EFFECT OF NITROGEN, PHOSPHOROUS AND SULFUR LEVELS IN SOIL ON BRADYRHIZOBIUM AND MYCORRHIZA INTERACTION IN COWPEA PLANTS UNDER CALCAREOUS SOIL CONDITIONS

Abstract

SUMMARY The present •work was carried out to study the effect of nitrogen,

phosphorus and sulfur applications in soil on Bradyrhizobium and mycorrhiza interaction in cowpea plants (Vigna unguiculata (L.) walp.) under calcareous soil conditions.

A pot experiment was carried out for two months under greenhouse conditions at the Faculty of agriculture, Saba Basha, Alexandria University. The Pots were arranged statistically in a Completely Randomized Design as factorial experiment, using three replicates for each treatment. The treatments included four levels of Biofertilizers (uninoculated (control), and inoculation with mycorrhiza, Bradyrhizobium and their combination), three levels of nitrogen (0, 30 and 60 kg N fed-1 ), as ammonium nitrate, three levels of phosphorus ( 0, 30 and 60 kg P205 fed-1 , as rockphosphate and two levels of sulfur (0 and

600 Kg S fed-1

as elemental sulfur. Data were recorded for shoot and

roots fresh and dry weights and their heights, number and dry weight of pods and nodules, percentage of root infection by arbuscular mycorrhiza, shoot and root macronutrients and shoot micronutrients.