EFFECTS of BIOFERTILIZATION on GROWTH, YIELD COMPONENTS and YIELD of SWEETPOTATO

Abstract

A pot experiment and tow field experiments were conducted to study the effect of Al Khaseeb organic fertilizer application rate and Azospirillum brasilense inoculation on growth and growth components of, sweetpotato (Ipomoea batatas L). Azospirillum brasilense inoculum applied with intensity of; (0, 104 and 108Cfu/ml), respectively and the three rates of Al Khaseeb Organic fertilizer applied were; (0 t/ha, 25 t/ha and 50 t/ha). The experiment was set in a factorial arrangement in a Completely Randomized Design (CRD) with three replicates. application of Al Khaseeb at the rate of 25t/ha+ AzospiriIIum 104 showed significant effect (P < 0.05) on shoot dry weight, shoot fresh weight and root length with (5.10g), (26.70 g) and (41.33cm) compared to (1.3g), (3.67g) and (16.67 cm) for uninoculated and unfertilized control. inoculation with AzospiriIIum 104 +25 t/ha of Al Khaseeb organic fertilizer showed results similar to application of 50 t/ha of Al Khaseeb organic fertilizer alone, The results indicated the great potential of using organic fertilizers and biofertilizers to improve growth of sweetpotato and 50% of Al Khaseeb organic fertilizer requirement can be saved by inoculation with AzospiriIIum 104. . Tow field experiments were conducted in the Experimental Farm of the College of Agricultural Studies, Sudan University of Sciences and Technology-Shambat and the Experimental Farm of the Faculty of Agricultural and Environmental Sciences, University of Gadarif- Tawawa, to study the effect of inoculation with Azospirillum brasilense, Flavobacterium spp, and Al Khaseeb organic fertilizer application rate on growth, yield components and yield of sweetpotato (Ipomoea batatas L). Azospirillum brasilense and Flavobacterium spp inoculum were applied at the concentration of (108Cfu/ml), with three rates of Al Khaseeb organic fertilizer; (0 t/ha, 0.8 t/ha and 1.2 t/ha). The experiments were set in a factorial arrangement in a Randomized Complete Block Design (RCBD) with three replicates. Application of (Azospirillum +1.2 t/ha of Al Khaseeb organic fertilizer) and (Azospirillum + Flavobacterium+ 0.8 t/ha of organic fertilizer) showed significant effect (P < 0.05) on sweetpotato stem length, Leaf number, branches number six and sixteen weeks after planting; with (107.67cm), (72) and(5); (193cm), (193) and(13) respectively compared to non-inoculated and non-fertilized control, also application of Azospirillum + Flavobacterium+ 0.8 t/ha of organic fertilizer showed a significant effect (P < 0.05) on marketable storage roots yield with (13.5 t/ha) compared to (6.71 t/ha) for the non-inoculated and non-fertilized control. However, the application of 1.2 t/ha of Al Khaseeb organic fertilizer alone showed lowest values in Leaf number, branches number in Shambat site. However in site 2 Tawawa(University of Gadarif) stem length at six weeks after planting and stem length, leaf number and branches number at sixteen weeks after planting, showed significant difference (P < 0.05) among treatment means; with (127.1), (270.8),(256) and (12), compared to; (88.6), (159.2), (143) and (6) for non-inoculated and non-fertilized control respectively. The results indicated the great potential of combined application of Azospirillum brasilense, Flavobacterium biofertilizers and Al Khaseeb organic fertilizer in improving growth, yield components and yield of sweetpotato under field conditions.