STUDIES ON PHOSPHORUS IN SOME SOILS OF EGYPT

Abstract

Three pot experiments were conducted to study the effect of placement methods of P fertilizer, and pplication of organic acids, ammonium thiosulfate and organic fertilizers on the efficiency use of P fertilizers in some soils of Egypt by faba bean plants. The results were as the followings:

Experiment (1 ):

• Shoot dry weight increased as the level of P applied was increased and the addition of 30 kg PO/fed. proved the superiority. Phosphorus application at the rate of 15 and 30 kg PO,/fed. increased the dry weight by 24 and 36%, respectively than control in alluvial soil. On the other hand, these increases were 32 and 42% in calcareous soil. • Dry weight was higher for plants grown in alluvial soil than those grown in calcareous one . t • As regards the placement methods, the increase in shoot dry matter t was significant for the band and hole methods compared to the surface P placement method. The relative increase in dry weight compared to surface application were 9 and 15%, respectively, in alluvial soil.

• Under the different P placement methods, the variations in N concentration were not significantly affected by the P rates in both soils.

• The application of P fertilizer at rates of 15 and 30 kg PO, /fed increased the N content by 24 and 37%, respectively, over control in alluvial soil. On the other hand, these increases were 28 and 3 8% in calcareous soil.

• Regarding the effect of P placement methods, the data showed that shoot nitrogen content in the surface placement method was generally lower than for the band and hole P placements. The