الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 212 |  |  |
| | | from | 212 | | |
Abstract
Three field experiments were carried out at the
Agricultural Research and Experiment Center of the
Faculty of Agri’culture at Moshtohor, Zagaz19· University
during 1981 andl982 seasons. The experiments aimed at
studying. the effect of inter- and intra-specific competition
on gro\-1thand yield of maize and soybean. The competitive
relationships as well as yield advantage gained from
int erc roppin g we re also conside red.
The, soil in which the experiments were undertaken
was clay with a pH value of 7.8 and an organic matter
content of 1.5%.
The first experiment:
Ef fect’o f int-ercrap pin!;’maize and soybean, on the growth
and yield of intercrop components:
The experiment airred to study the effect of intercropping
maize and soybean grown under 9 different intercropping
systems on the growth and yield of the intercrop
r: ”components., The- experi.ment included eleven treatments
which we re :
1. 10000 maize plants + 30000 soybean plants/fad.
(50% : 50% of pure stand density).
2. 10000 maize’ plants + 45000 soybean” plants/fad.
(50% : 75%. of pure stand density).
3. 10000 maize plants + 60000 soybean plants/fad.
(79% : 100% of pure stands density).
4. 15000 maize plants + 30000 soybean plants/fad.
(75% : 50% of pure stands density) •
5. 15000 maize plants + 45000 soybean plants/fad.
(79% : 75% of pure stands density)
- 173 .,
6. 15000 maize plants + 60000 soybean plants/fad.
(75%,+ 100% of pure stands den si tv ) •
7. 20000 maize plants + 30000 soybean plants/fad.
(100% .. 50% of pure st ands density)
8. 20000 maize plants + 45000 soybean plants/fad.
’(10~ : 75% of pure stands density).
9. 20000 maize plants + 60000 soybean’ plants/fad.
(10~ : 100% of pure stands density).
10. 20000· maize; plants/fad;., in pure, stand.
11. 60000 soybean plants/fad. in pure stands.
Intercropping was followed in alternate rows (2:2)
at all combinations io The expe rd.men t was laid. out in a
completely randomized block design with 5 replications.
The plot area was 21 m2• Maize cultivar was Pioneer 514,
a double cross, and soybean cultivar was Calland, a
medium maturity cultivar(Group. III) •
Soybean was planted on 23rd and 22nd May in 1981
and 1982 seasons, respectively.
Maize was planted on ~une 14 in both seasons (about
21 days after soybean planting). The normal cultural
pract ices· fa r both crops .,.,ere followed •
.Data on growth. characters, yield of- components and
seed and stra~ yield for int.rcrop components were
recorded.
ResuIt s co uld be summarized as follows:
A. Maize:
1. Intercropping maize and soybean at different densities reduced
slightly dry weight of maize plant organs. Increasing
the number of maize plants per unit area decreased
the dry weight proportionally to maize density.
Significant· difference wer~ rarely found 1n dry
weight/plant.
2 •. Growth characters of naize showed slight response to
intercropping. Stem diameter and percentage of
barren plants were si~}nificantly affected by intercropping.
The Lnc r-ee se in maize population intercropped
with soy.bean Ln cr-e ased the barren plant
percentage.
3-. Yield components of mClizewere not significantly
a ffected by in te rc rapping in spite 0 f some reduct ions
with increased intercr”opped maize population.
4. The grain yield of maj.ze ”adjusted” par unit area
increased significantLy by intercropping. The increase
ranged from 3 to 43% in the first season and from 33 to
55% in the second season over the grain yield of the
pure stand. Best resLlt was obtained for the treatments
including 75% : 50% and 100% : 50% maize and soybean
in the first and second season, respectively.
5. The straw,yield of maize increased significantly as a
result o.f intercropping and followed about the similar
trend of the grain yield.
B. Soybean:
6. Intercropping reduced the dry matter content of soybean
plant organs compared with solid planting. The greatest
reduction was brought about in the dry weight of
soybean pods.
7. Also growth characters and yield components of intercropped
soybean we re reduced as a result of intercropping.
The effect of intercropping on plarith.ight,
seed weight/plant, number of pods/plant and 100-seed
weight reached ~he level of significance.
8. Intercropping signlficantly_r~d~ced the seed yield of
soybean in both seasons. Relative seed yield ”adjusted”
per unit area ranged between 40 and 97% in the first
season and 61-100% in the second season, of the seed
yield of sale cropping.
9. The straw yield was not greatly affected by intercropping
as seed yield. Even, a great yield increase in
straw yield was recorded in the second season as a
result of intercropping. Such result indicates that
straw yield may follow an opposite trend of the seed
yield.
C. Competitive relationships and yield advantage:
10. Land equivalent ratio for intercropping maize and soybean
showed a yield advantage 1n 4. systems in the firs·t
season and in 8 systems (out of 9) in the second-season.
