweeded, hand-hoed, chemically treated maize by Gesaprim
and Laddok).
The most important results could be summarized as
follows:
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A- Effect of plant density:
1. Densities differed significantly in ear length, number
of kernels/row, ear weight, weight of grains/ear in
1983, leaf area of topmost ear and stand plants at
harvest in 1984 and stem diameter in both seasons.
Both the thin and the medium plant densities were higher
in those characters than the dense planting, while the
differences between thin and medium densities were
almost insignificant.,
2. Plant population densities exhibited insignificant
differences in number of days to 50% tasseling and
silking in 1984 season and plant height, number of
green leaves/plant, ear diameter, number of rows/err,
shelling percentage, IOO-grain weight, hectoliter
weight, grain and straw yields ( ton/fad.) and N,P,
K % of maize grains in both seasons.
3. Densities had no significant effect on dry weight of
most weed groups in both smaples and seasons except
on narrow:”leaved group at 40-days from planting of
the first season only.
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B- Effect of nitrogen fertilizer levels:
1. Nitrogen levels affected significantly plant height,
stem diameter, number of days to 50% silking in 1984.
Nitrogen level of 90 Kg/fad~ surpassed the two other
levels in its effect on plant height and stem diameter
but the higher nitrogen level (135. Kg/fad.) was superior
in promoting early silking.
Also, it produced significantly more green leaves/
plant.
The differences in leaf area of topmost ear were insignificant
between levels in both seasons, likewise the
number of days to 50% tasseling in 1984 season~
2. Both ear length in the two seasons and shelling precentage
in the first season were significantly affected
by nitrogen levels. Nitrogen levels had significant
effect on ear diameter, number of kernels/row, ear
weight, weight of grains/ear, lOO~grain weight and
grain yield (ton/fad.) in 1984 season.Increasing
nitrogen level from 45 to 90 and 135 Kg/fad. increased
the grain yield by 34% and 37%, respectively.
Stand at harvest, number of rows/ear, hectoliter
weigth and straw yield(ton/fad.) were insignificantly
affected by various nitrogen levels in both seasons . .’
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3. There was no significant effect of nitrogen levels
on N, P and K% of maize grain in both seasons of
study.
4. Nitrogen levels had no significant effect on dry
weight of most weed groups in both samples (at 40
and 60 days from planting ) as well as seasons except
on narrow-levaved group at the first sampling date
of the first season only.
c. Effect of weed control treatments:
1. Weed control treatments aftected significantly plant
height, stem diameter, number of green leaves/plant
and leaf area of tompost ear in both seasons and number
of days to 50% tasseling and silking in 1984 seas cnj-.
All weed control treatments significantly surpassed
unweeded treatment in improving maize growth measurements,
meanwhile hand hoeing and Gesaprim had the
best effect on those characters.
2. Stand maize plants at harvest, ear length, ear diameter,
number of rows/ear, number of Kernels/row, ear weight,
weight of grains/ear, grain-and straw-yield (ton/fam.)
were significantly affected by weed control treatments
in both seasons.
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Both chemical and mechanical weed control treatments
improved most yield characteristics of maize.
Grain yield of treated· maize was increased by 21 ;
105% for hand hoeing, 25; 96% for Gesaprim and 20: 77%
for Laddok as compared with unweeded maize in 1983 and
1984 seasons, respectively.
3. N,P and K% of maize grain were insignificantly affected
by weed control treatments in both seasons.
4. All weed control treatments exhibited significant effect on
dry weight of broad -,narrow-leaved weeds and their
total in both samples and seasons. It was clear that
hand hoeing was more efiective than Gesaprim on all
weed characters in both seasons. Laddok proved to
be very effective in controlling broad-leaved weeds.
Hand hoeing controlled 76: 65% and 81; 74% of total
weeds at 40 and 60 days from planting in 1983 and 1984
sesons, respectively , whereas Gesaprim application reduced
the total weeds by 54, 41% and 47, 39% in the two seasons.
respectively.
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On the other hand l.abddok killed 71,. 60% and 85 ••88%
of broad-leaved weeds of respective sampling dates and
seasons.
D- Interactions effect:
1. The effect of the interaction betweeB plant density
and N levels had a significant effect on P% of maize
grains in 1983 season, Other characters weIEnot
significantly affected by this interaction in both
seasons. The highest P% (0.163%) in maize grain was
produced by the medium N level (90 Kg/fad.) and the
medium density (24,000 plants/fa~.) while the highest
density (30,000 plants/fad.) supplied by the same N~
level produced the lowest P% (0.127%) of maize grain.
2. Only plant height in 1984 was significantly affected
by the interaction of N. levels with weed control
treatments. The tallest maize plants ~. produced
under the fertilization by 90 or 135 Kg N/fad. and
weedy treated with hoeing or Gesaprim , while the
lowest N level resulted the ~hortest plants in unweeded
maize plots.
3. The second order interaction of plant density, Nlevels
and weed control treatments affected significantly
ear weight of maize in 1983 season and dry weight of
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narrow-leaved weeds at 60 days from planting in 1984
season.
The highest value of ear weight(275.8 g) was produced
by maize plants grown by 20,000 plants/fad. s~pplied with
135 Kg N/fad. and treated by Gesaprirn, whereas unweeded
maize supplied with the lowest N level of 45 Kg/fad and
grown by medium density of” 24,000 plants/fad. produced the
lowest value of ear weight (196.9 g).
The lowest dry weight of narrow-leaved weeds(1.Og/m2)
was recorded by hand hoei~g treatment .fertilized with 13SKg
N and growing under 20,000 plants/fad. While the greatest
infestation of this weed group (12,9 g/m 2) was recorded in
20:000 plants/fad. and supplied with the lowest N level of
maize plots treated by Laddok and grown under a density of
45 Kg/fad.
4. Plant population density and weed control treatments
interaction had no significant effect on all studied
characters of maize and weeds in both seasons.