Influence of Applying Phosphate Bio-fertilizers and Different Levels of Phosphorus Sources on the Productivity, Quality and Chemical Composition of Sweet Fennel (Foeniculum Vulgare Mill.)

Attention has been focused on the use of organic natural substances and bio-fertilizers in farming due to the pollution factor and high costs of mineral fertilizers. Therefore, field trials were conducted in newly reclaimed soil during two successive winter seasons (2007/2008 and 2008/2009) at El-Nobaria region, Beheira Governorate, Egypt, to study the effect of different levels of two phosphorus sources and phosphate bio-fertilizers on vegetative growth, yield, quality and nutrients uptake by sweet fennel. Phosphate bio-fertilization included three treatments, (I) without bio-fertilizer (control); (II) VA arbuscular mycorrhizae and (III) Bacillus megaterium. Five combinations of the two P sources, .i.e. rock phosphate (20.8 % P2O5) and calcium super phosphate (15.5 % P2O5) each supplying 40 units of P2O5 /Fed. were examined. These are (a) 100% super P; (b) 75% super P + 25% rock P; (c) 50% super P + 50% rock P; (d) 25% super P + 75% rock P and (e) 100 % rock P. Results show that sweet fennel plants inoculated with VA mycorrhizae showed higher [vegetative growth parameters namely plant length, leaves number; bulb dimensions (thickness, width and length), as well as fresh and dry weight of leaves, bulbs and total plant; total green yield; physical bulb quality (flatten, cylinder and elongated shape ratios); nutritional value i.e. TSS and uptake of N, P and K] than the untreated plants. Moreover, plants un-inoculated with phosphate bio-fertilizer had higher content of total phenolic compounds. Phosphate sources and rates differed statistically in their effect on the vegetative growth of sweet fennel plants. Treatments where all phosphorus was applied as rock phosphate showed significant effect on the vegetative growth, yield and quality of bulbs and reduced total phenols, with the highest total soluble solids. Lower values of plant growth were obtained by applying 100% super P fertilizer. The results indicated that combined effect of bio-fertilization and rock phosphate treatments caused significant increases in vegetative growth, green yield, bulb quality and chemical contents. The highest vegetative growth, yield and quality as well as chemical contents were obtained by applying VA mycorrhizae combined with the rate of 100 % rock phosphate. Such treatment is environmentally safe where concentrations of both Cd and F in the obtained plants are within the permissible levels