Studies on improving yield and quality of celeriac

This investigation was conducted in two successive winter seasons of 2007/2008 and 2008/2009 on celeriac plants cv. Monarch in newly reclaimed sandy soil at the experimental station of the National Research Centre at Nubaria, Beheira Governorate, Egypt, The present study included two main experiments. First experiment was carried out to study the interactive effect of mineral nitrogen and biofertilization on the growth, chemical composition and yield of celeriac plant. Biofertilization treatments composed of mixture of nitrogen fixing bacteria(Azotobacter chroococcum and Azospirillium lipoferum) either individually or combined with mineral nitrogen fertilizer at the rates of 50 ,75 and 100% of the recommended rate in addition to uninoculated control (which given the recommended dose of mineral N).A complete randomized block design with three replicates was adopted. The obtained results indicated that, in most cases, plants treated with the combination of full dose of mineral nitrogen fertilization and soil inoculation with biofertilizer recorded the highest and significant values of growth parameters, i.e plant height, leaf number and fresh and dry weight of leaves as well as chlorophyll, carotenoids, N, P, K contents in leaves tissues. The above mentioned treatment gave the highest yield of celeriac plants represented as fresh leaves (green yield) and roots and root quality, i.e., weight and length, total sugars and V.C. content. Whereas the least values of all growth parameters, yield and quality as well as nitrate content of roots were found in Plants treated only with biofertilizer. Second experiment was carried out to study the effect of foliar application with amino acids and seaweed extract on the growth, chemical composition, yield and its quality of celeriac plant. The experiment included 5 treatments resulted from spray treatments, viz. amino acids at 500 and 750 ppm and seaweed extract at 1000 and 2000 ppm in addition to check treatment (water). A complete randomized block design with three replicates was adopted. Results indicated that, spraying the plants with amino acids and seaweed extract at higher rate significantly increased plant height and fresh and dry weight of leaves compared to the control. Spraying seaweed extract at higher rate tended to have the highest values from photosyntheticpigments, P and K content of leaves whereas, amino acids at both rates significantly increased N content compared to the control as well as other treatments. Spraying plants with either amino acids or seaweed extract at higher rates significantly increased the green yield (leaves) while, seaweed extract at the two tested concentrations exhibited the highest significantly root yield compared to those of untreated check and other treatments. Spraying the plants with seaweed extract at higher rate exhibited the highest significant values of root weight, P and K contents of roots. Spraying the plants with seaweed extract and amino acids at the higher rates significantly increased total sugar content whereas, seaweed extract at two tested rates significantly increased NO3 content of roots compared to the control treatment.