EVALUATION OF CROP WATER USE EFFICIENCY FOR SOME VARIETIES OF SUDANESE AND EGYPTIAN COWPEA AND ITS RELATION TO PRODUCTIVITY

Abstract

The current work was carried out during two seasons 2000 and 2001 in the Agricultural Experimental Station of the Desert Research Center at Maryut, Alexandria Governorate, Egypt. The study intends to evaluate the influence of soil moi sture deficit, irrigation water amounts and plant density population and their interaction on growth characters, y ield and yield components, actual evapotranspiration, water use efficiency, water economy, crop coefficient, stress coefficient and irrigation efficiency of Sudanese and Egyptian cowpea grown under ca lcareous soil conditions. Ex perimental treatments: The treatments include: Three soil moisture deficits from available soil water: (D1 = 30 % & D2 = 50 % and D3 = 70 %), three quantities of irrigation water calculated by using: (Q1 , Priestley & Taylor model, Q2, Penman - Monteith eq uation and Q3, Radiation method) and three plant density population treatments: (PO1 = I 00 % (low), P02 = 110 % (medium) and P03 = 120 % (high). Four replicates. The obtained results can be summarized as follows : A) Effect of soil moisture deficit: 1 - Highly significant effect and significant differences are found in number of pods per plant, number of seeds per pod, seeds weight per pod, seeds weight per pl ant, 1 000-seed weight, plant moisture content %, straw yield, seed yield , total fresh yield and total dry y ield, and significant differences on all growth characters, yield and yi eld components, water use efficiency and water economy of Sudanese and Egyptian cowpea during the two seasons, the common magnitude is in the order: 02 > 0 1 > OJ. 2- Highly significant effect and significant differences are observed in actual evapotranspiration (ETa), crop coefficient (Kc), stress coefficient (Ks) and i rrigation efficiency (Ea) of Sudanese and Egyptian cowpea during the two seasons. In brief, (ETa), (Kc), (Ks) and (Ea) decreased with increasing soil moisture deficit, the common magnitude is in the order: D 1 > 02 > OJ. of Sudanese and Egypti an cowpea during the two seasons.