الفهرس 
INTRODUCTION
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Abstract
The present study aimes to investigate the effect of Cd and Ni heavy metals on the growth, yield and nutrient composition of wheat and beans grown in a greenhouse experiments using sandy clay loam soil.
Four pot experiments were set up in greenhouse, each experiment includes 7 treatments. The replicates were four and set up in a complete randomized design.
Cadmium and Nickel were added at seven rates as follows:-
a - Cadmi urn rates:-
0.0, 5.0, 10, 20, 40, 80 and 160 ppm
b - Nickel rates:-
0.0, 2.5, 5, 10, 20, 40, and 80 ppm.
The results were as follow:
1- Effect of Nickel on wheat
1 - Foliage colour of plants growing on soil receiving rates up to 20 ppm was similar to the control. After 8 weeks of planting chlorosis was observed in plants grown in soil treated with 80 ppm.
2 - Low rates of Ni, from 2.5 to 40 ppm, increase the dry weight, straw and grain yield of wheat, but
higher rates of Ni, above 40 ppm caus~d a signific-
ant reduction.
3 - It has been found that Nickel became toxic to plants
when its concentration in the plants was greater
than 60.5 ppm as indicated by reduced plant dry
weight and visual toxic symptoms.
4 - The lower rates of Nickel (2.5 to 40 ppm) increase the uptake of Mn and Cu by plant
2- Effect of Nickel on beans
1 - When the concentration of Nickel in soil was 80 ppm,
foliage colour of beans had the same colour as the
bean plants grown in the control treatment.
2 - Lower concentrations of Nickel increased straw and
grain yield of beans, but higher reduced them.
3 - Nickel became toxic to bean plants when its concent-
ration in plant was greater than 57 ppm.
4 - The lower concentrations of Nickel in the soil;
(2.5 and 5 ppm) increase Zn and Cu uptake by plant.
5 - Higher rates of added Ni reduce grain and straw uptake of Fe, Mn, Zn and Cu when compared with the
control.
1 - 5 and 10 ppm level of Cd encourage wheat growth.
However, light chlorosis was observed in plants grown on soils recieved caamium levels of 160 ppm or above.
2 - Increasing Cd levels from 40 to 160 ppm redu-
ced grain yield of wheat by about 4 to 14% respec¬tively. Higher concentrations than 160 ppm reduced wheat straw yield as compared with the control.
3 - Cadmium became toxic to the plants when the concent¬ration in wheat plants was greater than 15.7 ppm as indicated by a reduction in plant dry weight.
4 - The lower levels of Cd increase plant uptake of Zn and Cu.
4- Effect of Cadmium on beans
1 - The foliage colour of plants growing on soil treated with Cadmium did not change.
2 - The lower concentrations of Cadmium in soil (5 and 10 ppm) increased the straw yield of beans.
3 - The reduction in straw yield of beans plants grown on soil with a levels of Cd from 20 to 160, ppm was 2 to 20% respectively of the control.
4 - It has been found that Cadmium become toxic when its concentration in the plant was higher than 7.95 ppm, though straw yield decreases.
5 - The lower concentration of Cd (5 and 10 ppm) incre¬ase plant uptake of Mn, Zn and Cu.
6 - Different rates of added Cd to soil caused a signi¬ficant reduction in grain yield of beans.
Extractable Cd and Ni after wheat and beans harves¬ting were significantly increased as compared with the control. The difference in the extracted (Fe, Zn, Mn
and Cu from different Cd and Ni) between treatments were significant as compared with the control.