الفهرس 
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Abstract
Two pot experiments were carried out in two growing seasons (May 1991, 1992) to study the effect of adding soil amendments polyacrylamide (PA), sewage sludge (SS) and poultry manure (PM) at three rates (0.1, 0.25, 0.5 % for PA and 1.0, 2.0, 3.0% for SS and PM) to sandy and clay soils on some biochemical constituents of soybean
plant.
The investigation was carried out in green house’ at SWERI, ARC, in complete randomized design.
The most important results are summarized that soil amendments improved soil moisture retention in the following order PA
> PM > SS. However PM had a marked effect on reducing a quickly
drainable pores and increased available moisture capacity than those of
PA and SS.
The results showed that, PA had no effect on soil pH or EC. On the other hand, SS and PM decreased pH values was more effective more than SS. In contrary, SS and PM increased EC values. Also, soil organic matter content increased due to SS and PM application and PM was the superior but PA was less effective on increase soil organic matter content.
The nutrient availability (N, P, K) increased due to amendments application in the following order PM > SS> PA.
With regard to response of plant nutritional status to amendments treatments, generally PA. SS and PM addition were led to significant increase the plant nitrogen content in the early stages but the increase was Insignificant in the seeds (stage Ill) in the two kinds of
• used soils. Also phosphorus percentage of seeds increased due to amendments application except in PA treatment the increase was insignificant. Potassium percentage increased by PA addition but this increase was significant when the third rate was applied. SS treatments Jed to increase K % at stage II and stage Ill however PM resulted in increase K % at stage I and stage II.
The dry matter yield of soybean increased due to soil amendments application so the second and third rate of PM and PA were superior to increased dry matter yield. On the other hand SS treatments in clay soil led to decrease the dry matter yield.
Total protein content increased due to PA application specially at the third rate while the effect of second rate of SS and the second and third rates of PM led to increase protein percent than the others rates. The amino acids were analyzed using GC apparatus and the obtained data showed changing in the individual amino acids percentage in some cases.
Total lipids percentage of soybean seed grown in sandy soil had no significant response due to PA, SS and PM treatment as well as the fatty acids composition of oil. On the other hand, total saturated fatty acids tend to slight decrease due to amendments application in contrary, total unsaturated fatty acid showed slight increase.
There was no significant effect on reducing sugars, total soluble sugars and total carbohydrates due to PA treatments but the third rate of SS Jed to increase the total carbohydrate percent and the second rate Jed to decrease the total soluble sugars; However PM treatment resulted in decrease the reducing sugars at the first rate and the total soluble sugars at the third rate.