PHOTOSYNTHETIC ACTIVITY IN RELATION TO FODDER BEET PRODUCTIVITY WITH DIFFERENT PLANTING METHODS AND DENSITIES UNDER SANDY SOIL CONDITIONS

Fodder beet could be cultivated under varied environmental conditions; their yield and stomatal conductance differ according to planting methods and densities. So, two planting methods (transplanting, T. and direct seeds, Ds.) under six planting densities (33.6, 28.0, 24.0, 21.0, 18.6, 16.8 thousand plants fad^-1) were investigated on fodder beet (Beta vulgaris L.) at sandy soil (70% sand) of the Experimental Farm of the Faculty of Environmental Agricultural Sciences, Arish Univ., Egypt, during 2012/2013 and 2013/2014 seasons. The experimental design was randomized complete block (RCBD) in a split plot design with three replications. The main plots were chosen for planting methods, while, the sub-plots were devoted for planting densities. Drip irrigation system was used with saline ground water (3500 ppm) pumped from a local well. Results showed that stomatal conductance (Sc.) and transpiration rate (Tr.) of upper leaves were –almost 4 times- higher than lower ones. The maximum value of Sc was achieved by T. with planting density of 28000 and by Ds. with 21000 plants fad.^-1 with means of 0.31 and 0.30 ms^-1, while, T. and Ds. with 28000 plants fad.^-1 gave the highest Tr. with mean values of 15.41 and 14.08 µg cm^-1s^-1. Direct seeds with planting density of 21000 plants fad^-1 gave the highest leaf, root and total yields (14.8, 136.0, 150.9 ton fad.^-1, respectively) in combined analysis. There were high positive correlation with the high total fresh yield and each of root length, diameter and new leaves Tr., where these correlation coefficient rates were 0.829**, 0.699* and 0.569*, respectively. Also, this investigation give chemical composition of fodder beet roots grown in sandy soil under two seasons which recorded crude protein ranged between 13.6 and 11.0% and average of crude fiber of 5.6%. The results suggest that root length and diameter as well as new leaves transpired could be important parameters for improving fodder beet productivity under sandy soil conditions at North Sinai Governorate and similar areas.