Effect of the variation of K+/(Ca2++Mg2+) ratios on strawberry (Fragaria annanas) growth cultivated on soilless crop system

Abstract

The study was conducted on soilless crop system. It has evaluated the effect of different K+/ (Ca2++Mg2+) ratios (Rp): 0.28, 0.5, 0.83, 1.14 and 1.42 on the growth characteristic of strawberry (Fragaria ananassa). The low Rp under 0.28 and the highest one 1.42 decreased significantly the height plant, leaf length, leaf width, petiole length, crown diameter, fresh and dry weight. The variation of Rp on the dry and fresh weight was correlated with R2 = 0.26 and 0.45 respectively. The same ratios decreased the main macro nu-trients K+, Ca2+ and Mg2+and the micronutrients Fe, Mn, Cu and Zn absorp-tion. The response of the Rp variation on the K concentration in the sap of the petiole and on that of the tissues were correlated with R2 = 0.81 and 0.97 respectively. The electrical conductivity (EC) varied from 1.8 to 2 dS.m-1 in all Rp. Its response to the variation of Rp was correlated (R2= 0.42) . The pH decreases with increasing Rp. It ranged between 6.8 to 7for all treat-ments. Its response to the variation of Rp was slightly correlated (R2=0.082).