Effects of Biological and Chemical Sources of Fertilizers on Sunflower Yield and its Components

Abstract

Bio-fertilizers could improve nutrient availability and reduce the need to use chemical fertilizers and hold a great promise to improve crop yields. This study evaluated the individual and combined effects of bio-fertilizers and compare their efficiency with nitrogen and phosphorus chemical fertilizers on the yield of sunflower (Helianthus annuus L.) in the 2017-18 crop year in Hamedan, Iran. The experimental design includes a combination of two factorial experiments including (a) the application of the chemical nitrogen (N0=0, N1=45, N2=90 kg ha-1), and phosphorus (P0=0, P1=40, P2=80 kg ha-1) fertilizers, and (b) the application of nitrogen-fixing bacteria included Azospirillum and Azotobacter (BN0=0, BN1=0.5, BN2=1 L ha-1), and phosphate-solubilizing bacteria included Pseudomonas and Bacillus (BP0=0, BP1=0.5, BP2=1 L ha-1) bio-fertilizers that each executed in a 3 × 3 design with nine treatments and a randomized complete block designs with three replicates within the same field. Results indicated that the chemical N and P fertilizers significantly increase the grain yield, 1000-grain weight, plant dry weight, protein percentage, and harvest index. Furthermore, bio-fertilizers significantly increase the grain yield and harvest index. The result shows employing bio-fertilizers with nitrogen-fixing bacteria and phosphate-solubilizing bacteria improves the growth and yield characteristics of sunflower. Sunflower oil yield was similar among all treatments and ranged from 2.22 to 5.7 t ha-1. There was no significant interaction in grain yield between chemical and biofertilizer treatments and ranged from 5.12 to 5.88 t ha-1. A similar result between treatments with the chemical fertilizers and bio-fertilizers suggests bio-fertilizers are suitable alternatives to chemical fertilizers.