Best result was obtained for the intercropping association
75% maize + 100% 30ybean in the first season
(LER = 1.089) and 75% !lIaize+ 75% soybean in the second
season (LER = 1.199).
176
11. Relative crowding coefficient of maize exceeded 1
in all cases. but wal:;less than 1 for soybean. The
product of the coefficient obtained from intercropping
(K) exceeded 1 1n some soystems in the first season and
nearly in all systeml:iin the_second one. Maximum K
value was 1.49 in the first season and 2.52 in the
second one.
12. Aggressivity values showed that maize was the dominant
component in all casee whereas soybean was the dominated
component.
The Second Experiment:
Effect of intercropping .some soybean cultivars on growth
and yield of intercrop c:Emponents:
The experiment included 18 treatments which were the
combination of 6 daf f er-ein t cropping systems and 3 levels of
population densities.
Cropping systems were:
1. Calland cv. in sole planting. (included in maturity
froup III).
2. Clark cv. in sole planting (included in maturity group
III)•
3. Columbuscv. in sole planting (included 1n maturity
group III) •
4. Calland intercropped with Clark.
5. Calland intercropped with Columbus.
6. Clark intercropped with Columbus.
The three levels 0’= plant densities were:
(1) low (60000 plants/fad.), (2) medium (90000 plants/
fad.) and (3) high (120000 plants/fad.).
The experiment was laid out in a split plot design
with 5 replications. The main plots included the cropping
systems and subplots contained the levels of plant
densities. The suh plot area was 16.8 m2• The normal
cultural practicies of gr’;lwingsoybean were followed in
both seasons. Planting date wasl.23 and 22 May May in
both seasons.
Data on ~rowth characters, yield components, seed
and s~raw yield were recorde(.
Resul ts could be sumna rLze d as follows:
1. Intercropping showed some ~ffects on dry matter content
and growth characters IJf soybean cultivars where intercropping
reduced growth characters compared with sole
cropping. Columbus was more sensitive than Clark and
Calland where intercropping showed significant effect
on some growth characters.
2. Weight of 100 seeds of Calland was significantly
affected by intercropping where a reduction in this characters
were; recorded due to intercropping. Other yield
components were not affected byintercropping.
3. Intercropping significantly affected seed yield of
Calland (in one season) where a significant increase
was obtained. Wit h other cult ivars inte rcrapping
almost (insignificantli) increased seed yield.
Calland with Clark produced 33% yield increase in
the first season and 12% increase in the second one.
Calland with Columbus gave 11% yield increase in one
season but a 5% yield reduction in the other one.
Clark produc~d 6% more seed yield with Calland and
5% more yield with C31umbus in the first season as
against 8% increase and 6% reduction in the second
season.
Columbus gave 16 and 7% yield increase with Calland
in the first and second season, respectively, but 1%
and 13% yield reductions in combination with Clark in
the two successive seasons.
4. Plant density showed significant effect on some growth
characters of soybean cultivars particularly at later
stages of growth. Increasing the population density
reduced dry matter weight per plant and most of the
growth character studied with significant differences
in some cas es •
5. Yield components were also affected by population
density. Clark was more sensitive to density than
the other two cultivars where significant reductions
were observed in number of pods and weight of pods/
plant as well as in seed yield/plant.
6. Increasing the population density increased the seed
yield of the three cultivars with significant
differences 1n some cases. On the average of t he th ree
cultivars, increasing the density from 60000 to
90000 and 120000 plants/fad. increased seed yield
by 15 and 16% respectively in the first season,
being 11 and 5% in the second one.
7. Number of pods/plant and seed yield of Columbus
cultivar (in 1982 season) as well as seed yield
in 1981 season) and straw yield of Calland (in 1982
season) were significantly affected by interaction
between intercropping systems and plant density.
8. Intercropping soybean cult ivars produced a yield
advantage in both seasons. Best results were obtained
in LER values with intercropping Calland and Clark,
followed by Calland/Columbus then Clark/Columbus. The
LER values were 1.195, 1.143 and 1.014 in the first
season corresponding to 1.05~ 1.032 and 0.921,
respectively in the second season.
9. Intercropping soybean cultivars produced almost K
values exceeding 1 :Lndicating a yield advantage for
intercropping. Higher values we re for Calland/Clark
combinetion. Calland proved to be a good component in
intercropping.
10. Calland was a dom ananr component with Clark but a
dominated one with Columbus. Columbus was a dominant
component with Calland but a dominated with Clark.
Clark was the dominant with Columbus but the dominated
wit h Calland.
The Third Experiment:
Effect of intercrQ.Qping some maize cult iva rs·on growt h
and yield of intercrop components:
The experiment included 18 treatments which were the
combination of 6 different cropping systems and 3 levels
of population densities.
