POTASSIUM FERTILIZATION FOR SOME INTERCROPPING PATTERNS IN EGYPTIAN NORTHERN DELTA SOILS

Two factorial field expeeriments were conducted during 1991/ 1992 season, the first on sugar beet/faba bean and the second on maize/soybean intercropping patterns to evaluate the relative efficien­cies and economic optimum rates of k- sulfate fertilizer. The soil experimental sites were clayey in texture and the aver­age values of chemical characteristics were as follows : Ec_o -2.20 dSm^-1, pH -8.26, O.M. -1.36% and the available N-, P- and k- were 51, 9 and 347 mg.kg ¹, respectively. The results showed that potassium fertilization as k- sulfate was beneficial for sugar beet, faba bean, maize and soybean whether grown in monocropped or intercropped patterns. The relative k- fertilizer effi­ciencies were reduced in intercropped patterns compared to monocrop­ping systems. The economic optimum k- fertilizer rates inceased in inter-cropped patterns relative to monocropped patterns. The values of (E.O. k- rate)/(E.O. crop yield) ratio were lower under monocropped patterns relative to intercropped ones.