ENRICHMENT OF PHOSPHORUS FOR COWPEA (Vigna unguiculata L. Walp.) UNDER CALCAREOUS SOIL CONDITIONS AT EL-ARISH REGION

Abstract

This study was carried out during 2012 and 2013 summer seasons at The Experimental Farm of Fac. Environ. Agric. Sci., El-Arish, North Sinai, Egypt, to study the effect of lowering the recommended phosphorus dose with foliar phosphorus addition on growth and productivity of cowpea (Vigna unguiculata L. Walp.) plants. This experiment included 7 treatments which were: The control which was the recommended rate of phosphorus fertilizer as soil addition (40kg P2O5/fed.) (T1), 100% of the recommended dose + spraying with phosphorus once weekly at rate of 2% of super phosphate (T2), 100% of the recommended dose + foliar spray twice weekly (T3), 75% of the recommended dose + foliar spray once weekly (T4), 75% of the recommended dose + foliar spray twice weekly (T5), 50% of the recommended dose + foliar spray once weekly (T6) and 50% of the recommended dose + foliar spray twice weekly (T7). Results show that application of T6 caused maximum plant height, stem length and total dry weight and differed significantly with other treatments, while T5 gave rise to maximum number of branches and leaves area per plant. Most of growth parameters were enhanced with the decrease of phosphorus soil addition and spraying with foliar phosphorus. Treatments have a significant effect on green pods yield, seeds yield, number of seeds per pod, protein %, protein yield and pod weight. Phosphorus treatments have a significant effect on weight loss % at room and cold storage conditions. Color changes as b* and c* at the case of storage at room temperature (28.5 ±5°C) were more acute after 5 days of storage than cold storage (14±1°C) conditions.