الفهرس 
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Abstract
A field experiment was carried out in a sandy soil at El Ismailia experimental farm of Agric. Res. Station. The farm is located at 30º35 ̀41.9 ̏ N latitude and 32 º 16 ̀45.8 ̏ E longitudes. Three-factor computer model was implemented to study the combination effect of X1 (polyacrilamid + bentonite), X2 (biocompost) and X3 (gypsum + sulphur + rock phosphate) on soil properties and plant growth. Wheat (Triticum aestivum L) plant (Giza 168) was chosen as an indicator crop to study the effect of different combination of soil amendments on some physical characteristics of sandy soil, growth characters and nutrient contents and uptake of wheat crop. Results showed an improvement in soil physical properties and increases in all wheat growth characters as a result of different combination of the used soil amendments compared to the control treatment.
However, total porosity (TP) show a highly significant correlation coefficient (r = 0.99, 0.91, 0.81 and 0.96) with saturation percentage (SP), soil field capacity (FC), wilting point (WP) and available water (AW), respectively. The maximum values of TP was obtained with the combination ratio of 16.6%, 66.6% and 16.6% for X1 (polyacrilamid + bentonite), X2 (biocompost) and X3 (gypsum + sulphur + rock phosphate), respectively. Also, wheat growth characters include grains, straw, biological yield, weight of 1000 grain and some morphological yield (plant height & spike length) showed an increase by the application of soil amendments with highly correlation coefficients (r = 0.99, 0.99, 0.98, 0.94 and 0.85) with grains yield, respectively. On the other hand, nitrogen, phosphorus and potassium status in soil and plant were significantly affected by all combination of X1 (polyacrilamid + bentonite), X2 (biocompost) and X3 (gypsum + sulphur + rock phosphate) soil amendments application. Finally, data indicated that it is important to apply biocompost with other amendments to increase available N, P, and K in sandy soil which was reflected on their content and uptake by wheat grains.