الفهرس 
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Abstract
Summary
Many heavy metals can find their way to the soil in high rates and
so they act as permanent sources of heavy metals pollution forall the types
of life either through the soil or on the earth plant itself.
This study aims to investigate the effects due to some of those
heavy elements that may act as soil pollutants ( Zn, Co and Cr ) , applied
at high rates on soil and plant.
The effects were considered with respect to cotton, carrot, sorghum,
wheat, clover and bean, also heavy metals movement and transformations
in soils were evaluated through theses experiments as follows:
Exp ( I ): Germination experiment:
This experiment was conducted using a sand culture technique
where the germinated seeds were to increasing applications of tested
heavy metals, the obtained results showed the following:
Zinc applications did not adversely affected the germination
percentage of bean seeds even at its highest rate (500 mg.kg-l) , while
the germination of clover, cotton and carrot was reduced with Zn rates
as low as 50 mg.kg-1. Germination of both sorghum and wheat seeds
was adversely affected with Zn applications at a rate of 100 mg.kg !.
Cobalt applications adversely affected seeds germination in the
order
I) Bean 20 mg.kg l Zn or more
III) Clover, cotton and carrot 1O’mg.kg! Zn or more
Chromium application did not adversely affect bean germination
even at its highest rate of applications. On the other hand the germination
percentage of all the anther tested seeds (sorghum, wheat, clover, cotton
and carrot) was diminished even with the lowest rate of Cr application
(lO mg.kg-I )
Experiment (II) : Plant growth and utilization of
elements:
This experiment was conducted under green house conditions, using
soils representing the alluvial clay, calcareous and sandy soils. Growth,
dry matter yield and concentration ( content) as well as total uptake of Zn,
Co and Cr by sorghum and carrot plants grown on the above mentioned
soils supplied with increasing rates of these elements were evaluated . The
obtained results showed the following:
Dry matter yield:
** Dry matter yield of sorghum gained from the tested three soils
respond to Zinc application in quiet different trends as follows:
* In alluvial clayey soil, sorghum plants slightly and progressively
responded to Zn applications up to the highest rate (400 mg. kg-1 ) . Where
the maximum increase (28 %) occurred.
* With respect to the calcareous soil, though the maximum increase
(18 %) was yielded with Zn application at the highest rate, an increase of
(17%) occurred with the application rate of 200 mg. Zn.kg-1 soil only. *
* The sandy soil showed a maximum response (140/0) corresponding
to rate of Zn application ( 100 mg.kgr l)
** Dry matter yield of carrot, positively responded to Zn application up
to limits that different from one soil to another as follows:
I) Alluvial clay soil up to 100 mg Zn.kg-I
II) Calcareous soil up to 150 mg Zn .kg-I
III) Sandy soil up to the highest rate (400 mg. kg-I )
Further increases in the rate of application, adversely affected the dry
matter yield of carrot in both alluvial and calcareous soils.
• • Cobalt application enhanced dry matter yield of sorghum and carrot
grown on the tested soils, where the positive effect lasted till a certain
level of application according to the following pattern:
Sorghum
Alluvial clay soil : up to 50 mg.kg-l
Calcareous and sandy soil : up to 30 mg.kg-I
Carrot
up to 30 mg. kg-I
up to 40 mg.kg-I
With higher rates of application, the dry matter yield was adversely
affected.
4 •• Except to Chromium application at the lowest rate (5 mg.kg-1) to
carrot grown on the tested soils, all the treatments of Cr with both plants
adversely affected the dry matter yield of plants . This true with respect to
the tested three soils.
Elemental content:
Concerning the elemental concentration (content) in plants, the
values of Zn, Co and Cr progressively increased in both sorghum and
carrot grown on the tested soils with increasing the rate of elemental
application. However, there was only one exception with carrot grown on
calcareous soil as affected by Co application where its content was
maximized with application rate of 40 mg.kg-l Co. Further rates reduced
the Co concentration in carrot.
Total Uptake:
As for total uptake of the tested elements, , results showed that Zn
and Cr applications at any rate and to any soil ( except the highest Cr rate
i.e. 25 mg.kg”! in case of the sandy soil) progressively increased the total
uptake of both elements either in sorghum or in carrot, (particularly in
sorghum shoots in case of Zn) .
Cobalt application up to certain level increased the total uptake of
the element. The higher rates of application yielded an inverse affect. The
maximum application rates 100 mg.kg” 1 that positively affected the total
Co uptake could be shown as follows:
Soil : Sandy calcareous
Sorghum 100 40
4:arrot 100 30
Alluvial clay
50 mg.kg!
100 mg.kg-I
Translocation in plant:
Concerning the rate of elements translocation to upper plant parts
(%) results showed more than one trend as follows:
Zinc applications to the tested soils enhanced the translocation
rate ?f z:n . This was true in case of carrot up to the highest rate of
application and up to the third one (l SO mg.kg! ) in case of sorghum .
Chromium application at the lowest rate reduced the rate of Cr
translocation i.e. the element tended to accumulated in plant roots. This
was for both sorghum and carrot grown on all the tested soils.
With respect to Cobalt application, the results differed according to
the type of soil and type of plant with an almost constant rate of Co
translocation in case of the alluvial clay soil.
Fe in plant as affected by elemental applications:
Results of total Fe uptake as affected by the involved treatments
showed the following trends:
Zinc as well as Cobalt application at relatively lower rates tended
to increase Fe uptake but with higher application rate of both elements, an
inverse trend was obvious.
However, there was one exception for carrot growth the alluvial soil
where Fe uptake was always reduced with Co application at any rate.
Chromium application drastically reduced Fe uptake in the alluvial
clay soil and to a lower extent in the sandy soil but did not affect it in case
of the calcareous soil.
P in plant as affected by elemental applications:
Phosphate uptake responded to elemental applications in the following
trend:
Zinc applications up to 1SOmg.kg-I tented to increase P uptake,
but with higher rates of Zn application, the reverse was true.
Cobalt application adversely affected P uptake in sorghum while
Co induced P uptake of carrot when it was applied a relatively low rates (
up to 30 or 40 mg.kg-I )
Chromium application negatively affected P uptake under the
different treatments tested.