الفهرس 
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Abstract
S~U-M-M-A-R-Y-&--C-0-N~CL-U-~-r~O-~-S--~
Three field experiments were conducted at the Research
and Experimental Station of the Faculty of Agriculture at
Moshtohor, Zagazig, U~iver8ity in the three successive growing
seasons of 1980, 1981 and 1982.
Soil texture of the eXFerimental plots was clay.
This investigation was carried out to study the effect
of some soil tillage practices on growth ~~d yield of cotton.
The aim of this study was to select the optimum tillage
practices producing improved soil properties and sequently
higher yield is resulted.
The experiment included 10 treatments which were the
combination of two subsoiling treatments and five different
tillage methods.
1. Without subsoiling
2. With subsolling
1. One way ploughing with. Baladi (15 em depth).
2. One way chiselling (20 em depth).
J. One way chiselling followed by one way harrowing
(20 cm depth) •
• L. ..•
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4. Two ways cniselling (20 cp depth).
5. Two ways chiselling followed by two ways harrowing
(20 em dep t h ) •
The experiments were designed in a split ~lot design.
The obtained results could oe cWfu~arized as follOws:
1. One way ploughing either with Baladi or chisel plough
had no effect on bulk density and porosity on the all
hand.
2. One way chiselling followed by one way harrowing
increased soil porosity decreased bulk density.
). Dry weight of roots was significantly affected by
frequency of ploughing and harrowing.
4. The effect of frequency of ploughing and harrowing
were significant on the dry weight of leaves/pl~~t.
5. There was a significant effect of frequency of
ploughing and harrowing on the dry weight of stems.
6. Plant height of cotton was significantly affected by
two ways chiselling followed by two ways harrowing.
7. Two ways chiselling followed by two ways harrowing
increased number of open bolls/plant.
8. There was a significant effect of the frequency of
ploughing and harrowing on the seed cotton yield in
the three studied seasons.
9. SUbsoiling operation increases soil porosity and
decreases soil bulk density.
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10. The effect of 6ubsoiling operations were signific~nt
on the dry weight of roots. Using subsoiling produced
the highest dry weight of roots/plaut.
11. Dry weight of leaves was significantly affected by
s~b6oiling operations. Dry weight of leaves increased
by using sUbsoiling.
12. The effect of subsoiling treat~ent were signific~~t
on the dry weight of ste~8/plant. Dry weight of stems
significantly increased by using suosoiling.
1). Plant height of cotton was significantly affected by
subsoiling operation. The heighest plants were obtained
by using subsoiling.
14. SUbsoiling operation increases the nuober of open
bolls/plant.
15. Seed cotton yield was significantly affected by using
su~soiling. Subsoiling operation increases seed cotton
yield by 1) % to other treatments.
16. There was no significant effect of the interaction
between subsoillng and seedbed preparation on soil
bulk density, porosity and salinity of soil.
17. The highest increase in dry weight of different organs
of cotton plant was obtained by two ways chiselling
followed by two ways harrowing witn subsoiling.
18. Number of open bolls/plant was not si6nlficantly
affected by the interaction between 6ubsolling and
seedbed preparation.
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19. Seed cotton yield was significantly affected by the
interaction. The highest seed cotton yield was
obtained by two ways chiselling followed by two ways
harrowing with subsoiling.
In conculosion frequency of ploughing and using
8ubsoiling increase the yield of cotton, but there
is a little benefit in using two ways harrowing
compared with the cost of frequency of harrowing.