Cropping systems were:
1. Pioneer 514 (a double cross) cultivar in sole planting.
2. Giza 2 cultivar (a composite variety) in sole planting.
3. Ciba (a single cross) cultivar in sale planting.
4. Pioneer 514 intercropped with Giza 2.
5. Pioneer 514 intercropped with Cd ba ,
6. Giza 2 intercropped with Ciba.
The three levels of plant densities were:
(I) low (20000 plants/fad.). (2) medium (25000 plants/
fad.) and (3) high (30000 plants/fad.).
The experiment was laid out in a split plot deSign
with 5 replications. Tne main plots included the cropping
systems and the sub oLot s contained the levels of
plant densities. The subLplot area was 16.8 m2•
The normal cultural practices of growing maize
were followed in both S4:laSons. Planting date was 14 .June
in bot h seasons.
Data on growth cha rec re rs , yield components, grain
and straw yield were recorded. The competitive relationships
and yield adven t aq e of intercropping were estimated.
Results could be summarized as follows:
1. Intercropping showed significant effect on the dry
weight of plant orqena only in some combinations. Ciba/
Pioneer as well as Ciba/Giza 2 combinations reduced
the dry matter accumulation compared with sole
cropping of Ciba. Also -intercropping Giza 2 with
Pionee r dec rea sed the dry we ight 0 f leaves/plant of
Pioneer compared with sale cropping, but Giza 2 mixed
with Ciba increased leaves dry weight/plant.
2. Growth characters of maize were slightly affected by
intercropping. Stem cliameter of Ciba cultivar at
harvest, and number 01: ears/plant of Giza 2 were
significantly affectecl by intercropping.’ Intercropping
almost reduced these growth parameters.
3. Ear characters, namely, ear length, ear diameter,
number of grains/row, grain weight/ear, ear weight
and IOO-grain weight c f the three tested cultivars
were significantly affected by intercropping almost
in one season out of two. In all cases intercropping
reduced these characters compared with sale cropping.
4. Intercropping affected the grain and straw yields of
maize with different trend in both seasons. In most
cases. intercropping reduced grain yield per unit
area in the first season while almost increased it
in the second season.
S. Pioneer combined with Giba and Giza 2 produced
relatively 96 and 88% of the pure stand in the first
season. corresponding to 111 and 102%. respectively
in the second season. Giba combined with Pioneer
and Giza 2 produced 91 and 88% of the pure stand in
the first season and 35 and 107% respectively in
the second season.
Giza 2 in combination with Pioneer and Giba produced
relatively 99 and 98% of the pure stand yield in the
first season corresponding to 114 and 107% in the
second season.
6. Plant density i bad .no ma rked effect on growth characters
and dry matter of maizE! cuLtLva rs ;The dry weight of
different plant organs/plant were reduced with
increased population density. Such effect was rarely
significant •
7. Percentage of barren plants was increased with
increased population density particularly in Giza 2
and Giba cultivars.
8. Yield components in general and length and weight of
ear in particular were negatively affected by plant
density.
9. The grain yield df the cultivars was affected by
population density. Giza 2 responded significantly
to plant density where a significant increase was
recorded in both seasons.
In the first season increasing the density from 20
to 25 and 30 thousand plants/fad. increased the grain
yield by 15 and 23% ’for Pioneer, 37 and 37% for Ciba
and 15 and 23% for Giza 2.
In the second season, Pioneer grain yield showed
no response to population density, Giba grain-yield
recorded a slight decrease with increased density,
Giza 2 grain yield increased by 5 and 16% due to
increase in density.
10. Number of ears/plant ofCiba (in 1982), ear diameter
of Giza 2 (in 1982) and grain yield 0 f C iba cult ivar
(in 1982) were significantly affected by the interaction
between intercroppin~ system and plant density.
11. Land eqUivalent ratio due to intercropping showed
different results in both seasons.
In 1981 intercropping of the 3 cultivars in all
-combinations and under”the3 densities did not produce
any yield advantage.Pioneer/Giba, Pioneer/Giza 2
and Giba/Giza 2 produced LER values of 0.904, 0.957
and 0.931 respectively. The medium density was the
best one in that season.
In 1982, interc ropp ang increased the land usage
markedly where the mixed cropping of Pioneer/Giba,
Pioneer/Giza 2 and eiba/Giza 2 gave LER of 1.029,
1.071 and 1.089, respectively.
12. Relative crowding coefficient values were less than
1 in the first season indicating a disadvantage for
intercropping. In the second season, intercropping
proved promising whElre K values were 1.123 for
Pioneer/Giba, 1.344 for Pioneer/Giza 2 and 1.371 for
Gi.za 2/Giba. The mE:diumdensity was more effective
in t he second se asor- •
13. Aggressivity values were positive for Pioneer (in
Pioneer/Giba), for Ciza (in Pioneer/Giza 2, and Giba/
Giza 2) in both seaeons. Such result indicate a
great competitive abilities for Giza 2, fo1lo~ed by
Pioneer, then Giba.